Maksutov Telescope Making

[SthBohemia]

Over the last few days I resurrected articles, pamphlets etc that I purchased 55 odd years ago with the idea of constructing a Maksutov. Went so far as to almost purchase a 7" BK-7 concave/convex blank from Edmunds USA.

No wonder they have not been re read for 55 years, it must have taken me a month to get over the shock. Detailed procedures outlined by Warren Fillmore, Allen Mackintosh, Horace Dall and John Gregory have once again convinced me a Mak is well beyond my capacities. Newtonians are a piece of cake, a Dall Kirk reasonably easy, true Cassegrain a pain in the rear but nonetheless, with blood, sweat and tears achievable.

The 3 optical surfaces of a Mak are NOT all spherical, this in particular applies to the meniscus lens. Testing these surfaces requires an optical flat the same diameter as the primary mirror. A large optical flat is a nightmare to figure even to 1/8th wave...

Making all 3 optical surfaces MATCHIING aspheric, falls into the labour of love category!

Proper collimation also requires the same optical flat.

Add to which the lens should be housed with an adjustable cell to allow proper 'tilt' to collimate the 2 optical surfaces. I might add the lens of all the SCT's SHOULD be housed within an adjustable cell as well.

If the Questar company does actually follow the 'true Dimitri Maksutov' design it is of no wonder they are a little expensive.....

As for the other companies that claim to make Maks 😞 :east said the better!!

[Peter Drew]

Along with a colleague James Muirden I made many Maksutovs from 90mm to 300mm aperture during my 35 years as a professional telescope maker before my retirement in 2006.  Jim made the optics and I made the mechanics.  We introduced the first UK commercially made Maksutovs to the market.  I am not an optician but I am very familiar with the process to make Maksutov optics, attention to detail is the most important aspect.     🙂

[Paul M]

57 minutes ago, Peter Drew said:

Along with a colleague James Muirden I made many Maksutovs from 90mm to 300mm aperture during my 35 years as a professional telescope maker

300mm Mak! Sounds interesting

I wonder if you know if any of your Maks are still in service? 

 

[Peter Drew]

I made only 4 of the 300mm versions, 3 in private hands and one for the Oxford University astrosoc.     🙂

[RT65CB-SWL]

Not quite in the same league as the original post, but following a damaged rear end to my Meade ETX105, I found a local engineering workshop near me
and asked them if they could make a replacement backplate for it. I just gave them them the original ETX backend and a hand-drawn plan to work with.

The following images is the result...

The SCT adaptor and 1.25" visual back are by Baader Planterium...
.

 

Since 2021 https://wegatoptical.com/shop/ make replacement backplates for the ETX105.
They also make the backplates for the ETX90 & ETX125.

Edited September 4, 2022 by Philip R

[SthBohemia]

5 hours ago, Peter Drew said:

Along with a colleague James Muirden I made many Maksutovs

Under what brand did you market them? I would like to keep an eye out for one of them 🙂 

[Peter Drew]

They were branded BAS  (Bedford Astronomical Supplies).     🙂