14 replies to this topic

[lwillinger]

I have been looking at starting spectroscopy, but I know little about the subject. I have been looking at using a Star Analyzer filter with my T2i DSLR, but I do not know if the setup will suffice. I plan on doing it on only the brighter stars (magnitude 2 or brighter). My budget is $1000 USD for a spectrograph, filter, etc.
I am seeking help regarding equipment, techniques, software, etc.
Thanks!

Edited by smallbinos, 07 September 2023 - 07:12 AM.

[SeymoreStars]

What got me excited about purchasing equipment and DOING astronomical Spectroscopy was this video - https://www.youtube....h?v=Dm9HDh99y6c
I needed to understand the nuts and bolts of what I was getting into, this video was the key.

 

Note: I had the equipment and prior experience necessary for astrophotography

Edited by SeymoreStars, 07 September 2023 - 08:53 AM.

[daveco2]

I started with the rspec grating.  Just put in place of a filter.  Cost effective and works great.

Take a look at the video and website.

 

https://www.youtube....h?v=Fv5fFSacVO8

https://www.rspec-astro.com/

[SeymoreStars]

I started with the rspec grating.  Just put in place of a filter.  Cost effective and works great.

Take a look at the video and website.

 

https://www.youtube....h?v=Fv5fFSacVO8

https://www.rspec-astro.com/

I just purchased the rspec grating, it arrives on Saturday.

[robin_astro]

I started with the rspec grating.  

The Paton Hawklsey Star Analyser grating

[lwillinger]

I have also been considering the ALPY 600. What are the major differences between it and the SA100?

[robin_astro]

I have also been considering the ALPY 600. What are the major differences between it and the SA100?

The ALPY is a low resolution slit spectrograph which includes the  calibration and guide modules necessary for a complete system. The Star Analysers are just diffraction gratings mounted in standard filter cells which can be used stand alone as a very low resolution slitless spectrograph, either mounted in front of a camera lens or between camera and telescope. I originally developed it as a simple low cost entry into spectroscopy with the expectation that people would then migrate to proper spectrographs like the ALPY though it is possible to build it into configurations which can give resolutions matching the ALPY in certain circumstances.  These slides of a comparison of slitless and slit spectrographs come from my presentations at this workshop.

https://britastro.or...he-nlo-oct-2015

 

 

 

These observations show examples of using the Star Analyser in its simple low resolution setup

https://britastro.or...cabda965bfe692f

https://britastro.or...e1c6a4cf219d14d

 

and some examples of using the advantages of the ALPY spectrograph

https://britastro.or...e77e0992eb70386

https://britastro.or...31d1ec6d134b3dc

https://britastro.or...70f474be2035d42

(the last in very low resolution mode)

 

and finally some examples using the high resolution of the LHIRES  slit spectrograph

https://britastro.or...5356e4359198628

https://britastro.or...acdefe378f91ae9

https://britastro.or...8b30a0a785a7ab3

 

Cheers

Robin

Edited by robin_astro, 12 September 2023 - 08:18 AM.

[555aaa]

At the AMOS conference I noted that some teams appear to be using a transmission grating to do spectral characterization of artificial satellites.

[chrisgbedford]

I studied spectroscopy as a grad student and have been wanting to do some amateur science for a while now.  I heard about the Sol'Ex spectrometer earlier this year and decided I'd give it a go.  (The spectra on the Sol'Ex website are pretty impressive.)  You can use it to acquire solar spectra or, with the addition of a couple components, stellar spectra.  It's a slit spectrometer with a 3D-printed housing and commercially-available optics.  You can print the housing yourself or buy one a couple hundred dollars.  (I bought one.)  I've got all the components at this point but haven't had the time to assemble them and align it.  Between the housing, optics and a helical focuser I'm into it for close to $1000.  When I eventually acquire some spectra with it I'll share them here.  If you're interested, here are links to the Sol'Ex website and to vendors for the components -

 

http://www.astrosurf...ntation-en.html

 

https://telescopes.n...she-es0031.html

 

https://azur3dprints...8-couleur-rouge

[chrisgbedford]

I studied spectroscopy as a grad student and have been wanting to do some amateur science for a while now.  I heard about the Sol'Ex spectrometer earlier this year and decided I'd give it a go.  (The spectra on the Sol'Ex website are pretty impressive.)  You can use it to acquire solar spectra or, with the addition of a couple components, stellar spectra.  It's a slit spectrometer with a 3D-printed housing and commercially-available optics.  You can print the housing yourself or buy one a couple hundred dollars.  (I bought one.)  I've got all the components at this point but haven't had the time to assemble them and align it.  Between the housing, optics and a helical focuser I'm into it for close to $1000.  When I eventually acquire some spectra with it I'll share them here.  If you're interested, here are links to the Sol'Ex website and to vendors for the components -

 

http://www.astrosurf...ntation-en.html

 

https://telescopes.n...she-es0031.html

 

https://azur3dprints...8-couleur-rouge

I finally got around to assembling the hardware and collecting a few test spectra last weekend.  Christian Buil's pages at astrosurf.com as well as his YouTube videos were extremely helpful. 

[chrisgbedford]

I recorded spectra of the H-alpha and H-beta regions with my Star'Ex last weekend - scattered sunlight on a heavy overcast day.  Next up:  Integrate the spectrometer with my RC-6, work out auto-guiding, and record a spectrum of...  Vega?  I'm thinking that's the lowest degree of difficulty of the available targets. 

[akmal89]

The Paton Hawklsey Star Analyser grating

Hi,

 

I mean to ask, if any filter put in front of camera sensor, regardless, the ASI can do the plate solve. How about if the filter change to star analyzer grating. Plate solve can still work?

[robin_astro]

Hi,

 

I mean to ask, if any filter put in front of camera sensor, regardless, the ASI can do the plate solve. How about if the filter change to star analyzer grating. Plate solve can still work?

Yes I've used plate solving (Astrometry.net) and it happily ignores the spectra, solving on  the zero order star images

[akmal89]

Yes I've used plate solving (Astrometry.net) and it happily ignores the spectra, solving on  the zero order star images

I see, another silly question. Does ASIAIR have this capability (Astrometry.net) in its plate solving tab?

[pvdv]

While I don't use an Asiair, it should.

Plate-solving is just point pattern matching. Any solver works according to the same principle.

Point sources are extracted. You can use astrometry.net by simply supplying a list of x-y coordinates, plate scale and dimension.

If the focal length, pixel size, and approximate coordinates are provided, you can plate-solve extremely quickly.
If no coordinates are provided ("blind solving"),  the same applies, but the search is more computationally intensive.
If focal length and pixel size aren't provided, again, a bit more computing solves the issue.

I've never had any issue plate-solving full star-analyzer fields. To our eyes they may look very messy, but the point sources are there.

Even in Pixinsight, the most capricious solver there ever was
(FWIW, while one often hears complaints about Pixinsight plate solver, they essentially boil down to two causes 1) by default Pixinsight "trusts" the header provided coordinates and performs a near solve: this fails if the header coordinates/pixel scale aren't close enough 2) plate-solving heavily processed images with either saturated or heavily "reduced" stars prevents the software from finding what it considers point sources).