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argonav
member
Reged: 10/21/06
Posts: 49
Loc: Flagstaff, AZ
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I have seen two brands of Star Spectroscope eyepiece attachments for sale. Rainbo Optics and Star Analyser.
I would like to know if one gives better performance than the other for visual observing only.
thanks,
David
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Rick Woods
Postmaster
Reged: 01/27/05
Posts: 5648
Loc: Inner Solar System
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I've wondered about these too. I guess not too many people have tried them.
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- Rick
14" LX200GPS
83% of all statistics are meaningless.
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5742
Loc: London UK
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Quote:
I have seen two brands of Star Spectroscope eyepiece attachments for sale. Rainbo Optics and Star Analyser.
I would like to know if one gives better performance than the other for visual observing only.thanks,David
Suggest you post on Variable Star forum where you'll probably get some answers. I've used the Rainbow grating almost continuously for a decade with great success taking hundreds of spectra via my CCD cameras  but only a few times visually due to the poor sensitivity of the eye in this field 
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GlennLeDrew
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Reged: 06/18/08
Posts: 1250
Loc: Ottawa, Ontario, Canada
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For visual observation, you would get higher efficiency by using a prism-based spectroscope because ALL the light goes into the dispersed image. A grating, even if blazed, loses some light in the zeroth (direct) and other order images. Those employing a train of five (?) prisms cemented together work well. I've recently seen one or two models like this at Surplus Shed, although they are made for 'bench' work and would require modification. The slit mechanism must be removed and a cylindrical lens should be placed at the back end of the spectroscope so as to spread out the thin spectrum into a band havin some width.
Of course, you might be able to find a such a unit already configured for visual work at the telescope. Back in '83-'84 I purchased just such a one from Edmund, but it did cost me something like $400 (!!) back then. They'd be much less expensive today, though!
Finally, do note that *at least* an 8" scope is required so as to see spectra of anything but the brightest handful of stars.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
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Home-made Mk II RA bino, using interchangeable objectives and eyepieces
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Jack Russell
member
Reged: 03/19/07
Posts: 10
Loc: Sacramento, CA
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David,
I have used the Rainbow optics transmission grating visually a few times but my old eyes are not sensitive enough. I am planning to try my Cannon DSLR with it. Rigel Systems also offers a transmission grating http://www.rigelsys.com/
Jack
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Intes Micro M809
Intes MK66
Orion 80ED
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Asortment of UO Konigs and orthos and
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