Jump to content


Photo

DIY SPECTROSCOPE

  • Please log in to reply
15 replies to this topic

#1 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 16 March 2013 - 06:04 AM

Hi All, This may have been don before, I want to make a spectroscope or is it spectrograph out of 2 camera lenses and a reflective grating, to go on my Meade RCX 10", I guide with a ZS 80II ED and Lodestar, been imaging for a good few years and want a change, is there any drawings of how to do make one.

peter

#2 gregj888

gregj888

    Viking 1

  • -----
  • Posts: 568
  • Joined: 26 Mar 2006
  • Loc: Oregon

Posted 16 March 2013 - 12:05 PM

Peter,

If you haven't found Christian's site, it's a great pace to start.

http://www.astrosurf...ectrographs.htm

My favorite:
http://home.freeuk.c...newspecold.html

Different twist- http://www.eso.org/projects/caos/

#3 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 17 March 2013 - 05:01 AM

Thanks Greg, there is a lot of info there, what I was thinking is it possible to use a CD and say a 200mm camera lens.

peter

#4 John Carruthers

John Carruthers

    Skiprat

  • *****
  • Posts: 3543
  • Joined: 02 Feb 2007
  • Loc: Kent, UK

Posted 19 March 2013 - 06:33 AM

Hi Peter, I recently made one of these;
http://www.webtreatz...7-the-g300-s...
very adaptable and easy to make, and I had most of the bits in my box.
The lenses are just 50mm bino objectives, the folding mirror came from an old etx, the grating was donated.

Attached Files



#5 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 19 March 2013 - 11:17 AM

Hi John, That looks just the sort of thing I need to get going, thanks very much for posting that, the only thing is getting a grating price is way out of OAP, need to do as you did or need to find a cheep one, got other bits.

peter

#6 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 20 March 2013 - 08:50 AM

Hi John,
Is it possible to get measurements I have managed to get nearly all bits apart from lenses.

peter

#7 gregj888

gregj888

    Viking 1

  • -----
  • Posts: 568
  • Joined: 26 Mar 2006
  • Loc: Oregon

Posted 20 March 2013 - 07:57 PM

Peter,

This might be of interest, click on the machanical button left side for drawings.

If you get all the parts, you can mach up the spectrograph on the table and take measurements from there. I use a cad program a lot too, just going from the lens FLs and camera spacings etc.

John, I like that, nice...

#8 John Carruthers

John Carruthers

    Skiprat

  • *****
  • Posts: 3543
  • Joined: 02 Feb 2007
  • Loc: Kent, UK

Posted 21 March 2013 - 03:34 AM

It depends only on the focal length of the lenses and what sort of field you need, which is dependent on the size of the sensor chip.
Simspec will help tweak your design.
I drew it out full size before assembly.
A good grating is the heart of the instrument, worth investing in. I have seen a 25mm square 300 l/mm for ~£70, I'll dig out the link.

simspec;
http://www.astrosurf...ute/compute.htm

PS
just a thought, have you tried using a bit of CD as a grating, just to get going with? Iris has a 'smile' filter to straighten out curved lines :-)

#9 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 21 March 2013 - 08:30 AM

Thanks guys, JC that link would be good.

peter

#10 John Carruthers

John Carruthers

    Skiprat

  • *****
  • Posts: 3543
  • Joined: 02 Feb 2007
  • Loc: Kent, UK

Posted 21 March 2013 - 01:47 PM

http://www.optometri...gratings_r.html
25mm x 25mm, 300l/mm ~$85 (£56).

or Edmund Sci;
http://www.edmundopt...raction-grat...

#11 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 21 March 2013 - 02:24 PM

Thanks for that CJ.

peter

#12 gregj888

gregj888

    Viking 1

  • -----
  • Posts: 568
  • Joined: 26 Mar 2006
  • Loc: Oregon

Posted 21 March 2013 - 10:29 PM

Peter,

I see I missed the link...
http://www.astrosurf...3/index-en.html

Again, click on machanicals and you can get the drawings.

Sorry

#13 John Carruthers

John Carruthers

    Skiprat

  • *****
  • Posts: 3543
  • Joined: 02 Feb 2007
  • Loc: Kent, UK

Posted 22 March 2013 - 03:44 AM

if you wish to use only one good lens try a Littrow configuration.
http://articles.adsa...000053.000.html

An easy start in spectroscopy is the transmission grating, Rainbow optics do a screw in grating filter. I just wedged a piece of grating into a T mount to get started.
Here's a write up of my experiments;
https://dl.dropbox.c... for Amateur...

Maurice Gavin (Nytecam) has successfully carried out a lot of amateur work.
Try searching his older posts.

Ken Harrison (Merlin66) has published a book on entry level spectroscopy;

Astronomical Spectroscopy for Amateurs

Series: Patrick Moore's Practical Astronomy Series

Harrison, Ken M.

1st Edition., 2011, XI, 181 p. 197 illus., 39 in color. With online files/update., Softcover

ISBN: 978-1-4419-7238-5

#14 nytecam

nytecam

    Voyager 1

  • *****
  • Posts: 11397
  • Joined: 20 Aug 2005
  • Loc: London UK

Posted 23 March 2013 - 04:45 AM

Thanks Greg, there is a lot of info there, what I was thinking is it possible to use a CD and say a 200mm camera lens. peter

Hi Peter - although the CD/DVD makes a solar spectroscope [just stare into the surface with sunlight grazing across it to see the Frouhofer lines!] it's too crude for a 'real' spectroscope as John C describes so a grating must be acquired - check out your local college or school lab for discarded parts :o

#15 p1taylor

p1taylor

    Viking 1

  • -----
  • Posts: 604
  • Joined: 19 Feb 2008
  • Loc: West Midlands UK

Posted 24 March 2013 - 03:26 PM

thanks John, Greg and Nytecam, that is very informative.

peter

#16 Mr Magoo  Happy Birthday!

Mr Magoo

    Surveyor 1

  • *****
  • Posts: 1945
  • Joined: 05 Nov 2005
  • Loc: Indiana

Posted 24 March 2013 - 06:51 PM

You should check out our own David Groski's work. Dave's solar page






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics