Jump to content


Photo

A 7inch F/3 Schmidt Camera

  • Please log in to reply
11 replies to this topic

#1 Charlie Hein

Charlie Hein

    Voyager 1

  • *****
  • Administrators
  • Posts: 12308
  • Joined: 02 Nov 2003
  • Loc: 26.06.08N, +80.23.08W

Posted 14 June 2014 - 11:03 AM

A 7inch F/3 Schmidt Camera

By David Cartwright

#2 Starhawk

Starhawk

    Space Ranger

  • *****
  • Posts: 5507
  • Joined: 16 Sep 2008
  • Loc: Tucson, Arizona

Posted 16 June 2014 - 08:55 AM

There is another correction possible by putting a Plano-convex lens right in front of the detector. This was done on the 30" Schmidt the University of Arizona operates on Mt. Bigelow to put a CCD detector in it. Of course, the problem there is the corrector is right in front of the detector, meaning that camera goes in there and stays in there.

The more practical modern alternative is, of course, Hyperstar. If one could make a Schmidt larger than 14" which would be compatible with the C14 Hyperstar, that would be a neat trick.

-Rich

#3 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 16 June 2014 - 06:57 PM

Great article
I got celestron sc5.5
F1.6
converted to ccd
film handling was just to difficult

#4 coinboy1

coinboy1

    Messenger

  • *****
  • Posts: 460
  • Joined: 03 May 2011
  • Loc: Tulsa, OK

Posted 17 June 2014 - 12:38 AM

Totally awesome article! Will keep this great article saved. Such good information, not many people can make schmidt correctors!!

#5 davidc135

davidc135

    Lift Off

  • -----
  • Posts: 18
  • Joined: 28 May 2014

Posted 17 June 2014 - 05:29 PM

Thanks Starhawk, highfnum and coinboy 1 for your comments and suggestions. For now, I'd like to make use of the Schmidt's potentially huge field of view. Try to make the film holder as user friendly as possible. And thermally stabilise the focal surface.
But it's always likely to be a pain in the neck, so I'm interested in the field flattener ideas. highfnum, how did your Schmidt ccd conversion work out? I'd sort of assumed, without looking much into it, that the flattener couldn't get close enough to the focal surface to work properly. Is there a plan of the hyperstar somewhere?
David

Edit Just looked up Hyperstar - impressive

#6 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 17 June 2014 - 07:28 PM

Ccd worked fine
corrector lens was not needed
ccd was half inch

#7 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 18 June 2014 - 06:08 AM

here is a shot

http://www.cloudynig...php?photo=23934

#8 davidc135

davidc135

    Lift Off

  • -----
  • Posts: 18
  • Joined: 28 May 2014

Posted 18 June 2014 - 12:27 PM

How long was the exposure(s)? I don't suppose it takes long for the nebulosity to be recorded at F/1.5.
David

#9 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 18 June 2014 - 01:16 PM

dont exacly remember was less than 1 min
likely 35 seconds
single shot tracked but no guiding

#10 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 18 June 2014 - 01:20 PM

here is one more

Attached Files



#11 davidc135

davidc135

    Lift Off

  • -----
  • Posts: 18
  • Joined: 28 May 2014

Posted 18 June 2014 - 06:55 PM

Nice photos, thanks highfnum.
David

#12 highfnum

highfnum

    Vanguard

  • *****
  • Posts: 2408
  • Joined: 06 Sep 2006
  • Loc: NE USA

Posted 18 June 2014 - 08:41 PM

Thx
I wish Ce lestron would come up
with a sc5 that built in ccd camera






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics