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Re: Eyepiece Projection

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  • Jeff (also aka: StarGeezer)
    I don t think you need to over-think this, Patrick ... just go for it. You need a lot of focal length to get a decent-sized planetary image. You can start with
    Message 1 of 6 , Nov 1, 2011
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      I don't think you need to over-think this, Patrick ... just go for it. You need a lot of focal length to get a decent-sized planetary image. You can start with the Moon to have an easy way to gauge focus, then slew to Jupiter or whatever other target you have in mind.

      Uranus and Neptune are gonna cover just a few pixels, so don't expect detail unless you have a boatload of focal length. But Jupiter will be quite nice.

      If you don't have an eyepiece projection adapter, do you have any extension tubes? You can vary the image scale by changing the distance between eyepiece and camera chip, then adjust focus using the focuser.

      You can also vary the distance (and therefore image scale) by using multiple M42 adapters and changing the number of them that you use.

      You mentioned a C-mount adapter ... are you planning to use a video camera for captures? If so, and you can save the video stream as an AVI or some format that you can later convert to AVI, you can use programs like Registax to greatly improve your final result.

      You can also do this with individual frames, but it can take quite a few of them.

      Jeff B.

      --- In Stellarvue@yahoogroups.com, Patrick Wayne <pwayne@...> wrote:
      >
      > I have a question. I am planning on trying a little imaging over the holidays (Thanksgiving) and I wanted to do some planetary stuff. I don't have a barlow, or power mate for imaging, but I do have plenty of M42 extensions, an M42 to c-mount adapter, and all of my eyepieces can be used for eyepiece projection. I've never tried it before, so I was hoping someone out there could give me some advice.
      >
      > I would like to know how to calculate the correct distance from the EP lens to the CCD chip. The back focus on my camera is 19mm and all but two of my Eps have 20mm eye relief, the other two have 15mm eye relief. I don't want to set everything up just to fail at it because I don't know what I'm doing. Does anyone have some advice?
      >
      > Patrick Wayne
      > pwayne@...
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    • Patrick Wayne
      Jeff, I am going to use an Imaging Source DFK21AU618 color camera. I bought a bunch of T2 extension tubes and a T2 to C-mount adapter. My Pentax EPs have
      Message 2 of 6 , Nov 1, 2011
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        Jeff,

        I am going to use an Imaging Source DFK21AU618 color camera. I bought a bunch of T2 extension tubes and a T2 to C-mount adapter. My Pentax EPs have thread on them so that I can use an adapter and couple the camera directly to them, using the T2 extension tubes. I also have an adapter of the same type to use my Ethos EPs. It was a lot cheaper to get the adapters than to buy a couple of Powermates, or even Barlows. The glass used in the Pentax XW and Ethos eyepieces is amazing and should provide me with a beautiful image.

        The extension tubes are probably my greatest concern. Does it actually matter, focus wise, what the EP lens to chip distance is? I tried some EP Projection a while back with a Pentax XW and my DSLR with no luck, so I figured that I either needed a 2" extension tube, or the lens to chip distance wasn't correct.

        Patrick Wayne
        pwayne@...




        On Nov 1, 2011, at 1:46 PM, Jeff (also aka: StarGeezer) wrote:

        > I don't think you need to over-think this, Patrick ... just go for it. You need a lot of focal length to get a decent-sized planetary image. You can start with the Moon to have an easy way to gauge focus, then slew to Jupiter or whatever other target you have in mind.
        >
        > Uranus and Neptune are gonna cover just a few pixels, so don't expect detail unless you have a boatload of focal length. But Jupiter will be quite nice.
        >
        > If you don't have an eyepiece projection adapter, do you have any extension tubes? You can vary the image scale by changing the distance between eyepiece and camera chip, then adjust focus using the focuser.
        >
        > You can also vary the distance (and therefore image scale) by using multiple M42 adapters and changing the number of them that you use.
        >
        > You mentioned a C-mount adapter ... are you planning to use a video camera for captures? If so, and you can save the video stream as an AVI or some format that you can later convert to AVI, you can use programs like Registax to greatly improve your final result.
        >
        > You can also do this with individual frames, but it can take quite a few of them.
        >
        > Jeff B.
        >
        > --- In Stellarvue@yahoogroups.com, Patrick Wayne <pwayne@...> wrote:
        > >
        > > I have a question. I am planning on trying a little imaging over the holidays (Thanksgiving) and I wanted to do some planetary stuff. I don't have a barlow, or power mate for imaging, but I do have plenty of M42 extensions, an M42 to c-mount adapter, and all of my eyepieces can be used for eyepiece projection. I've never tried it before, so I was hoping someone out there could give me some advice.
        > >
        > > I would like to know how to calculate the correct distance from the EP lens to the CCD chip. The back focus on my camera is 19mm and all but two of my Eps have 20mm eye relief, the other two have 15mm eye relief. I don't want to set everything up just to fail at it because I don't know what I'm doing. Does anyone have some advice?
        > >
        > > Patrick Wayne
        > > pwayne@...
        > >
        > >
        > >
        > >
        > >
        > >
        > > [Non-text portions of this message have been removed]
        > >
        >
        >



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      • Jeff (also aka: StarGeezer)
        It matters, but probably less than you think since you can adjust focus using the telescope focuser ... if your T2 extensions are just adapters and not long
        Message 3 of 6 , Nov 1, 2011
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          It matters, but probably less than you think since you can adjust focus using the telescope focuser ... if your T2 "extensions" are just adapters and not long extension tubes, I feel sure you can get there.

          I know there's a way to calculate this, but given the mix of things you have going on, I'm thinking it will be way more complicated than just trying it.

          --- In Stellarvue@yahoogroups.com, Patrick Wayne <pwayne@...> wrote:
          >
          > Jeff,
          >
          > I am going to use an Imaging Source DFK21AU618 color camera. I bought a bunch of T2 extension tubes and a T2 to C-mount adapter. My Pentax EPs have thread on them so that I can use an adapter and couple the camera directly to them, using the T2 extension tubes. I also have an adapter of the same type to use my Ethos EPs. It was a lot cheaper to get the adapters than to buy a couple of Powermates, or even Barlows. The glass used in the Pentax XW and Ethos eyepieces is amazing and should provide me with a beautiful image.
          >
          > The extension tubes are probably my greatest concern. Does it actually matter, focus wise, what the EP lens to chip distance is? I tried some EP Projection a while back with a Pentax XW and my DSLR with no luck, so I figured that I either needed a 2" extension tube, or the lens to chip distance wasn't correct.
          >
          > Patrick Wayne
          > pwayne@...
          >
          >
          >
          >
          > On Nov 1, 2011, at 1:46 PM, Jeff (also aka: StarGeezer) wrote:
          >
          > > I don't think you need to over-think this, Patrick ... just go for it. You need a lot of focal length to get a decent-sized planetary image. You can start with the Moon to have an easy way to gauge focus, then slew to Jupiter or whatever other target you have in mind.
          > >
          > > Uranus and Neptune are gonna cover just a few pixels, so don't expect detail unless you have a boatload of focal length. But Jupiter will be quite nice.
          > >
          > > If you don't have an eyepiece projection adapter, do you have any extension tubes? You can vary the image scale by changing the distance between eyepiece and camera chip, then adjust focus using the focuser.
          > >
          > > You can also vary the distance (and therefore image scale) by using multiple M42 adapters and changing the number of them that you use.
          > >
          > > You mentioned a C-mount adapter ... are you planning to use a video camera for captures? If so, and you can save the video stream as an AVI or some format that you can later convert to AVI, you can use programs like Registax to greatly improve your final result.
          > >
          > > You can also do this with individual frames, but it can take quite a few of them.
          > >
          > > Jeff B.
          > >
          > > --- In Stellarvue@yahoogroups.com, Patrick Wayne <pwayne@> wrote:
          > > >
          > > > I have a question. I am planning on trying a little imaging over the holidays (Thanksgiving) and I wanted to do some planetary stuff. I don't have a barlow, or power mate for imaging, but I do have plenty of M42 extensions, an M42 to c-mount adapter, and all of my eyepieces can be used for eyepiece projection. I've never tried it before, so I was hoping someone out there could give me some advice.
          > > >
          > > > I would like to know how to calculate the correct distance from the EP lens to the CCD chip. The back focus on my camera is 19mm and all but two of my Eps have 20mm eye relief, the other two have 15mm eye relief. I don't want to set everything up just to fail at it because I don't know what I'm doing. Does anyone have some advice?
          > > >
          > > > Patrick Wayne
          > > > pwayne@
          > > >
          > > >
          > > >
          > > >
          > > >
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          > [Non-text portions of this message have been removed]
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        • Darren Hennig
          Patrick: When doing EP projection, you can use EPs with slightly shorter eye relief, but risk vignetting. The best way to evaluate the combinations are to try
          Message 4 of 6 , Nov 2, 2011
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            Patrick:

            When doing EP projection, you can use EPs with slightly shorter eye relief, but risk vignetting. The best way to evaluate the combinations are to try them before imaging, and terrestrial long distance shots (birding, etc.) are good ways to see what you think of the combination. The moon is also an excellent target to try shooting - easy to find, and lots of detail. When combined, you may find that the back focus may change somewhat with the combined imaging magnification scale and optimal focus.

            The biggest trick is to have the EP centered and aligned with the EP - Usually, the longer focal length and eye relief EPs are easier to use, and yield better results. However, long eye relief [>15mm] shorter f.l. EPs can work very well on planetary and doubles. Use the highest quality EPs you can use, as often less costly EPs can tend to add spectral artifacts [chroma] on the field edges, coma, and other aberrations. Be mindful of added weight when tracking, and ensure as solid a setup with the camera as possible! ;-)

            Darren



            [Non-text portions of this message have been removed]
          • Patrick Wayne
            Yeah, I am trying to make it as stable and solid as possible. A few of my Eps only have a 1.25 barrel, so they may become a problem. But, both my 6mm and
            Message 5 of 6 , Nov 2, 2011
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              Yeah, I am trying to make it as stable and solid as possible. A few of my Eps only have a 1.25" barrel, so they may become a problem. But, both my 6mm and 10mm Ethos' should work well.

              Patrick Wayne
              pwayne@...




              On Nov 2, 2011, at 8:16 AM, Darren Hennig wrote:

              > Patrick:
              >
              > When doing EP projection, you can use EPs with slightly shorter eye relief, but risk vignetting. The best way to evaluate the combinations are to try them before imaging, and terrestrial long distance shots (birding, etc.) are good ways to see what you think of the combination. The moon is also an excellent target to try shooting - easy to find, and lots of detail. When combined, you may find that the back focus may change somewhat with the combined imaging magnification scale and optimal focus.
              >
              > The biggest trick is to have the EP centered and aligned with the EP - Usually, the longer focal length and eye relief EPs are easier to use, and yield better results. However, long eye relief [>15mm] shorter f.l. EPs can work very well on planetary and doubles. Use the highest quality EPs you can use, as often less costly EPs can tend to add spectral artifacts [chroma] on the field edges, coma, and other aberrations. Be mindful of added weight when tracking, and ensure as solid a setup with the camera as possible! ;-)
              >
              > Darren
              >
              > [Non-text portions of this message have been removed]
              >
              >



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