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Re: experience using MFR5 with a 12" f5 newt ?

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  • andrew crouch
    Hi Rock, Is that a possibility? Cheers, Andrew
    Message 1 of 17 , Mar 1, 2013
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      Hi Rock,

      Is that a possibility?

      Cheers,

      Andrew

      --- In mallincam@yahoogroups.com, "Mark" <mclewis1@...> wrote:
      >
      > Andrew,
      >
      > I like the way you worded that ... "MFR-5 is designed as a 0.3x focal reducer."
      >
      > It certainly was designed for that, but it's not sold that way. As it's sold on it's own it's closer to a 0.5x reducer as Glenn has mentioned. To be capable of the reduced reduction factors you need to add the optional C thread spacers.
      >
      > If Rock (or someone else who's capable of accurately measuring it) would publish the focal length of the MFR-5 in it's various configurations (with 5 and 10mm spacers) you could use the following online calculator to determine the in focus travel requirements.
      >
      > http://www.wilmslowastro.com/software/formulae.htm (scroll down to the focal reducer section).
      >
      > Mark
      >
      > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
      > >
      > > Hi Glen and thanks,
      > >
      > > My understanding is that the MFR5 is designed as a X0.3 focal reducer, so of course it would be good to be able to squeeze as much surface brightness out of it as possible. Having said that, your points are all good ones.
      > >
      > > My secondary has some unused headroom (about the outer 10mm of its 70mm short diameter), which means I lose no light around the secondary at 0.6X FR and setting back of secondary and the FR into the light cone by the measured 40mm, so one telling point would be how much further the 0.3X configuration would push it. If you or someone could tell me the diameter of the front FR element, and the additional infocus needed to run the MFR5 as a 0.3X (compared to no FR at all), I could make a stab at calculating how far I could push it without the front element causing vignetting, and without losing too much light around the secondary. Of course, as you say, aberration is a factor so I would be interested to know if anyone else has actually tried it.
      > >
      > > Cheers,
      > >
      > > Andrew
      > >
      > >
      > >
      > > --- In mallincam@yahoogroups.com, "glennledrew" <gcledrew@> wrote:
      > > >
      > > > Andrew,
      > > > I've used my VSS and MFR-5 on a friend's 12" collapsible Skywatcher f/4.9. He had already made up a set of spacers from PVC pipe sections which snap onto the the three poles. I didn't check to see if there was aperture reduction occurring, but given the relatively small decrease in primary-to-secondary separation, if happening it must be pretty much negligible.
      > > >
      > > > I didn't install any spacers with the reducer, and so the reduction factor, as measured directly by me, was 0.5X, yielding f/2.45.
      > > >
      > > > From a variety of examinations on a few scopes, I feel there is little to be gained by adding spacers, at least when used on faster scopes such as these Newts. Already the MFR-5 is working close to the limit, whereby the front element is not far removed from itself becoming the aperture restrictor. By adding a spacer, the front lens is pushed farther up into the light cone where it's wider. If the light cone for on-axis light becomes clipped by the now too-small lens, aperture reduction is in effect.
      > > >
      > > > One can certainly continue to install spacers if the aim is to obtain a wider field, but once aperture reduction commences, the working f/ratio remains nearly constant, and so the image surface brightness increases little, if any. And of course vignetting becomes rapidly more offensive, and optical aberrations get worse.
      > > >
      > > > You would probably be hard pressed to obtain a system speed as fast as f/2, and by that point the outer field may be getting unacceptably aberrated and vignetted.
      > > >
      > > > In my own case (12" f/2.45), from a dark site and with an Orion Skyglow Imaging filter installed, the performance was quite good with 30 second integrations, even on such faint stuff as the Bubble nebula, NGC 7635.
      > > >
      > > > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
      > > > >
      > > > > I would like to hear from anyone in the group who has used an MFR5 f/3 focal reducer with a 12" or similar sized f5 newtonian to achieve around f1.7 using a 1/2" CCD video camera, and whether there are any special factors to be aware of.
      > > > >
      > > > > My newtonian is of the flextube type, so by extending the secondary cage only out to about 40mm short of its normal full extension I can obtain focus readily, at least with my current f/6 focal reducer.
      > > > >
      > > > > I am aware that by doing this there may/will be some loss of light around the edge of the secondary, so it would be good to know how far back the secondary needs to be behind its normal position to achieve focus with the MFR5.
      > > > >
      > > > > Another concern is whether there is significant distortion.
      > > > >
      > > > > Thanks,
      > > > >
      > > > > Andrew Crouch
      > > > >
      > > >
      > >
      >
    • MallinCam
      Andrew, Mark, The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the
      Message 2 of 17 , Mar 1, 2013
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        Andrew, Mark,

        The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the Meade F/3.3 older series was our model to obtain the the field of view I was looking for. Based on our optical bench at the time. The measurement were in fact F/3.3. I even got as low as F/2.9 with the MFR-5 and spacers. Problem we came up was accurate measurement on many SCT. Many SCT's do not have a dead on F /10. They varied from F/9.5 up to F/10.5. With F ratios like these on some SCT's, the actual field of view and reduction will be severely altered in the final reduction on the MFR-5 or any focal reducer for that matter.

        Mark, about specific measurements. I just came back from Celestron site, Meade, Orion and a handful others, and not one post there optical values on the focal reducer lens. Why should I? Our design is unique on the market and is applied only to video ccd sensors of 1/2" in size and is made to be used at close distance to the ccd sensor. I am not about to give any optical values to anyone. No one else does it, why should I disclose our hard work in design and trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16" Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is compatible to all SCT's RC's, ACF, Edge and more. I would not recommend using the MFR-5 on a Newtonian type optics. Main mirror would need to be moved up too much to achieve focus. The MFR-3 was design for a Newtonian in mind.

        See our website at:

        http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg

        Website page at:
        http://mallincam.tripod.com/id15.html

        Scroll down the page and find the same as above for actual images taken with a old Meade F/3.3 focal reducer and the MFR-5 comparison.


        Rock M.




        --- In mallincam@yahoogroups.com, "Mark" <mclewis1@...> wrote:
        >
        > Andrew,
        >
        > I like the way you worded that ... "MFR-5 is designed as a 0.3x focal reducer."
        >
        > It certainly was designed for that, but it's not sold that way. As it's sold on it's own it's closer to a 0.5x reducer as Glenn has mentioned. To be capable of the reduced reduction factors you need to add the optional C thread spacers.
        >
        > If Rock (or someone else who's capable of accurately measuring it) would publish the focal length of the MFR-5 in it's various configurations (with 5 and 10mm spacers) you could use the following online calculator to determine the in focus travel requirements.
        >
        > http://www.wilmslowastro.com/software/formulae.htm (scroll down to the focal reducer section).
        >
        > Mark
        >
        > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
        > >
        > > Hi Glen and thanks,
        > >
        > > My understanding is that the MFR5 is designed as a X0.3 focal reducer, so of course it would be good to be able to squeeze as much surface brightness out of it as possible. Having said that, your points are all good ones.
        > >
        > > My secondary has some unused headroom (about the outer 10mm of its 70mm short diameter), which means I lose no light around the secondary at 0.6X FR and setting back of secondary and the FR into the light cone by the measured 40mm, so one telling point would be how much further the 0.3X configuration would push it. If you or someone could tell me the diameter of the front FR element, and the additional infocus needed to run the MFR5 as a 0.3X (compared to no FR at all), I could make a stab at calculating how far I could push it without the front element causing vignetting, and without losing too much light around the secondary. Of course, as you say, aberration is a factor so I would be interested to know if anyone else has actually tried it.
        > >
        > > Cheers,
        > >
        > > Andrew
        > >
        > >
        > >
        > > --- In mallincam@yahoogroups.com, "glennledrew" <gcledrew@> wrote:
        > > >
        > > > Andrew,
        > > > I've used my VSS and MFR-5 on a friend's 12" collapsible Skywatcher f/4.9. He had already made up a set of spacers from PVC pipe sections which snap onto the the three poles. I didn't check to see if there was aperture reduction occurring, but given the relatively small decrease in primary-to-secondary separation, if happening it must be pretty much negligible.
        > > >
        > > > I didn't install any spacers with the reducer, and so the reduction factor, as measured directly by me, was 0.5X, yielding f/2.45.
        > > >
        > > > From a variety of examinations on a few scopes, I feel there is little to be gained by adding spacers, at least when used on faster scopes such as these Newts. Already the MFR-5 is working close to the limit, whereby the front element is not far removed from itself becoming the aperture restrictor. By adding a spacer, the front lens is pushed farther up into the light cone where it's wider. If the light cone for on-axis light becomes clipped by the now too-small lens, aperture reduction is in effect.
        > > >
        > > > One can certainly continue to install spacers if the aim is to obtain a wider field, but once aperture reduction commences, the working f/ratio remains nearly constant, and so the image surface brightness increases little, if any. And of course vignetting becomes rapidly more offensive, and optical aberrations get worse.
        > > >
        > > > You would probably be hard pressed to obtain a system speed as fast as f/2, and by that point the outer field may be getting unacceptably aberrated and vignetted.
        > > >
        > > > In my own case (12" f/2.45), from a dark site and with an Orion Skyglow Imaging filter installed, the performance was quite good with 30 second integrations, even on such faint stuff as the Bubble nebula, NGC 7635.
        > > >
        > > > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
        > > > >
        > > > > I would like to hear from anyone in the group who has used an MFR5 f/3 focal reducer with a 12" or similar sized f5 newtonian to achieve around f1.7 using a 1/2" CCD video camera, and whether there are any special factors to be aware of.
        > > > >
        > > > > My newtonian is of the flextube type, so by extending the secondary cage only out to about 40mm short of its normal full extension I can obtain focus readily, at least with my current f/6 focal reducer.
        > > > >
        > > > > I am aware that by doing this there may/will be some loss of light around the edge of the secondary, so it would be good to know how far back the secondary needs to be behind its normal position to achieve focus with the MFR5.
        > > > >
        > > > > Another concern is whether there is significant distortion.
        > > > >
        > > > > Thanks,
        > > > >
        > > > > Andrew Crouch
        > > > >
        > > >
        > >
        >
      • Mark
        Rock, I m sorry but I can t believe you d say that. The specifications for virtually every focal reducer on the market is either published by the manufacturer,
        Message 3 of 17 , Mar 1, 2013
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          Rock,

          I'm sorry but I can't believe you'd say that. The specifications for virtually every focal reducer on the market is either published by the manufacturer, or reseller. If a few products specs are not published it's been measured and documented by others and readily available. Not publishing any specifications on the MFR-5 is certainly your choice but suggesting that it's normal and others don't do it simply isn't true.

          A couple of minutes on the web provides the following ...

          Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm focal length, 41mm clear aperture, 4 element, spacing 105-110mm (difference are because of different manufacturer).

          Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
          Antares .5x 1.25" - 95mm fl, 47.5mm spacing
          Antares .7x 2" - 220mm fl, 66mm spacing
          GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
          William Optics IV - 66-68mm spacing
          Orion .8x imaging - 55mm spacing (they call this "backfocus")

          Optec not only published the focal length and spacing requirements for their 3 focal reducers they include the measurements for a whole variety of camera and adapters. The also publish a ton more optical information (spot, encircled energy, ray trace, and field curvature diagrams) about their focal reducers.

          Worried about your optical design? I don't understand how publishing focal length and spacing measurements is going to give away any of your trade secrets. It will however make it easier for folks to use your products with a variety of adapters and spacers and be able to estimate it's performance without resorting to measuring actual images.

          The minor variations in the actual focal length of commercial moving mirror SCTs is not going to account for a difference of .33x to .5x seen in the MFR-5 used without spacers. Certainly used with other telescope designs there will be some small differences in the focal reduction factors seen. From experience with a variety of other focual reducers I would expect fl variations of maybe 10% or so (between f4 Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly not .33x to .5x when used in the same manner (no spacers).

          Given these discussed discrepancies (Glenn's measured .5x on Newtonians and refractors and your original .33x measurement on an f10 Meade SCT) it would be very helpful if you cleared the air and offered a plausible explanation.


          Mark


          --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@...> wrote:
          >
          > Andrew, Mark,
          >
          > The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the Meade F/3.3 older series was our model to obtain the the field of view I was looking for. Based on our optical bench at the time. The measurement were in fact F/3.3. I even got as low as F/2.9 with the MFR-5 and spacers. Problem we came up was accurate measurement on many SCT. Many SCT's do not have a dead on F /10. They varied from F/9.5 up to F/10.5. With F ratios like these on some SCT's, the actual field of view and reduction will be severely altered in the final reduction on the MFR-5 or any focal reducer for that matter.
          >
          > Mark, about specific measurements. I just came back from Celestron site, Meade, Orion and a handful others, and not one post there optical values on the focal reducer lens. Why should I? Our design is unique on the market and is applied only to video ccd sensors of 1/2" in size and is made to be used at close distance to the ccd sensor. I am not about to give any optical values to anyone. No one else does it, why should I disclose our hard work in design and trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16" Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is compatible to all SCT's RC's, ACF, Edge and more. I would not recommend using the MFR-5 on a Newtonian type optics. Main mirror would need to be moved up too much to achieve focus. The MFR-3 was design for a Newtonian in mind.
          >
          > See our website at:
          >
          > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
          >
          > Website page at:
          > http://mallincam.tripod.com/id15.html
          >
          > Scroll down the page and find the same as above for actual images taken with a old Meade F/3.3 focal reducer and the MFR-5 comparison.
          >
          >
          > Rock M.
          >
          >
          >
        • MallinCam
          Mark, I think you misunderstood me. Here s a sample from Meade website: http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html All Meade mention
          Message 4 of 17 , Mar 1, 2013
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            Mark,

            I think you misunderstood me.

            Here's a sample from Meade website:

            http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html

            All Meade mention is element size which is 41 mm in diameter.
            MFR-5 is 4 elements variable with spacers, element are 25 mm and 22 mm for a total of 4 elements. Is that what you wanted to hear?.

            Meade for example specify a specific distance which can vary with such a large amount that their F/6.2 can actually go down from F 5 to about F/7 when used on a SCT. They do specify a SCT usage. I also offered me reference on a SCT, not another scope. It is written on the MallinCam website. I have given you in my previous message on this group about the variety of F ratio being not consistent with several SCT out there.

            Mark, please, I am not here to start the same type of arguments as on CN but I must admit your reply has the same tone where words are everything it would seem. My apology for my french education. English is not my best to describe what you need to hear.

            On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.

            Rock Mallin





            --- In mallincam@yahoogroups.com, "Mark" <mclewis1@...> wrote:
            >
            > Rock,
            >
            > I'm sorry but I can't believe you'd say that. The specifications for virtually every focal reducer on the market is either published by the manufacturer, or reseller. If a few products specs are not published it's been measured and documented by others and readily available. Not publishing any specifications on the MFR-5 is certainly your choice but suggesting that it's normal and others don't do it simply isn't true.
            >
            > A couple of minutes on the web provides the following ...
            >
            > Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm focal length, 41mm clear aperture, 4 element, spacing 105-110mm (difference are because of different manufacturer).
            >
            > Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
            > Antares .5x 1.25" - 95mm fl, 47.5mm spacing
            > Antares .7x 2" - 220mm fl, 66mm spacing
            > GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
            > William Optics IV - 66-68mm spacing
            > Orion .8x imaging - 55mm spacing (they call this "backfocus")
            >
            > Optec not only published the focal length and spacing requirements for their 3 focal reducers they include the measurements for a whole variety of camera and adapters. The also publish a ton more optical information (spot, encircled energy, ray trace, and field curvature diagrams) about their focal reducers.
            >
            > Worried about your optical design? I don't understand how publishing focal length and spacing measurements is going to give away any of your trade secrets. It will however make it easier for folks to use your products with a variety of adapters and spacers and be able to estimate it's performance without resorting to measuring actual images.
            >
            > The minor variations in the actual focal length of commercial moving mirror SCTs is not going to account for a difference of .33x to .5x seen in the MFR-5 used without spacers. Certainly used with other telescope designs there will be some small differences in the focal reduction factors seen. From experience with a variety of other focual reducers I would expect fl variations of maybe 10% or so (between f4 Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly not .33x to .5x when used in the same manner (no spacers).
            >
            > Given these discussed discrepancies (Glenn's measured .5x on Newtonians and refractors and your original .33x measurement on an f10 Meade SCT) it would be very helpful if you cleared the air and offered a plausible explanation.
            >
            >
            > Mark
            >
            >
            > --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@> wrote:
            > >
            > > Andrew, Mark,
            > >
            > > The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the Meade F/3.3 older series was our model to obtain the the field of view I was looking for. Based on our optical bench at the time. The measurement were in fact F/3.3. I even got as low as F/2.9 with the MFR-5 and spacers. Problem we came up was accurate measurement on many SCT. Many SCT's do not have a dead on F /10. They varied from F/9.5 up to F/10.5. With F ratios like these on some SCT's, the actual field of view and reduction will be severely altered in the final reduction on the MFR-5 or any focal reducer for that matter.
            > >
            > > Mark, about specific measurements. I just came back from Celestron site, Meade, Orion and a handful others, and not one post there optical values on the focal reducer lens. Why should I? Our design is unique on the market and is applied only to video ccd sensors of 1/2" in size and is made to be used at close distance to the ccd sensor. I am not about to give any optical values to anyone. No one else does it, why should I disclose our hard work in design and trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16" Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is compatible to all SCT's RC's, ACF, Edge and more. I would not recommend using the MFR-5 on a Newtonian type optics. Main mirror would need to be moved up too much to achieve focus. The MFR-3 was design for a Newtonian in mind.
            > >
            > > See our website at:
            > >
            > > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
            > >
            > > Website page at:
            > > http://mallincam.tripod.com/id15.html
            > >
            > > Scroll down the page and find the same as above for actual images taken with a old Meade F/3.3 focal reducer and the MFR-5 comparison.
            > >
            > >
            > > Rock M.
            > >
            > >
            > >
            >
          • Murray
            Rock , politics should be left to politicians, they know how to manouvre around the BS, thats what they do best, you should do what you do best, creating
            Message 5 of 17 , Mar 1, 2013
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              Rock , politics should be left to politicians, they know how to manouvre around the BS, thats what they do best, you should do what you do best, creating enjoyment for all of us who appreciate you, your friend Murray, see you in July

              --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@...> wrote:
              >
              > Mark,
              >
              > I think you misunderstood me.
              >
              > Here's a sample from Meade website:
              >
              > http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html
              >
              > All Meade mention is element size which is 41 mm in diameter.
              > MFR-5 is 4 elements variable with spacers, element are 25 mm and 22 mm for a total of 4 elements. Is that what you wanted to hear?.
              >
              > Meade for example specify a specific distance which can vary with such a large amount that their F/6.2 can actually go down from F 5 to about F/7 when used on a SCT. They do specify a SCT usage. I also offered me reference on a SCT, not another scope. It is written on the MallinCam website. I have given you in my previous message on this group about the variety of F ratio being not consistent with several SCT out there.
              >
              > Mark, please, I am not here to start the same type of arguments as on CN but I must admit your reply has the same tone where words are everything it would seem. My apology for my french education. English is not my best to describe what you need to hear.
              >
              > On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.
              >
              > Rock Mallin
              >
              >
              >
              >
              >
              > --- In mallincam@yahoogroups.com, "Mark" <mclewis1@> wrote:
              > >
              > > Rock,
              > >
              > > I'm sorry but I can't believe you'd say that. The specifications for virtually every focal reducer on the market is either published by the manufacturer, or reseller. If a few products specs are not published it's been measured and documented by others and readily available. Not publishing any specifications on the MFR-5 is certainly your choice but suggesting that it's normal and others don't do it simply isn't true.
              > >
              > > A couple of minutes on the web provides the following ...
              > >
              > > Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm focal length, 41mm clear aperture, 4 element, spacing 105-110mm (difference are because of different manufacturer).
              > >
              > > Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
              > > Antares .5x 1.25" - 95mm fl, 47.5mm spacing
              > > Antares .7x 2" - 220mm fl, 66mm spacing
              > > GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
              > > William Optics IV - 66-68mm spacing
              > > Orion .8x imaging - 55mm spacing (they call this "backfocus")
              > >
              > > Optec not only published the focal length and spacing requirements for their 3 focal reducers they include the measurements for a whole variety of camera and adapters. The also publish a ton more optical information (spot, encircled energy, ray trace, and field curvature diagrams) about their focal reducers.
              > >
              > > Worried about your optical design? I don't understand how publishing focal length and spacing measurements is going to give away any of your trade secrets. It will however make it easier for folks to use your products with a variety of adapters and spacers and be able to estimate it's performance without resorting to measuring actual images.
              > >
              > > The minor variations in the actual focal length of commercial moving mirror SCTs is not going to account for a difference of .33x to .5x seen in the MFR-5 used without spacers. Certainly used with other telescope designs there will be some small differences in the focal reduction factors seen. From experience with a variety of other focual reducers I would expect fl variations of maybe 10% or so (between f4 Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly not .33x to .5x when used in the same manner (no spacers).
              > >
              > > Given these discussed discrepancies (Glenn's measured .5x on Newtonians and refractors and your original .33x measurement on an f10 Meade SCT) it would be very helpful if you cleared the air and offered a plausible explanation.
              > >
              > >
              > > Mark
              > >
              > >
              > > --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@> wrote:
              > > >
              > > > Andrew, Mark,
              > > >
              > > > The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the Meade F/3.3 older series was our model to obtain the the field of view I was looking for. Based on our optical bench at the time. The measurement were in fact F/3.3. I even got as low as F/2.9 with the MFR-5 and spacers. Problem we came up was accurate measurement on many SCT. Many SCT's do not have a dead on F /10. They varied from F/9.5 up to F/10.5. With F ratios like these on some SCT's, the actual field of view and reduction will be severely altered in the final reduction on the MFR-5 or any focal reducer for that matter.
              > > >
              > > > Mark, about specific measurements. I just came back from Celestron site, Meade, Orion and a handful others, and not one post there optical values on the focal reducer lens. Why should I? Our design is unique on the market and is applied only to video ccd sensors of 1/2" in size and is made to be used at close distance to the ccd sensor. I am not about to give any optical values to anyone. No one else does it, why should I disclose our hard work in design and trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16" Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is compatible to all SCT's RC's, ACF, Edge and more. I would not recommend using the MFR-5 on a Newtonian type optics. Main mirror would need to be moved up too much to achieve focus. The MFR-3 was design for a Newtonian in mind.
              > > >
              > > > See our website at:
              > > >
              > > > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
              > > >
              > > > Website page at:
              > > > http://mallincam.tripod.com/id15.html
              > > >
              > > > Scroll down the page and find the same as above for actual images taken with a old Meade F/3.3 focal reducer and the MFR-5 comparison.
              > > >
              > > >
              > > > Rock M.
              > > >
              > > >
              > > >
              > >
              >
            • DON MOSES
              The world is full of people who think they know what Rock should do. If they did, they would be selling their own brand of custom, hand made camera instead of
              Message 6 of 17 , Mar 1, 2013
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                The world is full of people who think they know what Rock should do. If
                they did, they would be selling their own brand of custom, hand made
                camera instead of complaining about what Rock should or should not do.
                Rock gave an explanation for why he doesn't post the requested data.
                That should have been enough. That is exactly the reason why, when I
                asked about HDMI outputs, I didn't press the issue.

                Come to think of it, this is pretty much true for everything from how to
                wash a car to what religious beliefs one should or should not hold. Some
                people are just natural born whiners. As for me, I only whine when it is
                really, really important, and when I'm absolutely positively right.

                Don M.


                On 3/1/13 11:57 AM, Murray wrote:
                >
                > Rock , politics should be left to politicians, they know how to
                > manouvre around the BS, thats what they do best, you should do what
                > you do best, creating enjoyment for all of us who appreciate you, your
                > friend Murray, see you in July
                >
                > --- In mallincam@yahoogroups.com <mailto:mallincam%40yahoogroups.com>,
                > "MallinCam" wrote:
                > >
                > > Mark,
                > >
                > > I think you misunderstood me.
                > >
                > > Here's a sample from Meade website:
                > >
                > > http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html
                > >
                > > All Meade mention is element size which is 41 mm in diameter.
                > > MFR-5 is 4 elements variable with spacers, element are 25 mm and 22
                > mm for a total of 4 elements. Is that what you wanted to hear?.
                > >
                > > Meade for example specify a specific distance which can vary with
                > such a large amount that their F/6.2 can actually go down from F 5 to
                > about F/7 when used on a SCT. They do specify a SCT usage. I also
                > offered me reference on a SCT, not another scope. It is written on the
                > MallinCam website. I have given you in my previous message on this
                > group about the variety of F ratio being not consistent with several
                > SCT out there.
                > >
                > > Mark, please, I am not here to start the same type of arguments as
                > on CN but I must admit your reply has the same tone where words are
                > everything it would seem. My apology for my french education. English
                > is not my best to describe what you need to hear.
                > >
                > > On second thoughts, improper tones and argumentation are done with
                > me. Seem some wanted to crucify me upside down all the time. I'm off
                > this list too for while, I need a break from this BS. Have fun. I have
                > better things to do such as continue to work on cameras and new
                > upcoming products that benefit astronomers. Attacking someone and
                > belittle people seem to be a fun thing on the internet. Hope my reply
                > does not upset you too much, Mark. I always had respect for you and
                > always will.
                > >
                > > Rock Mallin
                > >
                > >
                > >
                > >
                > >
                > > --- In mallincam@yahoogroups.com
                > <mailto:mallincam%40yahoogroups.com>, "Mark" wrote:
                > > >
                > > > Rock,
                > > >
                > > > I'm sorry but I can't believe you'd say that. The specifications
                > for virtually every focal reducer on the market is either published by
                > the manufacturer, or reseller. If a few products specs are not
                > published it's been measured and documented by others and readily
                > available. Not publishing any specifications on the MFR-5 is certainly
                > your choice but suggesting that it's normal and others don't do it
                > simply isn't true.
                > > >
                > > > A couple of minutes on the web provides the following ...
                > > >
                > > > Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm
                > focal length, 41mm clear aperture, 4 element, spacing 105-110mm
                > (difference are because of different manufacturer).
                > > >
                > > > Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
                > > > Antares .5x 1.25" - 95mm fl, 47.5mm spacing
                > > > Antares .7x 2" - 220mm fl, 66mm spacing
                > > > GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
                > > > William Optics IV - 66-68mm spacing
                > > > Orion .8x imaging - 55mm spacing (they call this "backfocus")
                > > >
                > > > Optec not only published the focal length and spacing requirements
                > for their 3 focal reducers they include the measurements for a whole
                > variety of camera and adapters. The also publish a ton more optical
                > information (spot, encircled energy, ray trace, and field curvature
                > diagrams) about their focal reducers.
                > > >
                > > > Worried about your optical design? I don't understand how
                > publishing focal length and spacing measurements is going to give away
                > any of your trade secrets. It will however make it easier for folks to
                > use your products with a variety of adapters and spacers and be able
                > to estimate it's performance without resorting to measuring actual images.
                > > >
                > > > The minor variations in the actual focal length of commercial
                > moving mirror SCTs is not going to account for a difference of .33x to
                > .5x seen in the MFR-5 used without spacers. Certainly used with other
                > telescope designs there will be some small differences in the focal
                > reduction factors seen. From experience with a variety of other focual
                > reducers I would expect fl variations of maybe 10% or so (between f4
                > Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly
                > not .33x to .5x when used in the same manner (no spacers).
                > > >
                > > > Given these discussed discrepancies (Glenn's measured .5x on
                > Newtonians and refractors and your original .33x measurement on an f10
                > Meade SCT) it would be very helpful if you cleared the air and offered
                > a plausible explanation.
                > > >
                > > >
                > > > Mark
                > > >
                > > >
                > > > --- In mallincam@yahoogroups.com
                > <mailto:mallincam%40yahoogroups.com>, "MallinCam" wrote:
                > > > >
                > > > > Andrew, Mark,
                > > > >
                > > > > The website site does show a comparable image using a 1996 Meade
                > F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by
                > hands, the Meade F/3.3 older series was our model to obtain the the
                > field of view I was looking for. Based on our optical bench at the
                > time. The measurement were in fact F/3.3. I even got as low as F/2.9
                > with the MFR-5 and spacers. Problem we came up was accurate
                > measurement on many SCT. Many SCT's do not have a dead on F /10. They
                > varied from F/9.5 up to F/10.5. With F ratios like these on some
                > SCT's, the actual field of view and reduction will be severely altered
                > in the final reduction on the MFR-5 or any focal reducer for that matter.
                > > > >
                > > > > Mark, about specific measurements. I just came back from
                > Celestron site, Meade, Orion and a handful others, and not one post
                > there optical values on the focal reducer lens. Why should I? Our
                > design is unique on the market and is applied only to video ccd
                > sensors of 1/2" in size and is made to be used at close distance to
                > the ccd sensor. I am not about to give any optical values to anyone.
                > No one else does it, why should I disclose our hard work in design and
                > trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16"
                > Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is
                > compatible to all SCT's RC's, ACF, Edge and more. I would not
                > recommend using the MFR-5 on a Newtonian type optics. Main mirror
                > would need to be moved up too much to achieve focus. The MFR-3 was
                > design for a Newtonian in mind.
                > > > >
                > > > > See our website at:
                > > > >
                > > > >
                > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
                > > > >
                > > > > Website page at:
                > > > > http://mallincam.tripod.com/id15.html
                > > > >
                > > > > Scroll down the page and find the same as above for actual
                > images taken with a old Meade F/3.3 focal reducer and the MFR-5
                > comparison.
                > > > >
                > > > >
                > > > > Rock M.
                > > > >
                > > > >
                > > > >
                > > >
                > >
                >
                >
              • Gary Shannon
                Must be pick on Rock month, er wait, months, this is March, must be pick on Rock year. Hang in there buddy, most of us,{hundreds} are behind you 100%....Gar
                Message 7 of 17 , Mar 1, 2013
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                  Must be pick on Rock month, er wait, months, this is March, must be pick on Rock year.
                  Hang in there buddy, most of us,{hundreds} are behind you 100%....Gar
                  Gary Shannon
                  Mt. Chestnut Obs.




                  ________________________________
                  From: DON MOSES <RCFLYER@...>
                  To: mallincam@yahoogroups.com
                  Sent: Friday, March 1, 2013 2:42 PM
                  Subject: Re: [MallinCam] Re: experience using MFR5 with a 12" f5 newt ?

                  The world is full of people who think they know what Rock should do. If
                  they did, they would be selling their own brand of custom, hand made
                  camera instead of complaining about what Rock should or should not do.
                  Rock gave an explanation for why he doesn't post the requested data.
                  That should have been enough. That is exactly the reason why, when I
                  asked about HDMI outputs, I didn't press the issue.

                  Come to think of it, this is pretty much true for everything from how to
                  wash a car to what religious beliefs one should or should not hold. Some
                  people are just natural born whiners. As for me, I only whine when it is
                  really, really important, and when I'm absolutely positively right.

                  Don M.


                  On 3/1/13 11:57 AM, Murray wrote:
                  >
                  > Rock , politics should be left to politicians, they know how to
                  > manouvre around the BS, thats what they do best, you should do what
                  > you do best, creating enjoyment for all of us who appreciate you, your
                  > friend Murray, see you in July
                  >
                  > --- In mallincam@yahoogroups.com <mailto:mallincam%40yahoogroups.com>,
                  > "MallinCam" wrote:
                  > >
                  > > Mark,
                  > >
                  > > I think you misunderstood me.
                  > >
                  > > Here's a sample from Meade website:
                  > >
                  > > http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html
                  > >
                  > > All Meade mention is element size which is 41 mm in diameter.
                  > > MFR-5 is 4 elements variable with spacers, element are 25 mm and 22
                  > mm for a total of 4 elements. Is that what you wanted to hear?.
                  > >
                  > > Meade for example specify a specific distance which can vary with
                  > such a large amount that their F/6.2 can actually go down from F 5 to
                  > about F/7 when used on a SCT. They do specify a SCT usage. I also
                  > offered me reference on a SCT, not another scope. It is written on the
                  > MallinCam website. I have given you in my previous message on this
                  > group about the variety of F ratio being not consistent with several
                  > SCT out there.
                  > >
                  > > Mark, please, I am not here to start the same type of arguments as
                  > on CN but I must admit your reply has the same tone where words are
                  > everything it would seem. My apology for my french education. English
                  > is not my best to describe what you need to hear.
                  > >
                  > > On second thoughts, improper tones and argumentation are done with
                  > me. Seem some wanted to crucify me upside down all the time. I'm off
                  > this list too for while, I need a break from this BS. Have fun. I have
                  > better things to do such as continue to work on cameras and new
                  > upcoming products that benefit astronomers. Attacking someone and
                  > belittle people seem to be a fun thing on the internet. Hope my reply
                  > does not upset you too much, Mark. I always had respect for you and
                  > always will.
                  > >
                  > > Rock Mallin
                  > >
                  > >
                  > >
                  > >
                  > >
                  > > --- In mallincam@yahoogroups.com
                  > <mailto:mallincam%40yahoogroups.com>, "Mark" wrote:
                  > > >
                  > > > Rock,
                  > > >
                  > > > I'm sorry but I can't believe you'd say that. The specifications
                  > for virtually every focal reducer on the market is either published by
                  > the manufacturer, or reseller. If a few products specs are not
                  > published it's been measured and documented by others and readily
                  > available. Not publishing any specifications on the MFR-5 is certainly
                  > your choice but suggesting that it's normal and others don't do it
                  > simply isn't true.
                  > > >
                  > > > A couple of minutes on the web provides the following ...
                  > > >
                  > > > Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm
                  > focal length, 41mm clear aperture, 4 element, spacing 105-110mm
                  > (difference are because of different manufacturer).
                  > > >
                  > > > Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
                  > > > Antares .5x 1.25" - 95mm fl, 47.5mm spacing
                  > > > Antares .7x 2" - 220mm fl, 66mm spacing
                  > > > GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
                  > > > William Optics IV - 66-68mm spacing
                  > > > Orion .8x imaging - 55mm spacing (they call this "backfocus")
                  > > >
                  > > > Optec not only published the focal length and spacing requirements
                  > for their 3 focal reducers they include the measurements for a whole
                  > variety of camera and adapters. The also publish a ton more optical
                  > information (spot, encircled energy, ray trace, and field curvature
                  > diagrams) about their focal reducers.
                  > > >
                  > > > Worried about your optical design? I don't understand how
                  > publishing focal length and spacing measurements is going to give away
                  > any of your trade secrets. It will however make it easier for folks to
                  > use your products with a variety of adapters and spacers and be able
                  > to estimate it's performance without resorting to measuring actual images.
                  > > >
                  > > > The minor variations in the actual focal length of commercial
                  > moving mirror SCTs is not going to account for a difference of .33x to
                  > .5x seen in the MFR-5 used without spacers. Certainly used with other
                  > telescope designs there will be some small differences in the focal
                  > reduction factors seen. From experience with a variety of other focual
                  > reducers I would expect fl variations of maybe 10% or so (between f4
                  > Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly
                  > not .33x to .5x when used in the same manner (no spacers).
                  > > >
                  > > > Given these discussed discrepancies (Glenn's measured .5x on
                  > Newtonians and refractors and your original .33x measurement on an f10
                  > Meade SCT) it would be very helpful if you cleared the air and offered
                  > a plausible explanation.
                  > > >
                  > > >
                  > > > Mark
                  > > >
                  > > >
                  > > > --- In mallincam@yahoogroups.com
                  > <mailto:mallincam%40yahoogroups.com>, "MallinCam" wrote:
                  > > > >
                  > > > > Andrew, Mark,
                  > > > >
                  > > > > The website site does show a comparable image using a 1996 Meade
                  > F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by
                  > hands, the Meade F/3.3 older series was our model to obtain the the
                  > field of view I was looking for. Based on our optical bench at the
                  > time. The measurement were in fact F/3.3. I even got as low as F/2.9
                  > with the MFR-5 and spacers. Problem we came up was accurate
                  > measurement on many SCT. Many SCT's do not have a dead on F /10. They
                  > varied from F/9.5 up to F/10.5. With F ratios like these on some
                  > SCT's, the actual field of view and reduction will be severely altered
                  > in the final reduction on the MFR-5 or any focal reducer for that matter.
                  > > > >
                  > > > > Mark, about specific measurements. I just came back from
                  > Celestron site, Meade, Orion and a handful others, and not one post
                  > there optical values on the focal reducer lens. Why should I? Our
                  > design is unique on the market and is applied only to video ccd
                  > sensors of 1/2" in size and is made to be used at close distance to
                  > the ccd sensor. I am not about to give any optical values to anyone.
                  > No one else does it, why should I disclose our hard work in design and
                  > trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16"
                  > Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is
                  > compatible to all SCT's RC's, ACF, Edge and more. I would not
                  > recommend using the MFR-5 on a Newtonian type optics. Main mirror
                  > would need to be moved up too much to achieve focus. The MFR-3 was
                  > design for a Newtonian in mind.
                  > > > >
                  > > > > See our website at:
                  > > > >
                  > > > >
                  > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
                  > > > >
                  > > > > Website page at:
                  > > > > http://mallincam.tripod.com/id15.html
                  > > > >
                  > > > > Scroll down the page and find the same as above for actual
                  > images taken with a old Meade F/3.3 focal reducer and the MFR-5
                  > comparison.
                  > > > >
                  > > > >
                  > > > > Rock M.
                  > > > >
                  > > > >
                  > > > >
                  > > >
                  > >
                  >
                  >



                  ------------------------------------

                  Yahoo! Groups Links



                  [Non-text portions of this message have been removed]
                • Glenn MacDonald
                  Well said Don! and I agree. What s that saying... Some people make things happen, some watch things happen, while others wonder what has happened” Now they
                  Message 8 of 17 , Mar 1, 2013
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                    Well said Don! and I agree.

                    What's that saying..."Some people make things happen, some watch things
                    happen, while others wonder what has happened� Now they see what Rock has
                    created and accomplished and they become jealous and trying to stop him
                    anyway they can...but never will. It's simply they just don't have the
                    genius in them... but Rock sure does!
                    Rock On! keep them wondering what just happened LOL.
                    Regards,
                    Glenn MacDonald

                    On Fri, Mar 1, 2013 at 2:42 PM, DON MOSES <RCFLYER@...> wrote:

                    > The world is full of people who think they know what Rock should do. If
                    > they did, they would be selling their own brand of custom, hand made
                    > camera instead of complaining about what Rock should or should not do.
                    > Rock gave an explanation for why he doesn't post the requested data.
                    > That should have been enough. That is exactly the reason why, when I
                    > asked about HDMI outputs, I didn't press the issue.
                    >
                    > Come to think of it, this is pretty much true for everything from how to
                    > wash a car to what religious beliefs one should or should not hold. Some
                    > people are just natural born whiners. As for me, I only whine when it is
                    > really, really important, and when I'm absolutely positively right.
                    >
                    > Don M.
                    >
                    >
                    > On 3/1/13 11:57 AM, Murray wrote:
                    > >
                    > > Rock , politics should be left to politicians, they know how to
                    > > manouvre around the BS, thats what they do best, you should do what
                    > > you do best, creating enjoyment for all of us who appreciate you, your
                    > > friend Murray, see you in July
                    > >
                    > > --- In mallincam@yahoogroups.com <mailto:mallincam%40yahoogroups.com>,
                    > > "MallinCam" wrote:
                    > > >
                    > > > Mark,
                    > > >
                    > > > I think you misunderstood me.
                    > > >
                    > > > Here's a sample from Meade website:
                    > > >
                    > > > http://store.meade.com/meade-f-6-3-focal-reducer-field-flattener.html
                    > > >
                    > > > All Meade mention is element size which is 41 mm in diameter.
                    > > > MFR-5 is 4 elements variable with spacers, element are 25 mm and 22
                    > > mm for a total of 4 elements. Is that what you wanted to hear?.
                    > > >
                    > > > Meade for example specify a specific distance which can vary with
                    > > such a large amount that their F/6.2 can actually go down from F 5 to
                    > > about F/7 when used on a SCT. They do specify a SCT usage. I also
                    > > offered me reference on a SCT, not another scope. It is written on the
                    > > MallinCam website. I have given you in my previous message on this
                    > > group about the variety of F ratio being not consistent with several
                    > > SCT out there.
                    > > >
                    > > > Mark, please, I am not here to start the same type of arguments as
                    > > on CN but I must admit your reply has the same tone where words are
                    > > everything it would seem. My apology for my french education. English
                    > > is not my best to describe what you need to hear.
                    > > >
                    > > > On second thoughts, improper tones and argumentation are done with
                    > > me. Seem some wanted to crucify me upside down all the time. I'm off
                    > > this list too for while, I need a break from this BS. Have fun. I have
                    > > better things to do such as continue to work on cameras and new
                    > > upcoming products that benefit astronomers. Attacking someone and
                    > > belittle people seem to be a fun thing on the internet. Hope my reply
                    > > does not upset you too much, Mark. I always had respect for you and
                    > > always will.
                    > > >
                    > > > Rock Mallin
                    > > >
                    > > >
                    > > >
                    > > >
                    > > >
                    > > > --- In mallincam@yahoogroups.com
                    > > <mailto:mallincam%40yahoogroups.com>, "Mark" wrote:
                    > > > >
                    > > > > Rock,
                    > > > >
                    > > > > I'm sorry but I can't believe you'd say that. The specifications
                    > > for virtually every focal reducer on the market is either published by
                    > > the manufacturer, or reseller. If a few products specs are not
                    > > published it's been measured and documented by others and readily
                    > > available. Not publishing any specifications on the MFR-5 is certainly
                    > > your choice but suggesting that it's normal and others don't do it
                    > > simply isn't true.
                    > > > >
                    > > > > A couple of minutes on the web provides the following ...
                    > > > >
                    > > > > Celestron/Meade/Antares f6.3 focal reducer corrector - 220-285mm
                    > > focal length, 41mm clear aperture, 4 element, spacing 105-110mm
                    > > (difference are because of different manufacturer).
                    > > > >
                    > > > > Meade f3.3 SCT focal reducer - 85mm fl, 57mm spacing,
                    > > > > Antares .5x 1.25" - 95mm fl, 47.5mm spacing
                    > > > > Antares .7x 2" - 220mm fl, 66mm spacing
                    > > > > GSO .5x 1.25" - 101mm* fl, 51mm* spacing (* estimate by reseller)
                    > > > > William Optics IV - 66-68mm spacing
                    > > > > Orion .8x imaging - 55mm spacing (they call this "backfocus")
                    > > > >
                    > > > > Optec not only published the focal length and spacing requirements
                    > > for their 3 focal reducers they include the measurements for a whole
                    > > variety of camera and adapters. The also publish a ton more optical
                    > > information (spot, encircled energy, ray trace, and field curvature
                    > > diagrams) about their focal reducers.
                    > > > >
                    > > > > Worried about your optical design? I don't understand how
                    > > publishing focal length and spacing measurements is going to give away
                    > > any of your trade secrets. It will however make it easier for folks to
                    > > use your products with a variety of adapters and spacers and be able
                    > > to estimate it's performance without resorting to measuring actual
                    > images.
                    > > > >
                    > > > > The minor variations in the actual focal length of commercial
                    > > moving mirror SCTs is not going to account for a difference of .33x to
                    > > .5x seen in the MFR-5 used without spacers. Certainly used with other
                    > > telescope designs there will be some small differences in the focal
                    > > reduction factors seen. From experience with a variety of other focual
                    > > reducers I would expect fl variations of maybe 10% or so (between f4
                    > > Newtonians, f5-7 refractors, f8 RCs, f10-11 SCTs) ... but certainly
                    > > not .33x to .5x when used in the same manner (no spacers).
                    > > > >
                    > > > > Given these discussed discrepancies (Glenn's measured .5x on
                    > > Newtonians and refractors and your original .33x measurement on an f10
                    > > Meade SCT) it would be very helpful if you cleared the air and offered
                    > > a plausible explanation.
                    > > > >
                    > > > >
                    > > > > Mark
                    > > > >
                    > > > >
                    > > > > --- In mallincam@yahoogroups.com
                    > > <mailto:mallincam%40yahoogroups.com>, "MallinCam" wrote:
                    > > > > >
                    > > > > > Andrew, Mark,
                    > > > > >
                    > > > > > The website site does show a comparable image using a 1996 Meade
                    > > F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by
                    > > hands, the Meade F/3.3 older series was our model to obtain the the
                    > > field of view I was looking for. Based on our optical bench at the
                    > > time. The measurement were in fact F/3.3. I even got as low as F/2.9
                    > > with the MFR-5 and spacers. Problem we came up was accurate
                    > > measurement on many SCT. Many SCT's do not have a dead on F /10. They
                    > > varied from F/9.5 up to F/10.5. With F ratios like these on some
                    > > SCT's, the actual field of view and reduction will be severely altered
                    > > in the final reduction on the MFR-5 or any focal reducer for that matter.
                    > > > > >
                    > > > > > Mark, about specific measurements. I just came back from
                    > > Celestron site, Meade, Orion and a handful others, and not one post
                    > > there optical values on the focal reducer lens. Why should I? Our
                    > > design is unique on the market and is applied only to video ccd
                    > > sensors of 1/2" in size and is made to be used at close distance to
                    > > the ccd sensor. I am not about to give any optical values to anyone.
                    > > No one else does it, why should I disclose our hard work in design and
                    > > trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16"
                    > > Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is
                    > > compatible to all SCT's RC's, ACF, Edge and more. I would not
                    > > recommend using the MFR-5 on a Newtonian type optics. Main mirror
                    > > would need to be moved up too much to achieve focus. The MFR-3 was
                    > > design for a Newtonian in mind.
                    > > > > >
                    > > > > > See our website at:
                    > > > > >
                    > > > > >
                    > >
                    > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
                    > > > > >
                    > > > > > Website page at:
                    > > > > > http://mallincam.tripod.com/id15.html
                    > > > > >
                    > > > > > Scroll down the page and find the same as above for actual
                    > > images taken with a old Meade F/3.3 focal reducer and the MFR-5
                    > > comparison.
                    > > > > >
                    > > > > >
                    > > > > > Rock M.
                    > > > > >
                    > > > > >
                    > > > > >
                    > > > >
                    > > >
                    > >
                    > >
                    >
                    >
                    >
                    > ------------------------------------
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >


                    [Non-text portions of this message have been removed]
                  • topjimmy2010
                    I don t think Mark s tone was all that bad actually. I don t think he was whining. It is important though that everyone understand Rock s position. He s had
                    Message 9 of 17 , Mar 1, 2013
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                      I don't think Mark's tone was all that bad actually. I don't think he was whining. It is important though that everyone understand Rock's position. He's had to deal with a lot of crap over the last year, alot of which noone on this group has a clue about. A person can't be held in that situation for very long before they start to get frustrated and defensive, even someone as genuinely nice as Rock. I have seen enough personnally to put my trust in Rock, and I respect any position he takes on the sharing of his hard earned technical knowledge.

                      Now everybody take a deeeeep breath...and exhale...good.

                      Regards,

                      Jim Thompson
                      AbbeyRoadObservatory

                      --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@...> wrote:
                      >
                      > Mark,
                      >
                      > I think you misunderstood me.
                      >
                      > .........snip
                      >
                      >
                      > On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.
                      >
                      > Rock Mallin
                      >
                    • Murray
                      all this over a man and a camera? i dont understand whats happening!this is supposed to be fun, Murray
                      Message 10 of 17 , Mar 1, 2013
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                        all this over a man and a camera? i dont understand whats happening!this is supposed to be fun, Murray

                        --- In mallincam@yahoogroups.com, "topjimmy2010" <top-jimmy@...> wrote:
                        >
                        > I don't think Mark's tone was all that bad actually. I don't think he was whining. It is important though that everyone understand Rock's position. He's had to deal with a lot of crap over the last year, alot of which noone on this group has a clue about. A person can't be held in that situation for very long before they start to get frustrated and defensive, even someone as genuinely nice as Rock. I have seen enough personnally to put my trust in Rock, and I respect any position he takes on the sharing of his hard earned technical knowledge.
                        >
                        > Now everybody take a deeeeep breath...and exhale...good.
                        >
                        > Regards,
                        >
                        > Jim Thompson
                        > AbbeyRoadObservatory
                        >
                        > --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@> wrote:
                        > >
                        > > Mark,
                        > >
                        > > I think you misunderstood me.
                        > >
                        > > .........snip
                        > >
                        > >
                        > > On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.
                        > >
                        > > Rock Mallin
                        > >
                        >
                      • Rlandsboro
                        The successful man will build a strong foundation using the bricks that others throw at him. James in AZ Sent from my iPad ... [Non-text portions of this
                        Message 11 of 17 , Mar 1, 2013
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                          The successful man will build a strong foundation using the bricks that others throw at him.

                          James in AZ

                          Sent from my iPad

                          On Mar 1, 2013, at 4:38 PM, "Murray" <m.romisher@...> wrote:

                          > all this over a man and a camera? i dont understand whats happening!this is supposed to be fun, Murray
                          >
                          > --- In mallincam@yahoogroups.com, "topjimmy2010" wrote:
                          > >
                          > > I don't think Mark's tone was all that bad actually. I don't think he was whining. It is important though that everyone understand Rock's position. He's had to deal with a lot of crap over the last year, alot of which noone on this group has a clue about. A person can't be held in that situation for very long before they start to get frustrated and defensive, even someone as genuinely nice as Rock. I have seen enough personnally to put my trust in Rock, and I respect any position he takes on the sharing of his hard earned technical knowledge.
                          > >
                          > > Now everybody take a deeeeep breath...and exhale...good.
                          > >
                          > > Regards,
                          > >
                          > > Jim Thompson
                          > > AbbeyRoadObservatory
                          > >
                          > > --- In mallincam@yahoogroups.com, "MallinCam" wrote:
                          > > >
                          > > > Mark,
                          > > >
                          > > > I think you misunderstood me.
                          > > >
                          > > > .........snip
                          > > >
                          > > >
                          > > > On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.
                          > > >
                          > > > Rock Mallin
                          > > >
                          > >
                          >
                          >


                          [Non-text portions of this message have been removed]
                        • andrew crouch
                          As you will all have seen, this thread started with a quite practical question. Rock has indicated that he wishes not to discuss the underlying technical
                          Message 12 of 17 , Mar 1, 2013
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                            As you will all have seen, this thread started with a quite practical question. Rock has indicated that he wishes not to discuss the underlying technical details of the MFR5, and that's fine. I'd like to attempt to steer the question back into uncontroversial ground, and simply ask - has anyone tried (successfully or otherwise) to use the MFR5 in conjunction with a fast newtonian at about 0.3X? It would be useful to know this, certainly for me (because I don't have an MFR5 and I'm thinking of buying one), and probably for others who have thought about it as well.
                            I also appreciate that Rock does not recommend the use of the MFR5 with a newtonian, so I understand that there will be some technical trade-offs.

                            If there is some experience out there, great to hear from you, otherwise I suggest we close this thread and carry on with something more enjoyable.

                            Best wishes to all.

                            Andrew Crouch


                            --- In mallincam@yahoogroups.com, Rlandsboro <rlandsboro@...> wrote:
                            >
                            > The successful man will build a strong foundation using the bricks that others throw at him.
                            >
                            > James in AZ
                            >
                            > Sent from my iPad
                            >
                            > On Mar 1, 2013, at 4:38 PM, "Murray" <m.romisher@...> wrote:
                            >
                            > > all this over a man and a camera? i dont understand whats happening!this is supposed to be fun, Murray
                            > >
                            > > --- In mallincam@yahoogroups.com, "topjimmy2010" wrote:
                            > > >
                            > > > I don't think Mark's tone was all that bad actually. I don't think he was whining. It is important though that everyone understand Rock's position. He's had to deal with a lot of crap over the last year, alot of which noone on this group has a clue about. A person can't be held in that situation for very long before they start to get frustrated and defensive, even someone as genuinely nice as Rock. I have seen enough personnally to put my trust in Rock, and I respect any position he takes on the sharing of his hard earned technical knowledge.
                            > > >
                            > > > Now everybody take a deeeeep breath...and exhale...good.
                            > > >
                            > > > Regards,
                            > > >
                            > > > Jim Thompson
                            > > > AbbeyRoadObservatory
                            > > >
                            > > > --- In mallincam@yahoogroups.com, "MallinCam" wrote:
                            > > > >
                            > > > > Mark,
                            > > > >
                            > > > > I think you misunderstood me.
                            > > > >
                            > > > > .........snip
                            > > > >
                            > > > >
                            > > > > On second thoughts, improper tones and argumentation are done with me. Seem some wanted to crucify me upside down all the time. I'm off this list too for while, I need a break from this BS. Have fun. I have better things to do such as continue to work on cameras and new upcoming products that benefit astronomers. Attacking someone and belittle people seem to be a fun thing on the internet. Hope my reply does not upset you too much, Mark. I always had respect for you and always will.
                            > > > >
                            > > > > Rock Mallin
                            > > > >
                            > > >
                            > >
                            > >
                            >
                            >
                            > [Non-text portions of this message have been removed]
                            >
                          • glennledrew
                            I assume all of Rock s video cameras have the same flange-to-sensor spacing. If a camera had a sensor located deeper inside the camera, the result will be a
                            Message 13 of 17 , Mar 1, 2013
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                              I assume all of Rock's video cameras have the same flange-to-sensor spacing. If a camera had a sensor located 'deeper' inside the camera, the result will be a larger spacing for an attached focal reducer and a concomitantly larger reduction factor (faster resultant f/ratio.) Therefore, assuming similar sensor positioning inside the camera...

                              If, when conducting the comparison with the Meade f/3.3 reducer, the spacing for the latter was a bit less than nominal, it would have operated at a larger-than-0.33X reduction factor. Indeed, it's quite conceivable that the Meade f/3.3 unit was operating at close to 0.5X.

                              The reduction factor for a reducer depends only--or at least to a very great degree-- on the reducer's effective focal length and the spacing between the focal surface and relevant principal plane of the reducer. There could be slight differences resulting from the telescope's focal length and f/ratio, but to first order, a particular reducer at given lens-to-focus separation will provide the same focal reduction factor for all telescopes.

                              My own experience has shown that the MFR-5 on an f/5 Newt performs very well at its "native" (mo spacer) 0.5X configuration.

                              Glenn LeDrew
                              Ottawa

                              --- In mallincam@yahoogroups.com, "MallinCam" <mallincam@...> wrote:
                              >
                              > Andrew, Mark,
                              >
                              > The website site does show a comparable image using a 1996 Meade F/3.3 focal reducer and the MFR-5. When I used to grind the lenses by hands, the Meade F/3.3 older series was our model to obtain the the field of view I was looking for. Based on our optical bench at the time. The measurement were in fact F/3.3. I even got as low as F/2.9 with the MFR-5 and spacers. Problem we came up was accurate measurement on many SCT. Many SCT's do not have a dead on F /10. They varied from F/9.5 up to F/10.5. With F ratios like these on some SCT's, the actual field of view and reduction will be severely altered in the final reduction on the MFR-5 or any focal reducer for that matter.
                              >
                              > Mark, about specific measurements. I just came back from Celestron site, Meade, Orion and a handful others, and not one post there optical values on the focal reducer lens. Why should I? Our design is unique on the market and is applied only to video ccd sensors of 1/2" in size and is made to be used at close distance to the ccd sensor. I am not about to give any optical values to anyone. No one else does it, why should I disclose our hard work in design and trade secret. The Ratio is F/3.3 when tested on a Meade LX 200 16" Classic, and a new Meade LX 200 16" ACF as well. The MFR-5 is compatible to all SCT's RC's, ACF, Edge and more. I would not recommend using the MFR-5 on a Newtonian type optics. Main mirror would need to be moved up too much to achieve focus. The MFR-3 was design for a Newtonian in mind.
                              >
                              > See our website at:
                              >
                              > http://mallincam.tripod.com/sitebuildercontent/sitebuilderpictures/m2focalreducersx.jpg
                              >
                              > Website page at:
                              > http://mallincam.tripod.com/id15.html
                              >
                              > Scroll down the page and find the same as above for actual images taken with a old Meade F/3.3 focal reducer and the MFR-5 comparison.
                              >
                              >
                              > Rock M.
                              >
                              >
                              >
                              >
                              > --- In mallincam@yahoogroups.com, "Mark" <mclewis1@> wrote:
                              > >
                              > > Andrew,
                              > >
                              > > I like the way you worded that ... "MFR-5 is designed as a 0.3x focal reducer."
                              > >
                              > > It certainly was designed for that, but it's not sold that way. As it's sold on it's own it's closer to a 0.5x reducer as Glenn has mentioned. To be capable of the reduced reduction factors you need to add the optional C thread spacers.
                              > >
                              > > If Rock (or someone else who's capable of accurately measuring it) would publish the focal length of the MFR-5 in it's various configurations (with 5 and 10mm spacers) you could use the following online calculator to determine the in focus travel requirements.
                              > >
                              > > http://www.wilmslowastro.com/software/formulae.htm (scroll down to the focal reducer section).
                              > >
                              > > Mark
                              > >
                              > > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
                              > > >
                              > > > Hi Glen and thanks,
                              > > >
                              > > > My understanding is that the MFR5 is designed as a X0.3 focal reducer, so of course it would be good to be able to squeeze as much surface brightness out of it as possible. Having said that, your points are all good ones.
                              > > >
                              > > > My secondary has some unused headroom (about the outer 10mm of its 70mm short diameter), which means I lose no light around the secondary at 0.6X FR and setting back of secondary and the FR into the light cone by the measured 40mm, so one telling point would be how much further the 0.3X configuration would push it. If you or someone could tell me the diameter of the front FR element, and the additional infocus needed to run the MFR5 as a 0.3X (compared to no FR at all), I could make a stab at calculating how far I could push it without the front element causing vignetting, and without losing too much light around the secondary. Of course, as you say, aberration is a factor so I would be interested to know if anyone else has actually tried it.
                              > > >
                              > > > Cheers,
                              > > >
                              > > > Andrew
                              > > >
                              > > >
                              > > >
                              > > > --- In mallincam@yahoogroups.com, "glennledrew" <gcledrew@> wrote:
                              > > > >
                              > > > > Andrew,
                              > > > > I've used my VSS and MFR-5 on a friend's 12" collapsible Skywatcher f/4.9. He had already made up a set of spacers from PVC pipe sections which snap onto the the three poles. I didn't check to see if there was aperture reduction occurring, but given the relatively small decrease in primary-to-secondary separation, if happening it must be pretty much negligible.
                              > > > >
                              > > > > I didn't install any spacers with the reducer, and so the reduction factor, as measured directly by me, was 0.5X, yielding f/2.45.
                              > > > >
                              > > > > From a variety of examinations on a few scopes, I feel there is little to be gained by adding spacers, at least when used on faster scopes such as these Newts. Already the MFR-5 is working close to the limit, whereby the front element is not far removed from itself becoming the aperture restrictor. By adding a spacer, the front lens is pushed farther up into the light cone where it's wider. If the light cone for on-axis light becomes clipped by the now too-small lens, aperture reduction is in effect.
                              > > > >
                              > > > > One can certainly continue to install spacers if the aim is to obtain a wider field, but once aperture reduction commences, the working f/ratio remains nearly constant, and so the image surface brightness increases little, if any. And of course vignetting becomes rapidly more offensive, and optical aberrations get worse.
                              > > > >
                              > > > > You would probably be hard pressed to obtain a system speed as fast as f/2, and by that point the outer field may be getting unacceptably aberrated and vignetted.
                              > > > >
                              > > > > In my own case (12" f/2.45), from a dark site and with an Orion Skyglow Imaging filter installed, the performance was quite good with 30 second integrations, even on such faint stuff as the Bubble nebula, NGC 7635.
                              > > > >
                              > > > > --- In mallincam@yahoogroups.com, "andrew crouch" <crouch2@> wrote:
                              > > > > >
                              > > > > > I would like to hear from anyone in the group who has used an MFR5 f/3 focal reducer with a 12" or similar sized f5 newtonian to achieve around f1.7 using a 1/2" CCD video camera, and whether there are any special factors to be aware of.
                              > > > > >
                              > > > > > My newtonian is of the flextube type, so by extending the secondary cage only out to about 40mm short of its normal full extension I can obtain focus readily, at least with my current f/6 focal reducer.
                              > > > > >
                              > > > > > I am aware that by doing this there may/will be some loss of light around the edge of the secondary, so it would be good to know how far back the secondary needs to be behind its normal position to achieve focus with the MFR5.
                              > > > > >
                              > > > > > Another concern is whether there is significant distortion.
                              > > > > >
                              > > > > > Thanks,
                              > > > > >
                              > > > > > Andrew Crouch
                              > > > > >
                              > > > >
                              > > >
                              > >
                              >
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