Getting Started

There are lots of different equipment configurations with which you can do RSpec spectroscopy. Below are some suggestions. We haven’t tried them all, but these are the kinds of approaches we’ve seen in use.

Are you new to spectroscopy? An RSpec user, Iain Petrie, has written a very valuable, two-part introduction to the field. Read his posts from the bottom of each page to the top for chronological order. Set one: link. Set two: link.

Have questions? Fill in our contact form (link) to have our Help Desk experts email you. We specialize in getting newcomers up and going.

Also, see the short video here to see information about the free webinars that Field Tested Systems offers. These webinars are a complete introduction to the fundamentals of spectroscopy, the equipment needed and the kinds of scientific results you can expect.

Here’s what you need to get started in the field of telescope spectroscopy:

1. RSpec software: you can download a free, fully-enabled 30-day trial version of RSpec from this link. If your trial period runs out, just send us an email and we’ll be happy to provide you with an extension. You can also purchase a copy in our store: link. Even without clear skies or the necessary diffraction grating, you can get started today with the trial version and our sample video file you can download by clicking on this link. A sample single frame image from the video: link. This is a .bmp file, but RSpec hands FITS files too!

Also see link for sample files and a YouTube video of a workshop Tom gave on processing.

2. Diffraction Grating: We recommend the Star Analyser 100. It comes mounted in a standard 1.25” filter cell which screws into your CCD imaging camera, your telescope’s filter wheel, or the nosepiece of your video camera, or your DSLR. With 100 lines/mm, the Star Analyser 100 was specially designed amateur spectroscopy. Details: link.


RSpec can process real-time video, or FITs, JPGs, BMPs, TIFs, RAW files from any source including DSLRs and your current astronomical CCD.

Video Cameras: RSpec can process static images, or real-time video. If you want to do real-time video, you’ll need a DirectX-capable video camera. We recommend the ZWO ASI120MC Color Astronomy Camera ($199, link) as a good planetary and spectroscopy camera. Just screw your diffraction grating into the nose of the camera and you’re ready to go! The Celestron Neximage Burst Color camera ($199, link) also works right out of the box with our Star Analyser grating. (Sensor distance is 44mm.)

RSpec can also show live video spectra from Imaging source cameras, Mallincams, Orion All-in-One camera (using their Live Broadcast/WDM drivers), and the QHY5-II series and QHY5-III series of cameras.

Have a DSLR?  Use to use RSpec with a live DirectX feed from your DSLR.

Mono or color? If you’re doing public outreach or teaching with RSpec, we recommend a color video camera  so that the RSpec video preview of the spectrum is the more interesting and intuitive rainbow rather than just black and white. Mono cameras can produce more detailed spectra and are more sensitive, but a grey smudge is a lot less engaging to newcomers than a colorful, rainbow spectrum.

If you already have a astronomical video camera that you use with your telescope, if it can accommodate a 1.25″ filter cell for the diffraction grating then you probably have all you need. To get the best spectra, the grating should be located at the optimal distance from the CCD chip – see our calculator (link) and read about spacers at this link.

RSpec can be used with a variety of astronomical video cameras like the Mintron, Mallicam, ZWO, Imaging Source, Stellacam and Watec.

Note: beware of the Orion Starshoot Solar System Camera. This camera’s driver turns off the screen if not enough pixels are illuminated. This is a good design when imaging bright, large solar system objects. However, on the sparse, dim star fields we see when capturing spectra, this camera’s driver turns off the camera, preventing you from capturing spectra data.


Using your DSLR as a live video camera: The Canon 450d and other DSLRs can generate live video. With many cameras, the addition of an inexpensive converter (to DirectX/DirectShow) lets you feed real-time video from your camera into RSpec. This configuration can get remarkably good results and is extremely simple to setup.

Still Cameras: Although real-time spectroscopy using live video is easier and considerably more exciting, a standard astronomical FITS camera will allow you to capture dimmer objects.


Have an astronomical FITS camera already?  RSpec will read and process FITS images from any camera. Looking to upgrade your camera or buy a new one?  Cameras like the popular Atik 314L+ cooled astronomy camera (link) to the left often work “out of the box” with no modifications.

With many cameras, you simply thread our 1.25″ Star Analyser 100 grating into the nose piece threads of the camera. If you’re using a filter wheel, you can use our Star Analyser 200 grating. For more information on gratings, see this link.


RSpec can process RAW, JPG, and BMP images from a DSLR. You can configure RSpec to automatically load each new image file as your camera saves them to a specific folder on your hard disk. We offer special adapters ($38) to mount a grating on your DSLR: link.

Some users have gotten good results with the Canon Rebel DSLR family using the EOS utility. To avoid huge files, stay with the S .jpg format. There are plenty of pixels and resolution in S .jpg to create good spectra. And S .jpg has the advantage of seeing dimmer objects for the same exposure because of internal camera binning. (And, of course, if your DSLR can produce .avi DirectX video files, RSpec should be able to play them back.) You’ll need a DSLR to telescope adapter that can allows the diffraction grating to be threaded on at the proper distance. Or, use your grating with a DSLR: link.

Computer: RSpec’s real-time video processing won’t run very smoothly on a 10 year-old laptop! Before purchasing RSpec, we suggest you try the trial version to confirm that your computer has the necessary horsepower. If you’re planning to do real-time video spectroscopy, experiment the sample video files we provide (link). If you can play the video, rotate it, smoothly adjust the capture box, and use the histogram (3rd toolbar button), then your computer is adequate. Also, of course, if you’re planning on doing video spectroscopy, you’ll need to confirm that your computer can play the video stream coming from your camera into RSpec.

As always, we’re happy to answer any questions you may have. Please forgive us for suggesting one last time: use our contact form (link) to contact us. We love answering questions!

Also, our Yahoo forum is a great source of information: link.

And, once you get a working setup, it would be great if you shared the details with other forum members. We’d love to see a photo or two of your grating and camera on your telescope. And don’t forget to show us a screen capture of your actual profile results!