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Questar Maintenance, Repair, and Restoration - Reference and Resource Thread

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#1 Optics Patent

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Posted 28 March 2017 - 01:29 PM

For those interested in the maintenance and repair of Questar scopes, here are some useful links and info I have catalogued.  Please add any other tips, links to threads or other information below. 


Major disassembly and reassembly
  

Control box disassembly, removal and replacement of mirror and corrector (photo album) 

Tip: the Barlow control knob is set-screwed to an aluminum boss that is set-screwed to a threaded shaft.  After loosening the set screw, the boss will unscrew - it won't pull off. 

 

Removing the retaining ring and corrector lens

 

Removing the retaining ring and corrector lens

 

Mirror removal

 

Base and drive disassembly

 

Disassembly of declination drive, removal and polishing of arms.

 

Minor repairs

 

How to adjust or remove and replace the finder mirror
 

Adjusting tube rotation
 

Refinishing a Q7
 

How to touch up scratched black anodizing
 

Questar wrench sizes.  OTA mounting screws and those mounting the control box are #3-56 SS cap head screws 1/4".  Bristol wrench size .096 diameter, 6 flute.  Bristol screws are generally unavailable, including from Questar.  See this post on the issues regarding Bristol vs. Allen in a Questar.

 

Helpful tools and supplies

  • Pec-Pad lint free wipes.  Cheap at 10 cents each. 
  • Dust blower. Giottos AA1900 Rocket Air Blaster Large - Black
  • 4x reader glasses (cheap on Ebay) or Optivisor, dental binoculars, etc. for close work
  • LED flashlight, with some kind of mount to hold it
  • Grain Alcohol (Everclear®).  An effective cleaner that is safe and odorless, and a gentle first solvent if water isn’t enough to clean.  Suitable for optics with delicate coatings, but will dissolve some black baffle paint.
  • Also for cleaning optics (much more expensive and no better but a handy dropper bottle) is the undrinkable methanol-based Photographic Solutions Eclipse Cleaning System Solution
  • Automobile paste wax for protecting polished aluminum and anodized OTA moon map and dew shield surfaces.
  • Gunsmithing screwdrivers that are hollow ground (parallel at tip, not wedge) to avoid damaging screw slots.
  • 2mm Bondhus (ball-end) Allen wrench.  For newer scopes having Allen instead of Bristol Screws.  Replace your finder mirror bracket Bristol screws with these to enable the bracket to be removed and replaced without ponderous reseating of the Bristol tool each 1/6th turn.  Conserve the removed irreplaceable Bristol for restoring older scopes with missing or damaged screws.
  • Lens spanner wrench for removing retaining rings (must be up to 100mm size).  $10-20 on Ebay.
  • Questar email for parts orders is questar@erols.com, phone is 215-862-5277

Edited by Optics Patent, 28 March 2017 - 01:31 PM.

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#2 Optics Patent

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Posted 10 April 2017 - 11:00 AM

Note that the threads on the tiny screws that secure the R/A indicator window to the turntable (fork base) are #0-80.  The window is tapped for these threads.


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#3 Optics Patent

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Posted 18 April 2017 - 03:11 PM

How to align the corrector lens.


Edited by Optics Patent, 18 April 2017 - 03:12 PM.

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#4 DAVIDG

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Posted 19 April 2017 - 10:34 AM

 If you look carefully along the edge of the corrector you will see an aligned line etched in the edge.  This mark should be at the 6:00 o'clock  position when the eyepiece is rotated to be at the 12:00 o'clock position. You loosen the retainer ring, and I use a piece of tape placed near the edge of the corrector to grab it and rotate into position. Be sure it doesn't move when you retighten the ring. 

 

               - Dave 



#5 Optics Patent

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Posted 23 April 2017 - 08:35 AM

Where to get a finder mirror recoated.



#6 elwaine

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Posted 28 April 2017 - 07:44 AM

Great thread. Could we get this one pinned?


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#7 Optics Patent

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Posted 07 May 2017 - 06:01 PM

How to Repair Vinyl Questar Cases.


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#8 Optics Patent

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Posted 16 May 2017 - 02:16 PM

Axial port diameter changes through history



#9 Optics Patent

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Posted 23 May 2017 - 02:20 PM

How to remove or loosen a stuck eyepiece holder ("Diopter Adapter")



#10 Optics Patent

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Posted 31 May 2017 - 03:10 PM

How to Test the Slow Motion Drive Operation on a Questar Telescope.


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#11 Optics Patent

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Posted 12 June 2017 - 06:33 AM

Polishing the dew shield.

 

I acquired a scope that had been stored in a fitted foam case that had badly degraded.  The foam reacted with the control box paint to pit and blister it, and had left marks on some aluminum surfaces.  After cleaning the dew shield (plain, no start chart) it still showed a pattern on the surface from the effects.

 

Carefully, I tried my usual jewelry polish on a small spot, not using new polish but just an old spot on the rag, plus a little spit.  Happily, it removed the hazy pattern entirely and provided a wonderful gloss.  I wouldn't have dared try this on one with a printed moon map or star chart, or even on any good dew shield just the brighten up the gloss.  But if you have etched fingerprints or slight rub marks this might be a good treatment.



#12 Joe Eiers

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Posted 14 June 2017 - 02:04 AM

You and your "jewelry polish!"  bow.gif

 This illusive magic material you use seems to fix everything!  It's kind of pointless to share such helpful hints without any place to buy the stuff, yes?

 My poor baby needs help...

 Too bad I can't find any... :(

  Joe



#13 Optics Patent

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Posted 19 June 2017 - 01:33 PM

After reading in an old manual (1966?) that Zinc Stearate was used as a dry lubricant for the push-in legs, I had to try it.  ~$5 supply from Ebay, and...

No apparent benefit.  Don't bother.



#14 Les Aperture

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Posted 19 June 2017 - 06:07 PM

Corn Starch.



#15 Optics Patent

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Posted 20 June 2017 - 11:20 AM

You and your "jewelry polish!"  bow.gif

Source found.  Anyone interested in a bottle or two please message me or Joe - it's a shipment from England - min 6 bottles at about $12 each.  Plus shipping from the US recipient to the end user.



#16 Optics Patent

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Posted 18 July 2017 - 12:59 PM

Questar extension tube thread specifications.

 

As noted above, the extension tube threads are M42 x 1.0mm (M42 refers to metric 42mm diameter). 

 

M30 x .75mm is used for:

  • Early Konig & Erfle external threads
  • Brandon internal thread for filter, Barlow
  • Modern Axial port and swivel coupling
  • Adapter ring internal thread for capture between extension tubes

Modern Brandon eyepiece external threads are M32 x 0.80

 

Control Box aperture for eyepiece holder (historic and modern unchanged) 0.95" x 0.75mm, same for original axial port pre-1964.

 

Axial port diameter from ~1964-~1972 was about 0.010" smaller than the modern size as discussed here.

 

Then there are the two types of threaded eyecups.  One is very common, and one with a different thread pitch is "rare" and was offered for only a brief time. If you order, Questar will assume it's the usual one.


Edited by Optics Patent, 18 July 2017 - 02:31 PM.


#17 Optics Patent

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Posted 18 August 2017 - 04:09 PM

Removing the barrel from the base in a 1957 Questar.



#18 starman876

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Posted 23 August 2017 - 01:55 PM

So, how does one align the primary?  The only thing I see that possibly could have any effect would be the star washer underneath the mirror. Do they bend the teeth to align the primary with the secondary?



#19 Optics Patent

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Posted 23 August 2017 - 02:42 PM

I thought the whole design was that the primary never needed aligning?



#20 starman876

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Posted 23 August 2017 - 06:10 PM

I thought the whole design was that the primary never needed aligning?

One would think that was the case, but I have one that is out of alignment.  When I take it apart I will figure out why, but meanwhile I was hoping someone would know if the scope is out of alignment how does one put it back into alignment.



#21 starman876

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Posted 23 August 2017 - 07:41 PM

if you look at that satr type washer underneath the primary one would think that of the teeth on that washer were not evenly set the mirror would be at an angle. well, that is it it is a washer and not a spring type metal to just keep presure on the mirror.  However, one would think that any presure on the mirror might distort it.


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#22 Optics Patent

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Posted 23 August 2017 - 08:58 PM

I suspect that the mirror's alignment is established by the flange forward of the mirror, and the star spring washer simply ensures that the mirror is pressed against it.



#23 starman876

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Posted 23 August 2017 - 09:24 PM

you are most likely correct.   However, the question is still when a questar goes out of collimation what does one have to do to put it back into collimation?



#24 starman876

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Posted 23 August 2017 - 09:44 PM

I suspect the primary is loose.  When I hold the front of the scope down towards the ground and give it a few gentle taps the scope goes back into collimation.  


Edited by starman876, 24 August 2017 - 06:56 AM.


#25 DAVIDG

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Posted 25 August 2017 - 09:34 AM

 There is an alignment line on the back of the mirror. It either goes at the 12:00 or 6:00 o'clock position to the eyepiece. I'm sorry I can't remember which .  I know the corrector has an alignment mark that goes at 6:00 o'clock. What happen is that the mirror, like the corrector can slowly rotate out of position over the many years these scope have been around. 

 

          - Dave 




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