Quantum 4? and "Questar 7-ish"? OTAs on eBay
Davro Optical System M180-6FL-005 Surveillance Lens
Davro Optical System M180-6F7-007 DOS100-NDRZ-EC Surveillance Lens
7" maksutov optics by J.R. Cumberland
Quantum 4 OTAs?
may be worth rehabbing into astro telescopes if they can be bought at a low offer price
Bad eBay listing, actual items unknown
could be scratch, bashed, dropped a few times
I have no connection to these listings other than in my former days as a Davro Optical employee I may have built one or two of these.
Saw these on eBay, may be of interest. We built a lot of these surveillance and tracking/range/boresighting scopes. It is hard to tell what they are selling but here are the specs based on the model numbers:
DOS180-6FL (Specs for similar model on the Wayback Machine)
This is a 7" maksutov system similar to the Questar 7" (it uses the same J.R. Cumberland optics). This system is f/13.3 as opposed to f/13.4 for the Questar 7 Astro Mak (I could never tell if Cumberland was just shipping us Questar optics or if they made a slightly different "off the shelf" version for other customers). In the box (as best as I can remember) is a wheel with 5 focal reducer lenses and an empty hole, giving the six focal lengths. It also has counter-rotating neutral density wheels to control exposure. And it has electric motors to power the wheels and for power focus (moving the main mirror).
You can probably pull the OTA out of the system, add some kind of eyepiece mount on the back, add a finder and a knob on the exposed focus screw and you got a standard Mak (similar to the Questar 7 Astro Mak) ready for mounting.
You could also leave everything as is on the rails, put it on a (big) mount, and have an astrophoto scope with built in focal reducers and powered focus.
DOS100-NDRZ-EC (Specs on the Wayback Machine)
This uses Quantum 4 optics, a ND wheel system, and, i think, a lens set on a slider to change focal length. I am pretty sure the OTA can be unbolted and (with the same additions) can be used as a stand alone maksutov telescope (similar to a Quantum 100). Or it could be used as is.
The listings shows two different 7" units. They are also listing the DOS100-NDRZ-EC (4" mak). They have 4 of (something) for sale in the second listing (at half the price). Confusing? yeah.....
One problem in figuring out the specs on each unit is we built these units in small runs for each purchaser, so each order was custom, the buyer would want different features, so whats "in the box" may be a surprise.
Edited by telescope200, 03 January 2021 - 11:54 PM.