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
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.
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 firstname.lastname@example.org, phone is 215-862-5277
Edited by Optics Patent, 28 March 2017 - 01:31 PM.