Quote:
Originally Posted by Atmos
There are two other aspects that you can take into consideration. Was the processing of the two images the same? I'm thinking more so with the cluster than the moon.
Another one is that of noise. Even if the images do look very similar, is there a difference in measured noise? Single exposures of the moon or of stars can be quite deceptive in evaluating brightness levels.
As has been mentioned already though, reflective surfaces do lose more light than refractive ones with modern day anti-reflective coatings.
|
Nope! Same exact processing (or lack thereof). Off the SD card into Lightroom with generic import settings, crop, export, upload. No visible difference in noise, apart from the whole crop factor thing. The reflector has twice the focal length so the noise takes on a different pattern, probably easier to smooth out, but there's no reduction applied here.
I'm sure in the $2-3k and upwards OTAs they're using better coatings that reduce the gap (or so I'd hope anyway), but here in the shallow end there is literally two thirds of an f stop lost.
It's all convincing me I need to become a refractor guy. Lighter, easier, less maintenance. Less focal length, but oh well. I'll happily leave the galaxies to the big boys with more time, patience and budget than me!