Poor Mans Spectroscope for Hard Planetary Nebulas

[dmill1220]

Hi everybody
One of my favorite objects to hunt for when I'm not taking pictures is hunting for those elusive small Planetary nebula's that are hard to distinguish from other stars.
Since my forced retirement, money for new equipment is not easy to come by nowadays, so I improvise wherever I can,

I resort to using a blackened side, right angle prism, for which I have made an enclosure for, that fits over any eyepiece that I have, this allows me to pick out those planetarys much easier since a stars spectrum can easily be seen with the prism ,and the planetary objects tend to not change, that is, visually they do not make that telltale rainbow spectrum that stars do under the prism.

I do have to use a dark towel over my head to get a good look though, but it does work!
I even made a slit for the prism by taking apart a razor blade and placing the blades very close together just under the prism.
the tricky part was getting the right angle for the prism to show the Spectra, they are real small and not very bright, so the Dark towel really helps. I now have just seen a spectroscope which is Made by Rigel Systems for only $299.95 they claim it can be used for both photographic and visual applications, the Difference is they use a grating instead of a prism. guess how much mine cost to make? $20 bucks.
OK I cant take pictures but it is effective for visual use only.

Has anyone hear played around with visual spectroscopy on the Stars?
Or does anyone know of any other Manufacturers of Astronomical Spectroscopic Equipment that you don't have to sell your Car for?
Dennis

Originally Posted by dmill1220

Has anyone hear played around with visual spectroscopy on the Stars?

I once looked at Betelgeuse through my Dob with a diffraction grating between the eyepiece and my eye. I saw many absorption bands, especially at longer wavelengths.Tried the same with Rigel and Sirius but neither was as spectacular as Betelgeuse.

Out of curiosity, what does the spectrum of a nebula look like using your prism setup? I imagine there must be some neat looking identifying characteristics?

[dmill1220]

HI Umop!
I havent tried it on any pure nebulous objects whether emission or reflective, since this is a crude method the Spectra is very faint and small with no absorption or emission lines visible, just a small Rainbow Image on stars are detectable with my prism and that's with a towel over my head!
I will try it on M-42 or M-1 it may not be bright enough!
I would assume that I will not see any rainbow for Nebulas, the Prism technique really just allows me to see which are stars ( they show a small rainbow spectrum) and just what appears to be a point source for the Planetary Nebulas
Dennis

Oh. Maybe then you are seeing nebulae giving off a narrow range of wavelengths. Since IME looking through a telescope often requires relying on scotopic (rod based) vision, colors aren't always forthcoming, but this way your device separates out wavelengths without requiring the light to be bright enough for color vision.

[dmill1220]

HI umop,
Your are correct. the spectra of a planetary is very narrow so it appears as a point source using my crude method, but the stars do show a colored Rainbow Spectrum, its just so small and faint, that no absorption or emmission lines are visible, since a lot of planetary nebulas are so small and, are hard to distinguish from background stars, this method easily allows me to differentiate which ones are stars in my field of view.
But a high Magnification is needed to see the Rainbow Spectrum of Stars using this method, the More Magnification, the more the Spread of the Stars Spectrum.
Dennis