Quote:
Originally Posted by Atmos
This is where it gets complicated. The ESO 2.2m is a F/8 with what I can figure out as 15.27 micron pixels (125x125mm 67megapixel sensor). Mike has a F/5 with 9 micron pixels.
In faint nebulosity the 2.2m only collects an estimated 12.5% more light per unit area. This however doesn’t take into consideration QE, the reflectivity of the ESO mirrors or scatter (the FSQ would have about 95% transmission given high quality coating and minimal dust). Given ESO likely recoat their mirrors and there is likely several corrective lens in there as well, ESO could have a 20% transmission loss without taking QE of the sensor into account.
On non stellar objects ESO and Mike are neck a neck in depth BUT ESO 2.2M does that depth at 0.18”/pixel... which is pretty amazing!
|
The camera is actually a focal reducing camera, back illuminated with a QE around 90%, and you've fatally ignored the seeing which is often as low as 0.4 arc sec for the 2.2 metre's location.......but assuming of extended objects the 2.2 metre is 10-20% better you expect to see h-alpha signal at the same locations.
You'd also expect to see the faint ESO image's galaxies (extended objects) in Mike's image...but we don't, hence I'd conclude by every measure, the ESO data is deeper.