Adapters for Star Analyser and Rainbow Optics Spectroscope gratings
You can use our Star Analyser 100 or 200 or Rainbow Optics Star Spectroscope with a DSLR to produce wonderful spectra. Although some amateurs have also gotten good results with the Rainbow Optics Spectroscope grating, we prefer the Star Analyser grating because it was designed by a knowledgeable spectroscopist. He created the Star Analyser specifically for the kind of spectroscopy done by amateur astronomers.
How to get started in spectroscopy
Have a telescope and cooled astronomical CCD camera already? Then just screw a grating into the camera nose or your filter wheel. You can easily process the resulting spectrum (rainbow) into a scientific graph using our RSpec software.
See this short Sky & Telescope video interview. Our tutorial videos (link) and active forums (link) make it easy for you to get started. You don’t have to be a post-doc researcher with a big budget. This isn’t your father’s spectroscopy anymore. These days, it’s surprisingly easy.
Using a DSLR
Below is a spectrum taken with just a DSLR showing a Wolf-Rayet star. See the Carbon emission lines? That’s the photosphere fluorescing from UV light! The photosphere on a Wolf-Rayet star is dense, high-velocity wind region surrounding the star. Even with simple equipment, you can easily spot the Carbon peaks because Doppler shift from the winds has widened them. (Wikipedia link)
(Image courtesy of Janet Simpson: Canon 350D, EF 85mm, Star Analyser 100, and an AstroTrac mount. 30 second exposure, F1.8, x 6 stacked, ISO 400)
You can capture images like this with your DSLR. The AD-58 adapter attaches a Star Analyser or Rainbow Optics grating to your DSLR lens. (See photo below.) This is called an “objective grating” configuration. It produces spectra that are two or three times better in resolution when compared to mounting your grating between a telescope and camera.
Above: Our adapter is made of black-anodized, light-weight aluminum. It screws into your DSLR lens cap/filter threads. Your grating then screws into the adapter. Use it with a Star Analyser, a Rainbow Optics Star Spectroscope, or any filter grating (including nebula filters, etc.)
Your Star Analyser or Rainbow Optics StarSpectroscope grating (or any 1.25″ filter) screws directly into the 1.25″ inner threads of our AD-58 as shown above.
For the best spectra, use with an 85 to 150 mm lens. You don’t even need a driven mount! For brighter objects, simply orient your grating so that the star-drift is perpendicular to the dispersion direction. For additional information on capturing spectra with a DSLR and tripod, see our pdf on drift spectra:
If the filter threads on your camera lens are not 58 mm, you’ll need a step-down or step-up ring.
If you order an adapter ring, “From”-end of the ring should have male threads that match your lens’ filter threads. This is generally referred to as the “first dimension.”
The “To”-end of the ring should be 58 mm female into which our AD-58 screws. And this, not surprisingly, is considered the “second dimension.”
Q. “How can I determine the diameter of my camera’s lens’ filter threads?”
A. Some lens contain an imprint that shows their diameter. For example, the image below indicates 58 mm diameter lens threads:
If your camera does not have a call-out like the one above, you will need to do some research on your specific lens. Often, vendors’ spec sheets will indicate the lens cap/filter thread size. If your camera’s filter threads are less than 58mm, you need a step up ring: link. If your camera’s filter threads are more than 58mm, you need a step down ring: link. Also see their sets: link. Pay particular attention to their delivery times, which vary from size to size. Also (although a bit more expensive) see Adorama (link) and B&H (link).
Contact us with questions (link) or visit your local camera shop and tell them you have a 58mm filter you want to mount on your camera lens.
Cost for the AD-58 is only $38 plus shipping and handling. Available now! Click here to order.
Need Custom Parts for mounting your Star Analyser on your camera?
We are big fans of PreciseParts. They’re professional, friendly, and make great custom parts. They specialize in astronomical equipment. Their site has an excellent online tool to design your custom parts. Or you can contact them directly for ordering: http://preciseparts.com.
Use our AD-T2 adapter to attach to your camera’s T-Ring
We also offer our AD-T2 adapter that mounts a grating into a 42 mm T-Ring that you already own. Refer to photo below to see how it works. Total distance from the camera sensor to the grating when using a our AD-T2 is about 70 mm. Depending on your hardware geometry additional spacers may improve the spectra: link. (The AD-T2 is not for use on webcams, whose sensors are too small for this spacing)
Cost for the AD-T2 is only $38 plus shipping and handling. Available now! Click here to order.