Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Mak-cass ?

This topic has been archived. This means that you cannot reply to this topic.
8 replies to this topic

#1 ardwlf

ardwlf

    Lift Off

  • -----
  • topic starter
  • Posts: 1
  • Joined: 18 Jun 2007

Posted 18 June 2007 - 10:58 PM

Hi I'm a newbe. I just bought an 8" Mak-cass from ebay, the guy I bought it from seems to think its some sort of prototype. The funny thing about this scope is that both Primary, and secondary mirrors are coated on the back side. The Primary mirror is concave on the face side and convex on the back side.The corrector plate is concave on the mirror side and flat the other side. Does anyone know what type of scope this is?

#2 trainsktg

trainsktg

    Aurora

  • *****
  • Posts: 4983
  • Joined: 23 Aug 2005

Posted 18 June 2007 - 11:29 PM

Well, a pic would certainly help. The coatings being on the back side or the primary doesn't make sense to me. Also, a Maksutov has a meniscus, not a corrector. What you are describing sounds much different than a regular Mak. Is the primary perforated, or it there a tertiary mirror as well?

Pleasepost a few pics, I'm intrigued.

And welcome, too, to our little bunch here on CN.

Keith

#3 trainsktg

trainsktg

    Aurora

  • *****
  • Posts: 4983
  • Joined: 23 Aug 2005

Posted 18 June 2007 - 11:37 PM

I just reread your post. I think you may have your definitions of primary and secondary reversed. If I'm correct in my guess, the clear glass at the front of the scope with a convex/concave matching curve with a small mirrored spot in the center is actually the meniscus and secondary mirror. The mirror at the back with concave mirrored face and flat back is the primary, which is much larger in size than the secondary spot at the front. IF my guess is correct, you do indeed have a Mak-Cass, but identification of brand is only possible with some good pics.

I hope I helped somewhat.

Keith

#4 refractory

refractory

    Apollo

  • *****
  • Posts: 1338
  • Joined: 05 Feb 2005

Posted 19 June 2007 - 03:51 PM

I was considering bidding on this scope myself- congrats (assuming it works)! I wonder whether this has Mangin mirrors (not just mirrored on the back but the glass is deliberately designed to act as a lens). If images aren't radically distorted then you may have a very interesting project scope!

Jess Tauber

#5 trainsktg

trainsktg

    Aurora

  • *****
  • Posts: 4983
  • Joined: 23 Aug 2005

Posted 19 June 2007 - 08:44 PM

OK, I guess I missed this one. Is there a link available to see?

Keith

#6 luckyman

luckyman

    Sputnik

  • -----
  • Posts: 28
  • Joined: 01 Feb 2004

Posted 20 June 2007 - 09:03 PM

Item number: 270127731292 This might be it hope this helps

#7 trainsktg

trainsktg

    Aurora

  • *****
  • Posts: 4983
  • Joined: 23 Aug 2005

Posted 20 June 2007 - 09:21 PM

Yeah, its a Schmidt, not a Mak. The collimatable secondary gives it away. Its possible the primary being coated on the back is merely to protect the coating from physical damage. Not a bad practive, except it is another optical surface for the light to pass through (twice, actually). Questar did something similar with the early 3.5"ers, but for a different reason. They put the secondary spot on the front of the meniscus instead of the back like they currently do to avoid patent infringement of Dmitri Maksutov's design. I think the patent ran out in 1961, and they started putting the secondary on the back.

I'd say this might be just a regular ATMed scope, not necessarily a 'prototype' from a company. The open frame certainly aids in cooldown time. With no baffle tube, there might be some glare issues on bright objects.

It looks like an interesting item. Let us know how it performs.

Keith

#8 BHunt

BHunt

    Apollo

  • *****
  • Posts: 1387
  • Joined: 31 Dec 2006

Posted 21 June 2007 - 05:45 PM

Interesting history Keith. I think Galakuma would agree. You are American telescope mania.
By the way your buddy is at it again on Ebay.
Bill

#9 trainsktg

trainsktg

    Aurora

  • *****
  • Posts: 4983
  • Joined: 23 Aug 2005

Posted 21 June 2007 - 06:22 PM

By the way your buddy is at it again on Ebay


Thanks! I haven't seen any activity from him in a while. I was beginning to worry. Well, gotta run...I must go check the latest goodies out.

Keith


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics