R6 - for Astrophotography? Yup. (PICS) Locked

RLight wrote:

Wonderful work as usual.

Did I miss a part where you shot the Ra on the EF 24L and compared? Curious to see an apples to apples with the color rendition differences. I believe you, just curiosity.

I didn't see a need to compare the R6 with the Ra because the Ra is a stand-alone specialist camera and most people won't be buying it since it's a dedicated astrocam.  I was more interested in seeing if the R6 could perform for astrophotography by itself as a 'normal' mirrorless camera.  With a full frame sensor, it was inevitable that it would perform reasonably well. I think Canon just threw the Ra out there because they could.  There was no effort to backlight the buttons or add an intervalometer to the camera.  It even has face tracking and all the regular features from the EOS R on it.   But the 30x magnification and the IR-Cut modified sensor are the only notable differences between models.  Compared to the R6, the Ra is the better astro camera, but that's logical.  As for the better performer for terrestrial photography, the R6 is vastly superior with IBIS and Eye-Tracking and better video etc.
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The main problem with the EF 24mm f/1.4L II USM lens for me is that it produces a hard vignette on the EOS Ra that had to be cropped.  There was no other way to deal with the issue and it's clearly a physical difference between the camera models that is causing the problem.  Both images below are unedited (aside from image reduction before posting).  Whilst different parts of the Milky Way are visible in each image, the stronger color and crimson regions of Nebula are brighter on the Ra.  Both cameras are set with Auto White Balance.
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EOS Ra +  EF 24mmL - same EF 24mm f/1.4L II USM lens vignetted horribly.
* This image is unedited & uncropped..

EOS R6 + EF 24mmL - same lens on the R6 with same adapter produces no vignette.
* This image is unedited & uncropped.

I realize these won't be exact as setup for this stuff is a hassle. I've frozen my tail off doing enough astro to say it's a chore...

It is a chore. The drive, the setup, the risks (animals, people, insects, car accidents)... And we are just out of winter here so the temperatures are still unpleasant.

That said I'm pleased to see the R6 can double-duty for astro decently as I'm personally not going to fork up twice as although I love astro, it's another beast entirely to itself...

The EOS R6 very similar to the EOS 6D but appeared to perform with less noise than the EOS 6D.  Sensitivity is similar, possibly better.  It's really difficult to make an absolute statement without comparing them side by side and that applies to all things.
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Compared to the EOS Ra (which didn't vignette with other lenses), there was no contest.  The Ra resolved more detail, was cleaner with less noise at similar settings and produced far more vivid color on the straight-out-of-camera JPEGs.  The noise difference is even better than the R which uses the same sensor (prior to removing the IR filter).  But I'd say that the R6 is vastly superior as a terrestrial camera and you don't' have to worry about sickening shades of magenta in day-to-day shots. 
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An unedited image from the EOS Ra - straight after being taken. (EF 50mm lens)
Note the rich colors even before downloading and editing.