Raw frames courtesy of Deep Sky West Remote Observatory in New Mexico, USA. (deepskywest.com) Data obtained with FSQ 106EDXiii / QSI683wsg / Lodestar / Paramount MyT.

21 hrs total integration (19x300s R, 14x300s G, 18x300s B, and 55x900s L). The palette is RGB with Luminance channel for detail.

Processing in PixInsight.

Image on left from New Mexico dark site and 21 hrs of integration. Image on right from my backyard and 1.4 hrs of integration. But to compare apples to apples, we need to scale by our respective apertures. Since my aperture is twice as large as the telescope in New Mexico, my effective comparable exposure would be 5.6 hrs.

Both images have been scaled and registered to the same plate scale for comparison.

So the effective exposure in the New Mexico image is about 4x longer than my backyard image. But the New Mexico site is also at least 2 mag darker than my home site. That's equivalent to another 6x times longer exposure. Hence, the New Mexico image is effectively 24 times deeper (or more). Don't forget that their seeing is also at least twice as good as mine (half the star diameter on avearge). Call that another factor of 2, making the dark site image about 50x deeper than I could go in an hour on my C8 HyperStar. Ahh... the benefits of robots...

oops!... if their site is 6x darker than mine (2 mag), then I have to integrate 36 times longer to get to the same average background noise level. Heh! So now we go another 6x times 50x, making the NM image 300x deeper than my own. I'd have to integrate a total of 420 hours on my C8 HyperStar to get an equivalent image in my backyard. That's about 2 solid months of clear 8 hour nights.

... and my stars would still be at least twice as large...

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Now that I know there is IFN in this image, I re-did my own data from the backyard, and did not remove all the crud near the noise floor that I thought was camera artifacts. You can now just barely see a hint of the IFN clouds in the image near to M81. And that little blue smudge just below M81 is real - not some star glint. Maybe I should trust what my camera shows me more than I have.