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Making a Meade 2080 LX5 operational, help?

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#1 jamestheviewer

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Posted 29 August 2021 - 07:34 PM

I recently purchased a 1988 Meade 2080 LX5 from craigslist.  My reasoning was, "Scopes are out of stock all over and I either have or can learn the skills to get it going again."  I got the tripod, wedge, 60mm finder (most of it), and the 2080.  Missing were the OTA star diagonal, eyepiece(s), any sort of power supply/adapter and cords, and the tube and eyepiece for the 60mm finder.  Also some hardware for the LX5.

 

I did, however, get some extras.  I got soil, a lot of it, all over the outside and some inside the finder and the OTA.  I got a small mud dauber's nest inside the finder.  I got a few desiccated insects inside the OTA.  I got a lot of moth wing sparklies inside the OTA, on the back of the corrector plate, generously covering the primary, and liberally sprinkled on the inside of the tube.  I got a lot of corrosion on the tripod legs.  Oh, and some cobwebs behind the mirror and inside of the baffle tube.

 

Pictures are (hopefully) attached, but not too many (yet).

 

Thanks to this site, I got the tripod leg corrosion cleaned up by a vigorous application of elbow grease and wadded up aluminum foil.

 

When I was inspecting the corrector plate, before cleaning it, I noticed that the secondary mirror assembly would spin freely inside its hole in the corrector plate.  When I removed the corrector plate (noting orientation) one of its retaining screws was stripped.  I unscrewed the secondary mounting assembly and set it aside.  Using a 70% water, 30% isopropyl alcohol, 2 drops of dish soap mix I loosened most of the dirt from the corrector plate, rinsed, then let it soak for a few minutes in warm water, and set it aside to dry.  After drying I made another indexing mark on the corrector and OTA.  An irregular cloudiness that I'd noted before cleaning I determined to be the corrector plate coatings separating from the glass.

 

Questions Set 1:

1.  Is the orientation of the secondary mirror assembly in the corrector plate important?

2.  What, if anything, should I do about the coatings on the corrector plate?

3.  Pics below, but secondary mirroring is 'spotting' and coming off of the secondary.  Should I get it recoated? (pics below)

 

Using a lint-free cloth I dampened and scrubbed a bit on the inside of the OTA and finder to remove mud streaks.  That cleaned up okay.  I used various optical-type squeeze bulbs to blow the cobwebs out of the baffle and from behind the mirror.

 

Pre-cleaning inspection of the primary revealed 1, half-inch-ish scratch in the mirror near and tangent to the baffle.  I cleaned the secondary using the same 70/30 mix as above and lots and lots of cotton wool, kleenex, and cotton pads.  There were some oily deposits and some greasy deposits that have left a faint haze on the primary.

 

I put it all back together and took it out to collimate.  I managed to get Jupiter with a low-power eyepiece and managed to get the de-focused donut roughly symmetrical from its start as tightly pinched on one side and wide on the other.  However, when starting to collimate 1 of the three screws was fully tight and the other 2 pretty loose.

 

Today I tried focusing the scope with a 2-inch Celestron dielectric star diagonal and 25mm and 7mm eyepieces at the top of a wooden power pole about 1/2 mile away.  The best focus I could get could be generously described as "soft" and ungenerously described as "poor."

 

Question Set 2:

4.  How tight should the collimation screws be?  Loose?  All firmly tight?

5.  How best to remove the "haze" left behind on the primary (haze pics below)?

6.  Is 1/2 mile away sufficient to get a good, sharp focus with this scope and a 25mm eyepiece?

7.  Is the current Meade Power Adapter, 12v 5A sufficient to run this scope?

8.  Knowing that this is a Halley-era scope, should I stop with the spending already and be happy?

 

And, finally, if anybody spots anything that I should have asked but didn't, what is it?

 

P.S.  I do plan to replace the capacitors in the LX5 and hand controller.

 

Pics below.  The first is the before.  The 2nd is the primary mirror haze.  The 3rd is more primary mirror haze and you can see the spot on the secondary where the mirroring is gone.

 

M2080.jpg

Attached Thumbnails

  • primary_haze.jpg
  • primary_haze2.jpg


#2 Rick-T137

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Posted 30 August 2021 - 06:53 AM

WOW! You have your work cut out for you, and it seems like you're doing a great job so far! Good on you for rescuing this now classic telescope. I'll see if I can answer some of your questions...
 

Questions Set 1:
1.  Is the orientation of the secondary mirror assembly in the corrector plate important?
YES - the secondary mirror should be returned to its original position if possible. However, the scope should work fine with the secondary in any position, but there likely will be one orientation that is sharper than the others. If your secondary was spinning freely, then you likely won't have the original orientation. Trial and error is really the only method to get that orientation back.

2.  What, if anything, should I do about the coatings on the corrector plate?
I wouldn't worry about them too much. I have an old LX3 OTA that has failing corrector plate coatings and it still works fine.

3.  Pics below, but secondary mirroring is 'spotting' and coming off of the secondary.  Should I get it recoated? (pics below)
YES - you can get it recoated. I had the same problem with my LX3 and I sent it off to Fullum Optiques in Quebec Canada and for $120 (CAD) they recoated my secondary and it works wonderfully.
 
BEFORE RECOATING:
Meade 2080 Secondary

 
AFTER RECOATING:
Meade 2080 Secondary FIXED

 
Question Set 2:
4.  How tight should the collimation screws be?  Loose?  All firmly tight?
They should be snug - not loose for sure, but not firmly tight. And they should all be the same snugness - one screw shouldn't be a lot tighter than the others.

5.  How best to remove the "haze" left behind on the primary (haze pics below)?
Unfortunately I don't have any advice on that - I do my best to never touch my mirrors. Hopefully others will have some good advice on how to get rid of the haze...

6.  Is 1/2 mile away sufficient to get a good, sharp focus with this scope and a 25mm eyepiece?
YES - I believe 25 ft is the minimum focus distance for a 2080, so 1/2 mile should be plenty. Note, this would be good for attaining collimation, but not necessarily good for evaluating the optics. I do something similar with my scopes - I have an artificial star that I use to get decent collimation, and I do the final tweaks in the field using Polaris.

7.  Is the current Meade Power Adapter, 12v 5A sufficient to run this scope?
YES - it should be fine. When operating my LX6 in my backyard, I use a 12v 5A wall plug and in the field I use a Celestron Power Tank and plug the scope directly into one of the "cigarette lighter" style sockets.

8.  Knowing that this is a Halley-era scope, should I stop with the spending already and be happy?
That's an interesting point. Your soft images may be the result of the secondary having spun out of orientation. You could try and see if there's a more favourable orientation that gives you sharper images. I did not regret spending the extra money on getting my secondary recoated, but I have left my corrector alone so far. 
 
And, finally, if anybody spots anything that I should have asked but didn't, what is it?
I don't think so. I think you've done a fantastic job restoring the scope to working order. You may be right that it'll only get "so good". Good luck!


Clear skies!

Rick


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#3 jamestheviewer

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Posted 30 August 2021 - 09:13 AM

Thanks for the reply and encourgement!  Mine is not the 'silver coated optics', according to inspection and the tag on the front. :)

 

There are signs that it has been opened before, like gouges through the tube interior paint in a couple of places.  It came with the SCT ring and first tube (up to the star diagonal) of a star diagonal, but was otherwise open at the back.  The gouges aren't like mouse scratches, but more like tool slippage.  If I had to guess, that is, and that's what I'm doing.

 

I was trying to avoid de-forking it to try to preserve the setting circles' positions on the fork arms, but they don't agree and aren't off in any useful fashion.  They seem to be zeroed at random and different.  Which has brought me to the realization that I'm not preserving anything besides my time by not de-forking.  Also, apparently taking it apart a lot more than I have so far is required for desoldering and replacing capacitors.  I'm trying to find some pictures online of the fork arm setting circles, but that's a rough slog.

 

I put a wee bit more elbow grease into the primary between when I posted yesterday and observing last night and with an 8mm eyepiece I could see the gap between Saturn and its rings, and pretty clearly see Cassini's Division.  Jupiter and the Galilean moons were easily visible, with clearly seen cloud bands on Jupiter.  The limb of both planets, however, was a bit ... fuzzy?  Not sharply delineated, anyway.

 

My next plan is to defork, remove the mirror cell, and clean the primary more thoroughly.  While that's off I was thinking trying to darken the tube's interior paint.  I've been reading paint threads here to that end.

 

If anyone reading could take a pic of the setting circles on the fork arms and posting a clear pic of that, or tell me where to go to learn how to set those, I'd be very grateful.


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#4 Rick-T137

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Posted 30 August 2021 - 10:04 AM

Sounds like the optics are "coming into focus" nicely! smile.gif

 

De-forking is certainly an option - that's what I did with my LX3. It rides on a Sky-Watcher EQ-5 right now and my youngest uses it.

 

The limb of the planets not being sharp - I think I recall just reading about that phenomenon recently and it may not be your optics, but an actual "thing"... 

 

Finally, re: setting circles - I've had to re-align mine many times on my LX6. I just wish I could remember off the top of my head what I did. I know my work bench in my shop is completely level, and I put the base of the scope on the bench so it is upright, and then I use a level to point the OTA perfectly downwards. Then I set the setting circle - I just can't remember if I set it to +90 degrees or -90 degrees... hang on a sec...

 

I think it's actually 0. In theory, when the scope is pointed at Polaris, it should read +90 on the declination circles. I'll double check tonight when I'm messing with my scope.

 

But according to the manual, the only way for certain is to centre your scope on a target of known RA and Dec and then adjust the Dec appropriately with the object centred.

 

Clear skies!

 

Rick


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#5 jamestheviewer

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Posted 30 August 2021 - 11:01 AM

Ah, thanks for the information.  I was using de-fork to mean take apart, prior to re-assembly.  I just learned that you're using it as describing a permanent thing, prior to mounting on a different mount.

 

I like my LX5 as-is, with improvements.  I used to read astronomy magazines voraciously and wanted one ever since they came out.

 

Eventually (this is pie-in-the-sky stuff) I'd like to put encoders on and make it a push-to.  I need to get the 60mm finder sorted.  I might need a new star diagonal for it, the current one is cracked between the two threaded holes.  It is missing the tube and eyepiece and two of the long plastic alignment screws.

 

One thing at a time! :D


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#6 Rick-T137

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Posted 30 August 2021 - 02:42 PM

AH! Yes, I fully encourage you to use the LX5 mount if that's what entices you. I used to have my LX6 Premier OTA on the EQ-5 mount, but I have found I much prefer the original fork mount - it's just so much more comfortable to use. Plus I like it's old school vibe. 

 

I used to have a 2120 LX6 Premier that had the encoders and was push to - it was pretty cool! But I have embraced  more simplicity in my observing, so with my 2080's LX6 Premier mount, I don't have the encoders and most nights I don't even use the hand controller. Just the RA motor and that's it. I've been keeping my eye out for an LX10 mount, as it will run off a 9V battery (just like my first C8 did!). Talk about simplicity!

 

Clear skies!

 

Rick


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#7 jgraham

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Posted 30 August 2021 - 08:41 PM

+1

 

I deforked my 2120 LX6 Premier and used it on an Atlas for a while, but ended up reforking it. It is very comfortable to use and makes a fine star-hopper.


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#8 jamestheviewer

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Posted 30 August 2021 - 09:04 PM

I found the website for Photonic Cleaning, a lens and mirror cleaning polymer that you brush on, let dry, and then peel off.  The pics on their testimonials page look quite good (no surprise there), but one of them describes a guy's cleaning that left that same purplish haze I've got, and the after pic looks clear.

 

Quite interesting, at $665 for enough to clean a 1-meter mirror.


Edited by jamestheviewer, 30 August 2021 - 09:30 PM.


#9 jgraham

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Posted 03 September 2021 - 08:40 AM

I have refurbed several old SCTs with optics in various conditions. The roughest had mud-dobber nests all over the mirrors, but with care is cleaned up fine and is now an excellent performer with just a tiny bit of coring loss off of the secondary. For something like a corrector which is fairly easy to remove and isolate from structure I prefer to take is completely apart (being careful to mark orientations) hand hold it under running water, first letting the soil soak and soften, and then slowly work if off with my bare fingers. This usually does a nice job of removing most of the soil, leaving behind a film of fine particles. These I was off with a surfactant such as a mild soap or a good window cleaner, rinsed under flowing water, rinsed with distilled water, and dabbed dry with a lint-free tissue. Final touch-up with foggy breath, lint free tissue, and a puffer bulb. It's fun to water these old optical surfaces emerge in their original pristine condition. On the rare occasion where the coating have a bit of fog they usually still work okay, though you may get a bit of haze around bright objects.

 

Food for thought...


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#10 jamestheviewer

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Posted 06 September 2021 - 12:38 PM

I've made a bit of progress.

 

The dec pressure clamp lever seems to be too loose when engaged to the limit.  The tube will still move with light pressure.  Light is not nearly enough to knock the scope and lx5 over when sitting on the floor.  But it will hold the tube for viewing practice.  

 

The RA clamp seems to be far too tight, however.  It takes almost enough force to clamp to the limit as it would take to knock the tube and lx5 over when sitting on the floor.  The tube and base have to be held when clamping this to the limit because it will scoot around on the floor otherwise.

 

I have the objective, tube, and star diagonal for the Meade RA finder.  I pieced something together with various pieces and it is a few millimeters too long to allow focus.  I substituted the Celestron RA finder that I had and with 4 sheets of paper slipped under the front of the shoe I have enough travel in the mount rings to align it.

 

I don't have a power supply yet, that should arrive tomorrow.  12v 5A, rated for this scope (and a lot of others besides).

 

Real Life has hit a bit, as well as finances and holiday shipping.


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#11 jamestheviewer

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Posted 07 September 2021 - 08:57 AM

The dec setting circle clamp (the round knob) had been tightened down so far that it took careful application of channel locks, with the teeth wrapped in a washcloth, to loosen them.

 

I took it out last night for a quick viewing/testing session.  With the Celestron RA finder roughly adjusted during the day I was able to find Polaris in my Bortle 8/9 skies.  Adjusted the setting circles (for fun and old times sake).  With a finder Jupiter and Saturn were much easier to find.

 

I'm still not satisfied with the optics.  At higher magnifications things seem a bit cloudy.  Not as badly as the old vaseline on the lens technique in movies, but more like looking through a lightly breath-fogged window.  Even after allowing things to settle stars do not quite resolve to points.

 

A power supply for this scope should arrive today.  That'll let me haul out the multimeter and start checking over the electronics.  8x slew and a clock drive sure would be nice.

 

So far most of this work has been for evaluation.  My question was, "Is this scope good enough to warrant further expense?"  I'm still not sure of the answer, but I'm feeling better about proceeding.

 

Next up, powering up the unit to see if it powers on and if the motors work.  I've read that if the capacitors are blown this won't hurt the power panel and base electronics.  I'll leave the handset unconnected until I get the capacitor(s) in that replaced because I've also read there's a capacitor in there that, if it blows, ruins the hand controller.

 

My rough plan is to test the base, then pull the tube, disassemble the base, re-grease everything in there, replace the caps everywhere, and with the tube off at that point take the rear cell / primary mirror assembly off and give the primary a thorough, careful, cleaning.

 

When I put it all back together I plan to leave the secondary holder a bit loose so that I can try rotating that to find the position with the sharpest focus.


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#12 jamestheviewer

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Posted 07 September 2021 - 01:12 PM

Power supply arrived.

 

Without the hand controller plugged in, hooked up to electricity and the red LED showed when I powered it on.  Nothing else happened.  The ammeter needle didn't even seem to wiggle, stayed right at 0.  Then I had to go back to work.


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#13 Rick-T137

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Posted 07 September 2021 - 02:56 PM

Power supply arrived.

 

Without the hand controller plugged in, hooked up to electricity and the red LED showed when I powered it on.  Nothing else happened.  The ammeter needle didn't even seem to wiggle, stayed right at 0.  Then I had to go back to work.

Hmmmm... that could be an issue. When I power up my LX6, I believe the ammeter goes to about .8 or .9 amps and it sits there. That is with the controller not plugged in. I believe it draws more with the controller, and then more again when I am slewing. 

 

The red light indicates the unit is on - so that's a good thing. When you have it turned on, can you hear any noises from the drive base? You could try using a screwdriver with the blade on a metal part of the base and then place your ear against the plastic handle of the screwdriver. See if you notice a difference in sound between off and on. I know my base is super-quiet, but I sometimes hear it "gurgling" in the middle of the night while I'm observing.

 

Clear skies!

Rick



#14 jamestheviewer

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Posted 07 September 2021 - 06:00 PM

Even under a magnifying glass the ammeter shows no movement.  Trying for sound or vibration through bone conduction doesn't show anything, either.

 

It is officially dead.  Now to get into its guts and resurrect it!

 

Dramatic, eh?  But that's the only option left.  I opened up the main panel (4 screws) and that is the typical, old-school, rats nest of wiring down in there.  I'm not quite half tempted to get some protoboard and at least move the components into something manageable and mountable.  But if I can get it to work without resorting to that I'll try it.

 

Next step is to get it all torn apart 1) replace capacitors, then 2) see if the ra motor 3) is getting voltage and 4) moves when separated from everything else.  Also, 4) see if I can spin it up initially and then determine whether it'll keep going under its own power or not.  While I'm in there I guess I'll also look for shorting wires in that panel and check for hot components.

 

Yay.


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#15 Rick-T137

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Posted 07 September 2021 - 06:38 PM

I don't know if you're already on the list, but there's an excellent Meade LX5 LX6 email list at:

 

https://groups.io/g/meade-lx5-lx6

 

And someone on there might have the technical chops to advise you on the journey you're about to go on.

 

Clear skies!

 

Rick


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#16 jamestheviewer

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Posted 07 September 2021 - 11:30 PM

Thanks for the group link.  Is it very active?  The messages timeline doesn't show too many messages lately.  If I'm reading  it correctly.

 

The other other option is to gut it and put in something OnStep based, or similar.  Then I'd really have something!  A goto-capable scope with fuzzy optics! :D

 

I need to do some thinking about how to approach this.


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#17 Rick-T137

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Posted 08 September 2021 - 06:48 AM

It hasn't been active lately, but I have seen technical questions answered on that list recently. So I know someone out there is listening. smile.gif


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#18 jamestheviewer

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Posted 09 September 2021 - 12:03 PM

I'm still using the scope while I read up and think about my options.  So far, except for polar alignment, I've been observing the Southern sky or using orientations that are the same as my collimation orientation.

 

Last night, after polar aligning the scope we were observing primarily Jupiter and Saturn.  A few views of star fields, those fireflies of the sky.

 

I then turned the scope "upside down" relative to collimation orientation and tried to find Mizar.  The fireflies of the sky splatted on the windshield of my eyepiece.  Seriously, that's what the stars looked like after a mirror flip (and flop).  I checked collimation by defocusing on the nearest bright star and the central hole was off-center.  Not as far off as it had been when I first got the scope, but it was visibly off-center.

 

Stars simply would not resolve to points.  The best that I could get them looked like bug-splatter, narrow at one end and fanning out more the farther away from the narrow end.

 

1) Is this much collimation change and de-focus normal for this type of scope? 

2) I'm wondering if this could be related to how tight and loose the secondary screws were when I received the scope.  Could I just not have the secondary collimating screws tight enough to hold the secondary firmly enough when I flip the orientation?

 

I realize that I could have multiple problems going on here.  What I mentioned above, also the primary might not be securely fastened to its carrier, slop along the primary to central baffle tube, and other things besides.

 

3) Am I missing anything?


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#19 Rick-T137

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Posted 09 September 2021 - 12:28 PM

I'm still using the scope while I read up and think about my options.  So far, except for polar alignment, I've been observing the Southern sky or using orientations that are the same as my collimation orientation.

 

Last night, after polar aligning the scope we were observing primarily Jupiter and Saturn.  A few views of star fields, those fireflies of the sky.

 

I then turned the scope "upside down" relative to collimation orientation and tried to find Mizar.  The fireflies of the sky splatted on the windshield of my eyepiece.  Seriously, that's what the stars looked like after a mirror flip (and flop).  I checked collimation by defocusing on the nearest bright star and the central hole was off-center.  Not as far off as it had been when I first got the scope, but it was visibly off-center.

 

Stars simply would not resolve to points.  The best that I could get them looked like bug-splatter, narrow at one end and fanning out more the farther away from the narrow end.

 

1) Is this much collimation change and de-focus normal for this type of scope? 

2) I'm wondering if this could be related to how tight and loose the secondary screws were when I received the scope.  Could I just not have the secondary collimating screws tight enough to hold the secondary firmly enough when I flip the orientation?

 

I realize that I could have multiple problems going on here.  What I mentioned above, also the primary might not be securely fastened to its carrier, slop along the primary to central baffle tube, and other things besides.

 

3) Am I missing anything?

Wild stuff! 

 

1) No, that is likely not normal. With my SCT, I don't experience any noticeable mirror flop when crossing the meridian (ie: moving from southern sky to northern sky) and only minimal image shift when focusing.

2) The secondary screws should be snug but not really tight - the secondary certainly shouldn't be moving around at all when using the scope.

3) I am wondering if your primary mirror is loose, or if the baffle grease on your primary baffle is completely gone. One thing you can try is turn the focus knob continually one way until you hit the "stop" (the mirror stops moving), then continually turn it the other way until you reach the other "stop". Repeat this 2-3 times. This moves the primary mirror up and back the length of its travel and may re-distribute the baffle grease more evenly along the baffle tube and may reduce the mirror flop. Alternatively, you could take your scope apart and see if the primary is loose on the baffle carrier. If it is, then simply tightening down the nut will help a lot (NOTE: I have never done this part before, so I'm not 100% sure of the steps to accomplish this adjustment - maybe see if others with more experience chime in).

 

Something certainly doesn't sound right. With my 2080 I can look at Jupiter and Saturn in the southern sky and verify that my scope is properly collimated, and then slew over to Mizar in the northern sky and my collimation is still good. 

 

I hope that helps!

 

Rick


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#20 jamestheviewer

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Posted 09 September 2021 - 12:32 PM

Thanks very much for the reply!  That helps tremendously.  I didn't remember them acting like this back in the 80s/90s, but you know how memory gets.

 

Yet another reason to really tear this thing apart.  :D


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#21 jamestheviewer

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Posted 09 September 2021 - 12:37 PM

Informative baffle tube grease post:  https://www.cloudyni.../#entry10027547


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#22 Rick-T137

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Posted 09 September 2021 - 12:42 PM

Informative baffle tube grease post:  https://www.cloudyni.../#entry10027547

For sure, Pete knows his stuff. I have some of his equipment on my scope!


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#23 jgraham

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Posted 11 September 2021 - 12:09 PM

+1

 

A common issue that I have encountered with older SCTs is loose mirror lock rings and dried out/wrong grease on the baffle slide. Snugging the lock ring is an easy fix and I often clean the baffle slide to remove the old grease and replace it with a thin film of Mobil 1 synthetic.

 

Food for thought.


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#24 jamestheviewer

jamestheviewer

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Posted 11 September 2021 - 03:20 PM

Thanks for that information, jgraham.  I appreciate it.  I've been wondering what sort of oil / grease I should use to lubricate it, so your comment is very helpful.

 

Earlier today I got the scope and base up on a table.  I checked the tightness of the collimation screws and sure enough, the three were at different levels of 'snug' with one being more 'hold on by a thread or two.'  I tightened them and am now waiting for dark (and no clouds) so I can collimate it and then do a meridian flip to test it.


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#25 jamestheviewer

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Posted 11 September 2021 - 11:17 PM

Took it out tonight with the newly-tightened secondary, collimated on Polaris, then turned it upside down to simulate a meridian flip and pointed it at Jupiter.  Inverted the view was just as good as right-side-up.  Flipped it back right-side up and the view was the same.  I'm calling it, this problem happened to be the easiest possible problem, loose secondary, and tightening it fixed it.

 

Now, the views are still a bit soft.  That said, we got the north and south hemisphere main, tan, cloud bands and infrequently we could see a bit more detail along the equatorial area, especially using 12mm or so eyepiece settings (8mm - 24mm Celestron eyepiece).

 

I've ordered some nitrile gloves for handling optics and some Mobil 1 synthetic grease for the baffle.  That should be in next week.  Until then I believe that I'm just going to play around with this a bit and let it sit otherwise.

 

Thanks for all of the help, information, and suggestions. They've helped immensely and I am very grateful. :)


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