Spectra captured with a DSLR are beautiful and scientific
The three stars in Orion’s Belt and their spectra
Want to use a DSLR to capture spectra? It’s easy. You can use your DSLR standalone, or mounted on a telescope. Watch the video below for details:
This video explains two ways you can use a Star Analyser with a DSLR.
Is a DSLR good enough to capture astronomical spectra?
A Wolf-Rayet star captured with a standalone DSLR. Credit: Janet Simpson: Canon 350D, EF 85mm, Star Analyser 100, and a mechanical tracking mount. 30-second exposure, F1.8, x 6 stacked, ISO 400
With a standalone DSLR, you can capture spectra like the one above. Our AD-58 adapter ($42) attaches a Star Analyser 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. But the camera’s small aperture limits the range of objects you can observe.
Also note that though it’s possible to capture spectra without a tracking mount, it can be quite challenging. We encourage you to use a tracking mount as discussed on AstroBackyard: link.
Use a Star Analyser as an "objective grating" on your DSLR's filter threads
Using a standalone DSLR is an excellent way to get started if you don’t have a telescope. And it’s great for use in educational settings.
The image below shows our AD-58 adapter holding the Star Analyser.
The AD-58 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 or any filter grating (including nebula filters, etc.)
Your Star Analyser grating (or any 1.25″ filter) screws directly into the 1.25″ inner threads of the 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 — although it’s a lot more challenging without one. 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: link.
Specifications of the AD-58 adapter
Our adapter’s outside male threads are 58 mm. They screw into the female lens cap threads on the front of a Canon DSLR lens. If you aren’t using a Canon lens, see the boxed region a few lines down this page.
The internal female threads on the adapter are 1-1/4″. You screw your Star Analyser threads into them
Adapter Rings to fit the AD-58 to your non-Canon lens cap threads.
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, the “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 lenses contain are marked with their diameter. For example, the image below indicates 58 mm diameter lens threads:
If your camera is not marked like the one above, you will need to research your specific lens. A vendor’s spec sheets often indicate the lens cap/filter thread size.
If your camera’s filter threads are less than 58 mm, you need a step-up ring: link.
If your camera’s filter threads exceed 58 mm, you need a step-down ring: link.
Also see these filter ring sets: link.
Pay particular attention to delivery times, which can vary from size to size. Also, see Adorama link and B&H link.
Questions? Please contact us using our contact form: link or visit your local camera shop and tell them you have a 58 mm filter you want to mount on your camera lens.
Use a DSLR on your telescope with our AD-T2 adapter
We also offer our AD-T2 adapter for $42. It enables you to mount a Star Analyser 100 into a 42 mm T-Ring that you already own. Refer to the photo below to see how it works. The total distance from the camera sensor to the grating when using our AD-T2 is about 60 mm.
On some camera/telescope combinations, our calculator page may show that your spectra can be improved by bringing the grating closer to the sensor. You can thread the Star Analyser onto the camera-side of the AD-T2. Then, if necessary, adding additional spacers (link) may improve results. See our calculator for more details: link.
