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RCX400 Focusing question

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  • kinetoplast2000
    Hi guys I have a 10 inch RCX400 for several years now and have had really good imaging with it, once I learned how. I use an AO-8 and a Pyxis Rotator to find
    Message 1 of 7 , Apr 9 11:22 PM
      Hi guys

      I have a 10 inch RCX400 for several years now and have had really good imaging with it, once I learned how. I use an AO-8 and a Pyxis Rotator to find guide stars for my SBIG ST2000XCM CCD. I use ACP to control the scope and Maxim to control the CCD, and PemPro to remove PE. When I first started, I had Dr. Clay do a "Supercharge" and that made all the difference in the world.

      My question is how do others with this telescope do automatic focusing (if at all)? The focusing of course is electronic and I fortunately find it is really stable. I can set the focus for an entire night and it pretty much stays in focus. But I would like to use automatic focusing with Focusmax in ACP. I once tried inserting a Crayford focuser into the visual train and using Robofocus, but it put too much weight on the train and I got rid of it.

      The other problem I have is that I cannot image almost half of what I want to since there is no bright enough guide star (mag 10 or brighter) available. I see no way around this with my setup, but perhaps someone has a good idea. I tried setting up an external guide scope piggy backed to the RCX, but there was too much flexion and I went back to the internal guide chip system.

      My last question is how can I remove the accumulated dust et al from the mirror? Is there a trustworthy service that can do this for a charge?

      All in all I have been very satisfied with this telescope.

      Larry Simpson
    • Steve C. Mitchell, Sr.
      Hey Larry,
      Message 2 of 7 , Apr 10 1:26 PM

        Hey Larry,

         

        <<<<< I have a 10 inch RCX400 for several years now and have had really good imaging with it, once I learned how. I use an AO-8 and a Pyxis Rotator to find guide stars for my SBIG ST2000XCM CCD. I use ACP to control the scope and Maxim to control the CCD, and PemPro to remove PE. When I first started, I had Dr. Clay do a "Supercharge" and that made all the difference in the world.>>>>

         

        I have a 12” RCX and love it, they are excellent scopes, but you are right you have to get to know them in order to use them to their fullest extent. I have not graduated to ACP (yet) and I use Nebulosity to control my scope, so my set up is different than yours, but there are still similarities. Dr. Clay’s Supercharge was also done to my scope and I also believe he added a great deal of functionality to it as well.

         

        <<<<< My question is how do others with this telescope do automatic focusing (if at all)? The focusing of course is electronic and I fortunately find it is really stable. I can set the focus for an entire night and it pretty much stays in focus. But I would like to use automatic focusing with Focusmax in ACP. I once tried inserting a Crayford focuser into the visual train and using Robofocus, but it put too much weight on the train and I got rid of it.>>>>

         

        I don’t believe it is possible to do automatic focusing with the built in focuser on the RCX. Meade won’t share their code for it, that is why Ajay gave up on his ASCOM driver for the scope several years ago. The only option I am aware of for auto focus would be an external focuser on the visual back, which you said you already tried and have abandoned. Robotic focusing, still done manually not automatically, CAN be done by using Meade’s  remote handbox, but you have to be there to do it yourself. I am still contemplating the visual back focuser myself, you would need to counter weight the front of the scope for balance, which can for the most part be taken care of with an aluminum dew shield and a 2D balancing system.

        OTOH I find the focuser also seems to hold focus quite well over a nights imaging too.

         

         

        <<<<The other problem I have is that I cannot image almost half of what I want to since there is no bright enough guide star (mag 10 or brighter) available. I see no way around this with my setup, but perhaps someone has a good idea. I tried setting up an external guide scope piggy backed to the RCX, but there was too much flexion and I went back to the internal guide chip system.>>>>

         

        An external guide scope is most definitely doable! I have a Meade 80mm ED APO piggybacked on mine using Anthony’s excellent ADM dovetail’s, one on top for his also excellent mounting rings and one on the bottom for his 2D balancing system. Not all that expensive and WELL worth the cost in what they do for your overall happiness and sanity with your setup! I have not detected any flexure in my system at all, it is capable of at least 30 minute subs with virtually round stars and could probably do more.

         

        <<<<< My last question is how can I remove the accumulated dust et al from the mirror? Is there a trustworthy service that can do this for a charge?>>>>>

         

        I have not looked for anyone to do this for me, but I’m sure somebody knows someone, besides Meade, that will. Meade will be happy to do so, but I believe they have a flat charge for service no matter what they do to the scope, plus shipping both ways and weeks if not months of down time. It really isn’t that hard to take care of this yourself in a few hours if you have ANY DIY skills, common sense and good blood pressure! Dr. Clay will probably frown on my suggestion, but do it yourself! There are literally only six screws holding the corrector plate on and the plug for the dew heater and it’s off! Have a nice clean, safe place ready before you remove it and lay it down carefully on some clean cotton towels, sheets, blankets, etc.! Be very careful with it, it will NOT be a cheap or easy replacement if you break or scratch it!!!!!!! Definitely doable again though! The mirror is then exposed at the bottom of the tube and with the scope pointed slightly downward so no chance of anything going back towards the back of the scope, lay a clean cotton “T-towel” or equivalent, in the bottom of the tube and carefully follow Doc Clay’s instructions for cleaning the mirror. They can be found on his website at:  http://www.arksky.org/asoclean.htm  While you’re this far along, clean the corrector plate and secondary mirror if they need it too, after all, you’re already in there! Remember, these things don’t need to be done very often at all, quite a few spots and dust on the corrector plate, main and secondary mirrors don’t even show up on the image in most cases and you do take a chance of damaging your coatings. Most of your dust motes are actually on either filters, lens cover or actually on the chip as they are much closer to the actual image and therefore are big enough to show. Dust and spots on the mirror cut down overall brightness, but are so far away from the chip that they have a hard time actually showing up in the image. I have had my scope since 2006 and cleaned it shortly after getting it (it was used) and haven’t cleaned sit since, but I am contemplating it again as it is getting quite a bit of “stuff” gathered on it.

        Oh yea, putting the corrector plate back on an RCX is a “no brainer”, I have heard untrue stories about putting it back on in the wrong orientation and ruining the optics of the scope, perhaps with the LX200GPS and other scopes without the focusable corrector this is possible, but the RCX has the dew heater plug and there is only one possible way to put the corrector back on and still plug it in, so……. “no brainer”. Remember to just snug the screws down, DON”T over tighten them as you will likely crack your corrector!

         

        I am not saying this is for everyone, but for those with reasonable DIY skills and a lot of common sense, there really isn’t that much to it, after all, it isn’t rocket science! 8>)

        I’m sure some will think that I have gone out on a limb here with this advise, but I truly believe a person can and should take care of as much stuff as he can all by himself! Daddy always told me it I was looking for a helping hand the best place to find one was to look at the end of my own arm! Excellent advise in my book! Thanks Dad!

         

        HTH,

         

        Steve

         

        Stephen C. Mitchell, Sr., O.D.

        Scopehill Observatory

        www.Scopehill.com

         

         


      • Southern Stars Observatories
        ... It is possible, and we have used it for years with our RCX 14 and 16 . Jean-Claude PELLE Southern Stars Observatories
        Message 3 of 7 , Apr 10 4:13 PM
          > I don't believe it is possible to do automatic focusing with the
          > built in focuser on the RCX.

          It is possible, and we have used it for years with our RCX 14" and 16".


          Jean-Claude PELLE
          Southern Stars Observatories
        • Steven Elliott
          I bought a feathertouch focuser and mounted it on the RCX optical back, eliminating the need to use the RCX focuser, and can remote focus thru FocusMax. It s
          Message 4 of 7 , Apr 10 4:38 PM
            I bought a feathertouch focuser and mounted it on the RCX optical back, eliminating the need to use the RCX focuser, and can remote focus thru FocusMax. It's definitely the best way to go. It elimiantes any focus runaway dangers, and you can stay nice and warm between filter changes! ALso when you set collimation, you only have to do it once and forget it forever, because constant focusing necessitates it unless you use an outside focuser.
            Steve
             

            To: RCX400@yahoogroups.com
            From: jcpelle@...
            Date: Sun, 10 Apr 2011 23:13:59 +0000
            Subject: RE: [RCX400] RCX400 Focusing question

             
            > I don't believe it is possible to do automatic focusing with the
            > built in focuser on the RCX.

            It is possible, and we have used it for years with our RCX 14" and 16".

            Jean-Claude PELLE
            Southern Stars Observatories


          • Steve C. Mitchell, Sr.
            Hey Jean-Claude, New information is always welcome! How do you go about auto focusing the internal focuser on the RCX? I ve never heard of anyone else doing
            Message 5 of 7 , Apr 10 9:04 PM
              Hey Jean-Claude,
               
              New information is always welcome! How do you go about auto focusing the internal focuser on the RCX? I've never heard of anyone else doing it, it's always been an external focuser such as the Feather Touch..
               
              Steve
               
              Stephen C. Mitchell, Sr., O.D.
              Scopehill Observatory
              12", RCX400
               


              From: RCX400@yahoogroups.com [mailto:RCX400@yahoogroups.com] On Behalf Of Southern Stars Observatories
              Sent: Sunday, April 10, 2011 6:14 PM
              To: RCX400@yahoogroups.com
              Subject: RE: [RCX400] RCX400 Focusing question

               

              > I don't believe it is possible to do automatic focusing with the
              >

              built in focuser on the RCX.

              It is possible, and we have used it for years with our RCX 14" and 16".

              Jean-Claude PELLE
              Southern Stars Observatories

            • kinetoplast2000
              Hi Jean-Claude I would be very interested in learning how to do automatic focusing with my RCX. That would really be great. Larry
              Message 6 of 7 , Apr 12 8:24 AM
                Hi Jean-Claude

                I would be very interested in learning how to do automatic focusing with my RCX. That would really be great.

                Larry

                --- In RCX400@yahoogroups.com, Steven Elliott <steven447@...> wrote:
                >
                >
                > I bought a feathertouch focuser and mounted it on the RCX optical back, eliminating the need to use the RCX focuser, and can remote focus thru FocusMax. It's definitely the best way to go. It elimiantes any focus runaway dangers, and you can stay nice and warm between filter changes! ALso when you set collimation, you only have to do it once and forget it forever, because constant focusing necessitates it unless you use an outside focuser.
                > Steve
                >
                >
                >
                > To: RCX400@yahoogroups.com
                > From: jcpelle@...
                > Date: Sun, 10 Apr 2011 23:13:59 +0000
                > Subject: RE: [RCX400] RCX400 Focusing question
                >
                >
                >
                >
                >
                >
                > > I don't believe it is possible to do automatic focusing with the
                > > built in focuser on the RCX.
                >
                > It is possible, and we have used it for years with our RCX 14" and 16".
                >
                > Jean-Claude PELLE
                > Southern Stars Observatories
                >
              • Steven Elliott
                Larry, When you set up FocusMax for the first time, it automatically focuses and plots the focus to the sharpest image possible. It then uses that as a
                Message 7 of 7 , Apr 12 2:01 PM
                  Larry,
                  When you set up FocusMax for the first time, it automatically focuses and plots the focus to the sharpest image possible. It then uses that as a benchmark for next time you focus, or next viewing session, and re-focus for each subsequent session is a piece of cake. You ought to try it - I never heard anyone using this complain. It can do what you want it to do, and easily, and not a steep learning curve - just a steep "i can hardly believe it' curve.
                  Have fun,
                  Steve
                   

                  To: RCX400@yahoogroups.com
                  From: larrys3255@...
                  Date: Tue, 12 Apr 2011 15:24:38 +0000
                  Subject: [RCX400] Re: RCX400 Focusing question

                   
                  Hi Jean-Claude

                  I would be very interested in learning how to do automatic focusing with my RCX. That would really be great.

                  Larry

                  --- In RCX400@yahoogroups.com, Steven Elliott <steven447@...> wrote:
                  >
                  >
                  > I bought a feathertouch focuser and mounted it on the RCX optical back, eliminating the need to use the RCX focuser, and can remote focus thru FocusMax. It's definitely the best way to go. It elimiantes any focus runaway dangers, and you can stay nice and warm between filter changes! ALso when you set collimation, you only have to do it once and forget it forever, because constant focusing necessitates it unless you use an outside focuser.
                  > Steve
                  >
                  >
                  >
                  > To: RCX400@yahoogroups.com
                  > From: jcpelle@...
                  > Date: Sun, 10 Apr 2011 23:13:59 +0000
                  > Subject: RE: [RCX400] RCX400 Focusing question
                  >
                  >
                  >
                  >
                  >
                  >
                  > > I don't believe it is possible to do automatic focusing with the
                  > > built in focuser on the RCX.
                  >
                  > It is possible, and we have used it for years with our RCX 14" and 16".
                  >
                  > Jean-Claude PELLE
                  > Southern Stars Observatories
                  >


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