Telescope Reviews: DIY SPECTROSCOPE

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Equipment Discussions >> ATM, Optics and DIY Forum

Pages: 1

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

DIY SPECTROSCOPE
#5735596 - 03/16/13 07:04 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

Post Extras:

gregj888
sage

Reged: 03/26/06

Loc: Oregon

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5736250 - 03/16/13 01:05 PM

Peter,

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

http://www.astrosurf.com/buil/spectrographs.htm

My favorite:
http://home.freeuk.com/m.gavin/newspecold.html

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

Post Extras:

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

Re: DIY SPECTROSCOPE new

[Re: gregj888]
#5738052 - 03/17/13 06:01 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

Post Extras:

John Carruthers
Skiprat

Reged: 02/02/07

Loc: Kent, UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5742370 - 03/19/13 07:33 AM Attachment (12 downloads)

Hi Peter, I recently made one of these;
http://www.webtreatz.com/index.php/articles/34-general-articles/87-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.

Edited by John Carruthers (03/19/13 07:35 AM)

Post Extras:

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

Re: DIY SPECTROSCOPE new

[Re: John Carruthers]
#5742817 - 03/19/13 12:17 PM

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

Edited by p1taylor (03/19/13 12:22 PM)

Post Extras:

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5744764 - 03/20/13 09:50 AM

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

peter

Post Extras:

gregj888
sage

Reged: 03/26/06

Loc: Oregon

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5746270 - 03/20/13 08:57 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...

Post Extras:

John Carruthers
Skiprat

Reged: 02/02/07

Loc: Kent, UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5746883 - 03/21/13 04:34 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.com/buil/us/compute/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 :-)

Edited by John Carruthers (03/21/13 04:38 AM)

Post Extras:

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

Re: DIY SPECTROSCOPE new

[Re: John Carruthers]
#5747184 - 03/21/13 09:30 AM

Thanks guys, JC that link would be good.

peter

Post Extras:

John Carruthers
Skiprat

Reged: 02/02/07

Loc: Kent, UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5747761 - 03/21/13 02:47 PM

http://www.optometrics.com/products_gratings_r.html
25mm x 25mm, 300l/mm ~$85 (£56).

or Edmund Sci;
http://www.edmundoptics.com/optics/gratings/reflective-ruled-diffraction-grat...

Post Extras:

p1taylor
professor emeritus

Reged: 02/19/08

Loc: West Midlands UK

Re: DIY SPECTROSCOPE new

[Re: John Carruthers]
#5747841 - 03/21/13 03:24 PM

Thanks for that CJ.

peter

Post Extras:

gregj888
sage

Reged: 03/26/06

Loc: Oregon

Re: DIY SPECTROSCOPE new

[Re: gregj888]
#5748756 - 03/21/13 11:29 PM

Peter,

I see I missed the link...
http://www.astrosurf.com/thizy/lhires3/index-en.html

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

Sorry

Post Extras:

John Carruthers
Skiprat

Reged: 02/02/07

Loc: Kent, UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5749057 - 03/22/13 04:44 AM

if you wish to use only one good lens try a Littrow configuration.
http://articles.adsabs.harvard.edu//full/2011SASS...30...53G/0000053.000.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.com/u/95073912/Building%20a%20Spectrograph%20for%20Amateur...

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

Post Extras:

nytecam
Postmaster

Reged: 08/20/05

Loc: London UK

Re: DIY SPECTROSCOPE new

[Re: p1taylor]
#5751222 - 03/23/13 05:45 AM

Quote:

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