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ETX-80 Problem aligning

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  • Chip Frappier
    Hey Gang, Need a little help with aligning an ETX-80. A new member of our club has bought an ETX-80 for his 9 year old son and to date he has been unable to
    Message 1 of 20 , Jun 6, 2007
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      Hey Gang,

      Need a little help with aligning an ETX-80. A new member of our club
      has bought an ETX-80 for his 9 year old son and to date he has been
      unable to align the scope. We tried the other night, leveled the
      tube and pointed due north. Tried a two-star on Vega and then
      Pollux. Scope slewed right towards Vega but kept going, stopping
      about 20 deg south of vega. Centered Vega and tried for Pollux.
      Scope slewed left and went past Pollux about 30 deg. Dec has been
      close, RA way off.
      Checked all settings (date, time, location, DST) all ok.
      Tried again with tripod handle facing south, leveled tube and scope
      pointing north. This time picked Vega and got it in the eyepiece
      (minor RA adj to center). When we went for Pollux, same thing, about
      30 deg too far south (alignment failed)!!!!
      Any ideas, hints, tips or do we have a bad one. Thought about doing
      a reset and starting from scratch (re enter all info, retrain drives)
      yes/no?

      Thanks for your time!

      Chip
    • rmollise@bellsouth.net
      Hi: If a good drive training was done, there s no need to revisit that...and yet... There are not too many things that can cause this behavior. One is poor
      Message 2 of 20 , Jun 7, 2007
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        Hi:

        If a good drive training was done, there's no need to revisit that...and yet...

        There are not too many things that can cause this behavior. One is poor power. If running off internal batteries make sure they are fresh. Forget rechargeable ones.

        What happens if you go ahead and center the alignment star that's been "missed"? They need not be in the eyepiece. (4 or 5 degrees off is more common)

        Unk Rod
        >
        > From: "Chip Frappier" <dafuzz_9@...>
        > Date: 2007/06/06 Wed PM 10:59:51 CDT
        > To: ETXASTRO@yahoogroups.com
        > Subject: [ETXASTRO] ETX-80 Problem aligning
        >
        > Hey Gang,
        >
        > Need a little help with aligning an ETX-80. A new member of our club
        > has bought an ETX-80 for his 9 year old son and to date he has been
        > unable to align the scope. We tried the other night, leveled the
        > tube and pointed due north. Tried a two-star on Vega and then
        > Pollux. Scope slewed right towards Vega but kept going, stopping
        > about 20 deg south of vega. Centered Vega and tried for Pollux.
        > Scope slewed left and went past Pollux about 30 deg. Dec has been
        > close, RA way off.
        > Checked all settings (date, time, location, DST) all ok.
        > Tried again with tripod handle facing south, leveled tube and scope
        > pointing north. This time picked Vega and got it in the eyepiece
        > (minor RA adj to center). When we went for Pollux, same thing, about
        > 30 deg too far south (alignment failed)!!!!
        > Any ideas, hints, tips or do we have a bad one. Thought about doing
        > a reset and starting from scratch (re enter all info, retrain drives)
        > yes/no?
        >
        > Thanks for your time!
        >
        > Chip
        >
        >
        >
      • autostaretx
        ... A Reset is always a good idea for weird behaviour... and you probably don t -need- to do a Train afterwards to see if a twenty-degree error has occurred.
        Message 3 of 20 , Jun 7, 2007
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          --- In ETXASTRO@yahoogroups.com, "Chip Frappier" <dafuzz_9@...> wrote:
          >
          > Hey Gang,
          >
          > Need a little help with aligning an ETX-80. A new member of our club
          > has bought an ETX-80 for his 9 year old son and to date he has been
          > unable to align the scope. We tried the other night, leveled the
          > tube and pointed due north. Tried a two-star on Vega and then
          > Pollux. Scope slewed right towards Vega but kept going, stopping
          > about 20 deg south of vega. Centered Vega and tried for Pollux.
          > Scope slewed left and went past Pollux about 30 deg. Dec has been
          > close, RA way off.
          > Checked all settings (date, time, location, DST) all ok.
          > Tried again with tripod handle facing south, leveled tube and scope
          > pointing north. This time picked Vega and got it in the eyepiece
          > (minor RA adj to center). When we went for Pollux, same thing, about
          > 30 deg too far south (alignment failed)!!!!
          > Any ideas, hints, tips or do we have a bad one. Thought about doing
          > a reset and starting from scratch (re enter all info, retrain
          > drives) yes/no?

          A Reset is always a good idea for weird behaviour... and you
          probably don't -need- to do a Train afterwards to see if a
          twenty-degree error has occurred.

          As Unk Rod said, the first thing to try are fresh batteries.
          In -any- case (fresh or not):
          What you *do* want to do after the Reset is a "Calibrate Motors".
          That tunes the internal encoder illumination to match the system.

          I'm glad you gave your report of the -second- attempt (where it
          got Vega OK), because that completely bypasses the "wrong time
          of day" issue.
          But what may be -physically- wrong is that dirt or thrown
          grease may be affecting the Az (RA) encoder.
          You can test for that (After the fresh batteries and Calibrate)
          by aiming at a landmark (you can point the scope there and
          -then- power up). After getting past the date/time prompts,
          lean on the [mode] key for 3 seconds. Release.
          That should bring up the RA/DEC display.
          Scroll down once, that brings up the Alt/Az display (which will
          be all zeros if done before aligning).
          Now, use the slew key to spin the scope -completely- around to
          recenter the landmark (thus a full 360 degree spin).
          Read the Autostar's readout.

          If it shows markedly (i.e. more than a degree) less than 360 degrees
          of travel (on my ETX90 i'd see exactly 350 given this fault),
          then that's almost a 100% sure sign of one encoder vane being "dirty"
          (occluded).

          The fix is to open the base and clean it (which may be difficult
          on an ETX80, i've never tried with that model),
          or return the scope for exchange.

          If the complete-spin shows -random- results (sometimes 3 degrees
          shy, sometimes exact, sometimes 6 degrees shy) then it's a hint
          of a loose gear. Exchange.

          good luck
          --dick
        • dobdave1
          ..unable to align the scope.... Thought about doing ... Chip, Fresh batteries are a must! Make sure the location is correct, and see if it s set on correct
          Message 4 of 20 , Jun 7, 2007
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            ..unable to align the scope.... Thought about doing
            > a reset and starting from scratch (re enter all info, retrain drives)
            > yes/no?

            Chip,
            Fresh batteries are a must! Make sure the location is correct, and see
            if it's set on correct time as well as daylight savings time. If it
            checks out OK, do a reset, re-train the drives, and re-enter time,
            date, and location. Be shure the scope base and the tube are both
            level and pointing North.
            Good luck, Dave Castillo
          • rmollise@bellsouth.net
            Let me add that if nothing else helps, it s always good to: Reset Calibrate (motors) Train drive. Unk Rod
            Message 5 of 20 , Jun 7, 2007
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              Let me add that if nothing else helps, it's always good to:

              Reset
              Calibrate (motors)
              Train drive.

              Unk Rod

              >
              > From: rmollise@... <rmollise@...>
              > Date: 2007/06/07 Thu AM 10:42:37 CDT
              > To: <ETXASTRO@yahoogroups.com>
              > Subject: Re: [ETXASTRO] ETX-80 Problem aligning
              >
              > Hi:
              >
              > If a good drive training was done, there's no need to revisit that...and yet...
              >
              > There are not too many things that can cause this behavior. One is poor power. If running off internal batteries make sure they are fresh. Forget rechargeable ones.
              >
              > What happens if you go ahead and center the alignment star that's been "missed"? They need not be in the eyepiece. (4 or 5 degrees off is more common)
              >
              > Unk Rod
              > >
              > > From: "Chip Frappier" <dafuzz_9@...>
              > > Date: 2007/06/06 Wed PM 10:59:51 CDT
              > > To: ETXASTRO@yahoogroups.com
              > > Subject: [ETXASTRO] ETX-80 Problem aligning
              > >
              > > Hey Gang,
              > >
              > > Need a little help with aligning an ETX-80. A new member of our club
              > > has bought an ETX-80 for his 9 year old son and to date he has been
              > > unable to align the scope. We tried the other night, leveled the
              > > tube and pointed due north. Tried a two-star on Vega and then
              > > Pollux. Scope slewed right towards Vega but kept going, stopping
              > > about 20 deg south of vega. Centered Vega and tried for Pollux.
              > > Scope slewed left and went past Pollux about 30 deg. Dec has been
              > > close, RA way off.
              > > Checked all settings (date, time, location, DST) all ok.
              > > Tried again with tripod handle facing south, leveled tube and scope
              > > pointing north. This time picked Vega and got it in the eyepiece
              > > (minor RA adj to center). When we went for Pollux, same thing, about
              > > 30 deg too far south (alignment failed)!!!!
              > > Any ideas, hints, tips or do we have a bad one. Thought about doing
              > > a reset and starting from scratch (re enter all info, retrain drives)
              > > yes/no?
              > >
              > > Thanks for your time!
              > >
              > > Chip
              > >
              > >
              > >
              >
              >
              >
            • Chip Frappier
              ... drives) ... see ... it ... Thanks for the replies and we will try each and every suggestion. I have forwarded your kind replies to our new member so these
              Message 6 of 20 , Jun 7, 2007
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                --- In ETXASTRO@yahoogroups.com, "dobdave1" <david.castillo1@...>
                wrote:
                >
                > ..unable to align the scope.... Thought about doing
                > > a reset and starting from scratch (re enter all info, retrain
                drives)
                > > yes/no?
                >
                > Chip,
                > Fresh batteries are a must! Make sure the location is correct, and
                see
                > if it's set on correct time as well as daylight savings time. If
                it
                > checks out OK, do a reset, re-train the drives, and re-enter time,
                > date, and location. Be shure the scope base and the tube are both
                > level and pointing North.
                > Good luck, Dave Castillo
                >
                Thanks for the replies and we will try each and every suggestion. I
                have forwarded your kind replies to our new member so these
                suggestions can be applied. I will report back with the results.
                Thanks again!

                Chip
              • Bob Dennis
                Hi Have you checked your lat/long Bob _________________________________________________________________ Play your part in making history - Email Britain!
                Message 7 of 20 , Jun 8, 2007
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                  Hi Have you checked your lat/long



                  Bob

                  _________________________________________________________________
                  Play your part in making history - Email Britain!
                  http://www.emailbritain.co.uk/
                • George Cushing
                  ... If out of warranty this scope comes apart about the same as the ETX60 and 70. After removing the RA clutch lever, back off the axle bolt about one turn to
                  Message 8 of 20 , Jun 11, 2007
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                    --- In ETXASTRO@yahoogroups.com, "autostaretx" <rseymour@...> wrote:
                    >
                    > The fix is to open the base and clean it (which may be difficult
                    > on an ETX80, i've never tried with that model),
                    > or return the scope for exchange.
                    >
                    > If the complete-spin shows -random- results (sometimes 3 degrees
                    > shy, sometimes exact, sometimes 6 degrees shy) then it's a hint
                    > of a loose gear. Exchange.
                    >
                    > good luck
                    > --dick
                    >
                    If out of warranty this scope comes apart about the same as the ETX60
                    and 70. After removing the RA clutch lever, back off the axle bolt
                    about one turn to remove the bottom thrust plate, bearing and washer.
                    Then use a properly sized socket to remove the plastic nut. Be careful
                    here, it's got some adhesive holding it in place. Once the nut's off
                    the rest is pretty easy. Got some photos if they will help.
                    George
                  • Henry Frappier
                    George, I may need those pictures. I have learned from from friend with the scope (Tom), that he did have fresh batteries installed and that it is, out of
                    Message 9 of 20 , Jun 12, 2007
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                      George,
                       
                      I may need those pictures. I have learned from from friend with the scope (Tom), that he did have fresh batteries installed and that it is, out of warranty. I believe that it may have as suggested, a loose gear or grease slung inside. I am awaiting word from Tom to see if he has made any progress and a night when he and I can get together. Tom has the worst work schedule (he works nights). I have promised to keep this group appraised of our progress and findings. A BIG THANK YOU to all who have helped, so far!
                       
                      Chip


                      Pinpoint customers who are looking for what you sell.
                    • George Cushing
                      ... scope (Tom), that he did have fresh batteries installed and that it is, out of warranty. I believe that it may have as suggested, a loose gear or grease
                      Message 10 of 20 , Jun 13, 2007
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                        --- In ETXASTRO@yahoogroups.com, Henry Frappier <dafuzz_9@...> wrote:
                        >
                        > George,
                        >
                        > I may need those pictures. I have learned from from friend with the
                        scope (Tom), that he did have fresh batteries installed and that it is,
                        out of warranty. I believe that it may have as suggested, a loose gear
                        or grease slung inside. I am awaiting word from Tom to see if he has
                        made any progress and a night when he and I can get together. Tom has
                        the worst work schedule (he works nights). I have promised to keep this
                        group appraised of our progress and findings. A BIG THANK YOU to all
                        who have helped, so far!
                        >
                        > Chip
                        >
                        OK, I put some pics in a photo album called Cushing. Look at the ETX80
                        shots. Don't let the pics scare you. You don't have to tear it down
                        completely to do what you want. I had to replace the control panel in
                        the fork arm and this requires almost a complete tear down. If you have
                        any questions let me know. HTH, Geo.
                      • Chip Frappier
                        Hey Everybody, As promised, I can now report on this problem and I believe it s cure. A momentarily clear night and enough time off from work, we attacked this
                        Message 11 of 20 , Jul 1 6:06 AM
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                          Hey Everybody,

                          As promised, I can now report on this problem and I believe it's cure.
                          A momentarily clear night and enough time off from work, we attacked
                          this problem with the suggestions of this group. Although we had to
                          perform this procedure three times in succession, the Calibrate Motors
                          routine seems to have worked. After the third attempt and subsequent
                          alignment, the alignment stars fell in the eyepiece field of view. A
                          slew to the moon was not impressive, but close enough. A slew to Venus
                          to observe the close pairing with Saturn was dead on.
                          Thank You ever so much for your kind assistance. I now have a Father
                          with a nine year old Son who is extatic about his telescope.
                          I do have one final question, does this Calibrate Motors routine have
                          to be performed with any regularity or only as needed?
                          Thanks again;

                          Chip
                        • Rod Mollise
                          Hi: Calibrate motors only needs to be performed when you change batteries. Remember, alignment stars don t have to be in the field of the eyepiece in order
                          Message 12 of 20 , Jul 1 6:44 AM
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                            Hi:
                             
                            "Calibrate motors" only needs to be performed when you change batteries.
                             
                            Remember, alignment stars don't have to be in the field of the eyepiece in order to complete a good alignment. If they are not, simply center them.
                             

                            Peace,
                            Rod Mollise
                            Author of Choosing and Using a Schmidt Cassegrain Telescope...and...
                            The Urban Astronomer's Guide
                            <http://skywatch.brainiac.com/astroland>



                            From: ETXASTRO@yahoogroups.com [mailto:ETXASTRO@yahoogroups.com] On Behalf Of Chip Frappier
                            Sent: Sunday, July 01, 2007 8:06 AM
                            To: ETXASTRO@yahoogroups.com
                            Subject: [ETXASTRO] RE: ETX-80 Problem aligning

                            Hey Everybody,

                            As promised, I can now report on this problem and I believe it's cure.
                            A momentarily clear night and enough time off from work, we attacked
                            this problem with the suggestions of this group. Although we had to
                            perform this procedure three times in succession, the Calibrate Motors
                            routine seems to have worked. After the third attempt and subsequent
                            alignment, the alignment stars fell in the eyepiece field of view. A
                            slew to the moon was not impressive, but close enough. A slew to Venus
                            to observe the close pairing with Saturn was dead on.
                            Thank You ever so much for your kind assistance. I now have a Father
                            with a nine year old Son who is extatic about his telescope.
                            I do have one final question, does this Calibrate Motors routine have
                            to be performed with any regularity or only as needed?
                            Thanks again;

                            Chip

                          • autostaretx
                            ... For validating alignments, the only true tests are stars. The planets and moons are calculated from orbital parameters, and the Autostar will induce
                            Message 13 of 20 , Jul 1 8:23 AM
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                              --- In ETXASTRO@yahoogroups.com, "Chip Frappier" <dafuzz_9@...> wrote:
                              >
                              > Hey Everybody,
                              >
                              > As promised, I can now report on this problem and I believe it's
                              > cure.
                              > A momentarily clear night and enough time off from work, we attacked
                              > this problem with the suggestions of this group. Although we had to
                              > perform this procedure three times in succession, the Calibrate
                              > Motors routine seems to have worked. After the third attempt and
                              > subsequent alignment, the alignment stars fell in the eyepiece
                              > field of view. A slew to the moon was not impressive, but close
                              > enough. A slew to Venus
                              > to observe the close pairing with Saturn was dead on.

                              For validating alignments, the only true tests are stars.
                              The planets and moons are calculated from orbital parameters,
                              and the Autostar will induce periodic errors... there will be
                              nights when the moon is spot-on, and others where it's far off.
                              But GoTo'ing the stars is what measures alignment quality.

                              That said, i'm puzzled that it took 3 times for Cal Motors to
                              finally appear to "hit the spot"... the process used internally
                              doesn't use "history" (it doesn't remember what happened last
                              time), so i suspect something (a spot of thrown grease on the
                              encoder?) is causing it to have a wide range of results, and
                              you finally caught a "good" one.

                              In which case: do NOT do another Cal Motors until the GoTo's
                              and tracking seem to be bad again.


                              > Thank You ever so much for your kind assistance. I now have a Father
                              > with a nine year old Son who is extatic about his telescope.
                              > I do have one final question, does this Calibrate Motors routine
                              > have to be performed with any regularity or only as needed?

                              Only when needed, and even then i usually wait until i get a
                              "Motor Unit Failure" message from the Autostar.

                              I still have an underlying uneasiness that something -else- may
                              be amiss, but if it continues to operate properly, then the
                              proof is certainly in the pudding.

                              have fun
                              --dick
                            • Joe Lalumia
                              ... get outside(with my external 12volt power pack). Only once.......as Uncle Rod & Dick have said it s OK to slew the scope to center the alignment
                              Message 14 of 20 , Jul 6 1:03 PM
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                                --- In ETXASTRO@yahoogroups.com, "autostaretx" <rseymour@...> wrote:
                                >On my ETX90 I usually perform a CALIBRATE motors first thing after I
                                get outside(with my external 12volt power pack). Only once.......as
                                Uncle Rod & Dick have said it's OK to slew the scope to center the
                                alignment star........in fact this is usually what needs to be done.
                                Joe Lalumia



                                >
                                >
                              • Vidgamer
                                OK, I remember a long time ago, someone was selling an 80mm lens upgrade for the ETX-60 -- did anything become of that? I haven t used the ol ETX-60 in a
                                Message 15 of 20 , Jul 7 5:52 AM
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                                   OK, I remember a long time ago, someone was selling an 80mm lens upgrade for the ETX-60 -- did anything become of that? 
                                   
                                  I haven't used the ol' ETX-60 in a while, so I'm also wondering if it's worth trying to update the internal settings; last time I tried, I think it was too much of a hassle, and I probably just lived with what was there, but it's been too long for me to recall.  I did recalibrate, and I don't know if I ever got the slew right on  :-(  so maybe I'll go through that again.
                                   
                                  Anyway, I guess I wondered if there was anything I missed in the past couple of years that I should look into.
                                   
                                  I think the best "upgrade" will be a level & compass to help set it up!  For some reason, it takes me a while to get going....
                                • Rod Mollise
                                  Hi: I don t know about an 80mm lens upgrade, but one would be more trouble than it s worth. I don t know what you mean by update the internal settings. If
                                  Message 16 of 20 , Jul 7 5:58 AM
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                                    Hi:
                                     
                                    I don't know about an 80mm lens upgrade, but one would be more trouble than it's worth.
                                     
                                    I don't know what you mean by "update the internal settings." If you mean the software, Meade has never released an update for the 60.
                                     

                                    Peace,
                                    Rod Mollise
                                    Author of Choosing and Using a Schmidt Cassegrain Telescope...and...
                                    The Urban Astronomer's Guide
                                    <http://skywatch.brainiac.com/astroland>



                                    From: ETXASTRO@yahoogroups.com [mailto:ETXASTRO@yahoogroups.com] On Behalf Of Vidgamer
                                    Sent: Saturday, July 07, 2007 7:53 AM
                                    To: ETXASTRO@yahoogroups.com
                                    Subject: [ETXASTRO] ETX-60 enhancements?

                                     OK, I remember a long time ago, someone was selling an 80mm lens upgrade for the ETX-60 -- did anything become of that? 
                                     
                                    I haven't used the ol' ETX-60 in a while, so I'm also wondering if it's worth trying to update the internal settings; last time I tried, I think it was too much of a hassle, and I probably just lived with what was there, but it's been too long for me to recall.  I did recalibrate, and I don't know if I ever got the slew right on  :-(  so maybe I'll go through that again.
                                     
                                    Anyway, I guess I wondered if there was anything I missed in the past couple of years that I should look into.
                                     
                                    I think the best "upgrade" will be a level & compass to help set it up!  For some reason, it takes me a while to get going....

                                  • daniela daniela
                                    Perhaps you mean the wo apograde, but that is not for the etx-60, it is for (many not all) refractors with a front lens of 80mm (and appropriate threads etc
                                    Message 17 of 20 , Jul 7 1:22 PM
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                                      Perhaps you mean the wo apograde, but that is not for the etx-60, it
                                      is for (many not all) refractors with a front lens of 80mm (and
                                      appropriate threads etc etc). Search for apograde and you'll find the
                                      info.
                                    • George Cushing
                                      ... trouble than ... you mean ... The 60 and the 70 are the same tube assembly and a 60 can be easily changed to a 70 with the right objective and retaining
                                      Message 18 of 20 , Jul 11 6:17 AM
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                                        --- In ETXASTRO@yahoogroups.com, "Rod Mollise" <rmollise@...> wrote:
                                        >
                                        > Hi:
                                        >
                                        > I don't know about an 80mm lens upgrade, but one would be more
                                        trouble than
                                        > it's worth.
                                        >
                                        > I don't know what you mean by "update the internal settings." If
                                        you mean
                                        > the software, Meade has never released an update for the 60.
                                        >
                                        > Peace,
                                        > Rod Mollise
                                        > Author of Choosing and Using a Schmidt Cassegrain Telescope...and...
                                        > The Urban Astronomer's Guide
                                        > <http://skywatch.brainiac.com/astroland>
                                        >
                                        > OK, I remember a long time ago, someone was selling an 80mm lens
                                        > upgrade for the ETX-60 -- did anything become of that?
                                        >
                                        The 60 and the 70 are the same tube assembly and a 60 can be easily
                                        changed to a 70 with the right objective and retaining ring. The 80
                                        is a different assembly. Due to the weight of the 80mm objective the
                                        mount has a counter balancing spring in the left fork. I don't think
                                        you could even put the whole OTA on a 60 mount successfully. HTH
                                        George
                                      • dobdave1
                                        Hi, It can be done if you can get the focal length close enough, and be able to adapt the original lens cell just right to keep the internal baffles from
                                        Message 19 of 20 , Jul 11 7:24 PM
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                                          Hi,
                                          It can be done if you can get the focal length close enough, and be
                                          able to adapt the original lens cell just right to keep the internal
                                          baffles from vignetting.

                                          Look into this:
                                          http://www.islandeyepiece.com/shopexd.asp?id=223

                                          Or, you might visit Surplus Shed, they come up with a few 80+mm short
                                          f.l. lenses. You can get creative balancing the OTA without too much
                                          hassle. lots of guys are making their own "copy scopes" this way.
                                          Good Luck, Dave Castillo
                                        • George Cushing
                                          ... short ... You d have to add 8.25 in length to use that 560 f/l Objective and 2 to use a 400mm f/l. I ve used a $30 63mm dia. 360mm f/l objective from the
                                          Message 20 of 20 , Jul 12 6:23 AM
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                                            --- In ETXASTRO@yahoogroups.com, "dobdave1" <david.castillo1@...>
                                            wrote:
                                            >
                                            > Hi,
                                            > It can be done if you can get the focal length close enough, and be
                                            > able to adapt the original lens cell just right to keep the internal
                                            > baffles from vignetting.
                                            >
                                            > Look into this:
                                            > http://www.islandeyepiece.com/shopexd.asp?id=223
                                            >
                                            > Or, you might visit Surplus Shed, they come up with a few 80+mm
                                            short
                                            > f.l. lenses. You can get creative balancing the OTA without too much
                                            > hassle. lots of guys are making their own "copy scopes" this way.
                                            > Good Luck, Dave Castillo
                                            >
                                            You'd have to add 8.25" in length to use that 560 f/l Objective and
                                            2" to use a 400mm f/l. I've used a $30 63mm dia. 360mm f/l objective
                                            from the shed to repair a ETX60 with a badly chipped objective. Their
                                            80mm/400 in a cell for $30 might be worth experimenting with.

                                            I've modified the old style ETX70 mount (similar to the ETX90 mount)
                                            to accept various short tube scopes. We bought 50 returned early 70s
                                            from Meade and sold off the optical tubes, the 20 or so 495 Autostars
                                            that came with them and the healthy mounts. I got to play with the
                                            broken ones. The conversions were sold to people who want to put a 90-
                                            105 Mak on a goto mount. They would accomodate a 4" Orion Mak.

                                            I've put some photos of the conversion in my album. One shows an
                                            80mm short tube refractor mounted, but as you can see the length is
                                            a bit or a problem.

                                            One photos also shows my fix for the common ETX broken dec axle. It
                                            also entails replacing the threaded stud in the hand wheel wheel with
                                            a 1/4-20 threaded insert.
                                            George
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