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Canon offered astro-modified versions of a couple of their cameras in years past, the 20Da and 60Da. Nikon in 2015 introduced the D810a, and now Canon is rumored to be making their return to the Astro camera market. These astro cameras are essentially the standard camera model with a modified IR filter that allowed more of the H-alpha light common in many nebula through to the sensor.
The down side of this filter modification is the color balance is completely ruined for standard shooting, and would need to be corrected with a separate IR-blocking filter on the lens.
While Canon’s past astro modified cameras have stopped as modifying just the IR filter on the sensor, to Nikon’s credit with the D810a, Nikon also modified the firmware to support exposures up to 15 minutes in length without any external controller. (Most DSLRs are limited to 30 seconds in-body, including past Canon Astro modified bodies.)
The rumor circulating now is that Canon will introduce an astro modified version of the EOS R, but with the only modification being to the IR cut filter. While interesting for sure, I’d actually much rather see a crop sensor (and lower priced) Astro Mirrorless camera with a modern sensor, and that they follow Nikon’s lead and allow for longer exposures and exposure sequences without an external controller.
Even for a full-frame, this should properly be an EOS RPa – the difference in features to the R vs the RP has little application to astrophotography, so you wind up paying $1000 more for extra features you don’t need. These Astro-specific cameras have also historically commanded a premium price over their standard counterparts, and rarely go on sale.
So, the big question is, do you need one of these astro-modified cameras to image nebula?
The answer is a resounding no!
While the standard cameras have an IR filter that blocks much of the H-alpha light, it still does allow enough of that light through. A stock camera is also going to provide a more true to eye color balance than a modified camera will. If you are concerned about the highest detail and nebulosity, then an astro modified camera is worth considering. At the same time, you may instead be better off looking to dedicated astro cameras, from vendors like Meade, ATIK, and ZWO, which have come down considerably in price and use similar CMOS sensors, with the benefit of active cooling. The negative for these dedicated astro cameras is of course the need to operate them from a laptop or other connected device, while a DSLR or Mirrorless camera is effectively self-contained, making for a more portable and light setup.
For those, like me, that prefer the convenience and versatility of shooting with a DSLR or Mirrorless camera, the best option is still to buy a standard model mirrorless or DSLR, and just shoot with that (Which is exactly what I do). If you really want a modified camera, there are a couple reputable vendors that offer a conversion service in the sub-$500 range. The Nikon and Canon Astro versions tend to be about 1-2 years behind their standard counterparts, so you can save money and get newer sensor technology by buying a stock camera and optionally choosing to have it modified.
While I’m very happy to see Canon return to the Astro market, and Nikon as a part of it, for me these cameras unfortunately miss the mark. Rather than their larger, heavier models, I would like to see manufacturers apply the filter modification to their smaller, more basic models. Following Nikon’s lead, minor firmware tweaks could also make these cameras much more functional for astro imaging. I do hope to see both Nikon and Canon (and hopefully Sony) offer cameras tailored to the astro market. It’s just in this case, the newer models on offer (or soon to be offered) feel over-priced and over-sized.
You may have noticed a lack of new posts here for a while. Pretty much all of my energy these last two years has been directed to Mile High Astronomy. I’m happy to say the website and brick and mortar store here in Denver, Colorado are off to a good start. I do hope to have more posts to this blog again, but they will probably still be some time between. Thank you for reading, and being a part of the community. If you find yourself in Denver, I hope to see you at the store!