Does such a thing exist?

[Ganymede12]

I know that astrophotographers can use diffraction gratings and filters to image a star's spectra. However, is there a filter or eyepiece that a visual observer can use to see a star's spectra? Like, look through an eyepiece and instead of seeing points of light you see each star's spectra? Or am I going stir crazy from a lack of observing ? 

[RT65CB-SWL]

Hi 'Ganymede12'.

Have you looked at http://www.patonhawksley.co.uk/ It is the only place I can think of right now!

[swamp thing]

Check this out

http://www.optcorp.com/rainbow-optics-star-spectroscope-visual-imaging.html

HTH

[niallk]

Very interesting! Would bring a whole extra dimension to observing - I like the idea... Must write my letter to Santa soon...

[Dave In Vermont]

The Paton Hawksley site has something very close to the one's from Rainbow Optics here in the US. Here's the direct link to the ones for astronomical use:

http://www.patonhawksley.co.uk/astronomicalgratings.html

I have the two-piece set from Rainbow Optics, and it works very well. Here is the link to Rainbow Optics:

http://www.starspectroscope.com/

The Rainbow offering can be used exclusively for visual use by screwing the diffraction-grating cell into an eyepiece, or the nose of a star-diagonal, and then placing the Len's Cell on top of the eyepiece. For astro, or video, photography, you need just the diffraction-grating cell. If you'd like to know more, then you might like to check out the Yahoo group for astro-spectroscopy:

https://groups.yahoo.com/neo/groups/astronomical_spectroscopy/info

And with all this - you will be well-armed to make those stars out there hand over what they are made of. Which is why I love using my astro-spectrograph - learning the composition of a star and where in it's life-cycle it was when it's light began it's journey to our eyes.

Clear & Colourful Skies,

Dave

[Ganymede12]

So it actually is possible?! You can just look through an eyepiece and see a spectra with the right equipment?

[jkwhinfrey]

You can. Great isn't it?

The Lens Cell spreads the diffraction grating spectrum out a bit so that you can see the absorption lines in the spectrum.

I have a SA100 grating that I use visually. The lines are visible in the corner of my eye but the spectrums so thin that I can't make them out directly. Pity you can buy the Lens Cell separately really. I'll just have the see if I can get hold of a suitable cylindrical lens to do the job.

I've also got an old Zeiss Amici prism device that I'm trying to get working, so it's not a new idea, but the new kit is better and cheaper.

Well worth having a go in my opinion :-)

James

[niallk]

Cool! Sounds really interesting - thanks for sharing the info. There's always a new dimension to add to this hobby

[AndyWB]

Interesting... presumably one needs tracking mount and a long focal length to isolate a star and hold it there? 

[Ganymede12]

So if I bought THIS and screwed it into the bottom of an eyepiece and looked at a star through it I would see Its spectrum? Or does this only work with cameras?

[Dave In Vermont]

The Lens-Cell from Rainbow Optics acts as both diffraction-grating and as a magnifying-glass to bring it together for visual use. The diffraction-grating alone is best suited for imaging/photographing the spectra:

http://www.starspectroscope.com/

If the link doesn't take you it, go to Rainbow Optics at the above link, and click on Product List. You'll find it.

Clear Skies,

Dave

[Ganymede12]

The two-piece set looks a bit pricey when all I would want is the filter for visual use. Anywhere I can buy one on its own?

[Ganymede12]

OK, so If I wanted to get the Rainbow Optics two-peice set, how would I do that if the site shows the price in Dollars and I only have Pounds?

[Dave In Vermont]

Perhaps you can send them an email and enquire? I would think there's a way to contact them.

Clear & Colourful Skies,

Dave

[Dave In Vermont]

I think I've found you a way. OPT is Oceanside Photographic and Telescopes. They are located in California, and I believe they will ship to the UK, And they carry the Rainbow Optics spectrographic goodies:

http://www.optcorp.com/rainbow-optics-star-spectroscope-visual-imaging.html

I suggest you send them an email. Here a link to fill out an email-form to ask them a question:

http://www.optcorp.com/contacts/

I have done a lot of business with OPT over the years. They know astronomy on an expert level. And always are eager to help and answer questions A.S.A.P. I rate them as a gold-star retailer.

Clear Skies,

Dave

[Ganymede12]

Thank for the link. I have just sent them a message with my enquiries. Hopefully I'll get a response soon. 

[Ganymede12]

I've just placed the order with them after they responded to my email. 

Knowing my luck Yellowstone will erupt before it can be shipped out

[Ganymede12]

Its here! Sort of. It took about 3 days to get from the other side of America to South Wales but it will take four days to get to me from just over the hill! (darn non-weekend delivery). I should have it Monday.

[Ganymede12]

... and it arrived on Wednesday instead.

There was a brokers tax on it which neither OPT or UPS felt that hey needed to tell me about which added another £50 on top of the £160 for the Spectroscope itself and £30 for shipping and VAT.  So it has been more expensive than anticipated. 

But its here now and I can't wait for a clear night to try it out on!

[Ganymede12]

So, the spectroscope works, I've even made some rudimentary images with it. However, I'm not seeing the absorption lines in the spectra. My chemistry teacher suggested reducing he intensity so will a lunar filter help to reduce the intensity and resolve the lines?

[PeterW]

What are you looking at? Ideally you want a bright object so you can then look for the dark lines. You might not be able to see them if the slit in your spectroscope is not thin enough, I found this when looking for Fraunhofer lines in the Suns spectrum (when looking at a cloud... Not directly at the sun!)

Cheers

PEterW

[Ganymede12]

I am Looking at Betelgeuse through the Rainbow Optics Star Spectroscope with my Skyliner 200P dobsonian and a 25mm eyepeice. I can barely see the absorption lines but when I use a webcam and sharpcap I can faintly make put one line in the orange/red area of the spectrum. 

I just tried placing a lunar filter between the diffraction grating and  the EP but that had no effect (other than a darker image). 

Something I noticed when trying to take an image was that I couldn't focus on the entire spectra at once. I either focused on one end and had it fan out at the other end or focused on the middle and have it fan  out slightly at both ends. 

Any ideas?

[Merlin66]

Visually, the absorption bands should be seen in brighter A type stars - Sirius, Vega etc.

The clarity of the lines depends on the seeing conditions and focal length of the telescope. Good seeing and lower f ratio's (around f5) will help.

The reason the spectra image doesn't focus is due to chromatic aberrations in your optical system. This is a common problem with refractors but should be suppressed in reflectors. Try the grating alone mounted in a nosepiece on your camera - no eyepiece. You should be able to get a better spectral image.

[Ganymede12]

Try the grating alone mounted in a nosepiece on your camera - no eyepiece. You should be able to get a better spectral image.

I haven't been using an eyepiece. Just the webcam, nosepiece, grating and barlow lens. I can't focus any part of the spectra without the barlow lens so I can't really remove that. 

My two telescopes are an F10 Refractor and F6 Reflector. I've been using the reflector. Visually, I use my 25mm and 26mm EPs as tthis give me the exit pupil closest to the optimul range suggested by the owners guide. 

[Merlin66]

Hmmm,

Then the chromatic aberrations you see must be coming from the barlow...