Will larger apertures produce brighter visuals?

orly_andico · Post by **orly_andico** » Tue Oct 19, 2010 2:47 am

one thing to remember is that as you go above 8" the light pollution really bites. so if you can't take it to a dark-sky site, any aperture above 8" will not do so much good...

rlow · Post by **rlow** » Tue Oct 19, 2010 7:24 am

orly_andico wrote:richard, that's what i've "read" -- colors in 18"-class scopes.

of course M42 is easy, the green is readily apparent.

For those whose eyes are sensitive, they see green tint in M42 in much smaller scopes than 18".

For many people, apart from planets and star colour, most DSOs may still appear 'monochrome' in 18" scopes.

rlow · Post by **rlow** » Tue Oct 19, 2010 7:29 am

orly_andico wrote:one thing to remember is that as you go above 8" the light pollution really bites. so if you can't take it to a dark-sky site, any aperture above 8" will not do so much good...

That's a common myth, and it's a fallacy. Bigger aperture above 8" will show more even in light-polluted skies.

Post by **weixing** » Tue Oct 19, 2010 9:07 am

Hi,
Yes. At the same magnification, a larger scope will make an image brighter compare to a small scope.

Anyway, actually, non-stellar object will appear dimmer when viewing through telescope compare to the naked eye... it's appear brighter because it's bigger and easier to see by your eye.

Have a nice day.

Chris · Post by **Chris** » Tue Oct 19, 2010 12:34 pm

Having started out with the school's 8 inch dob, I had aperture fever.

Bigger is indeed better. However, it also means more $$, and a more expensive mount to carry or track with such a heavy scope.

The weight of a 10 inch mirror alone will dissuade u from bringing the set up anywhere else (don't for get the mount).

It is always better to find a sweet spot between aperture and portability, unless u are running an observatory and don't intend to bring the scope anywhere else.

Better to get a smaller decent scope than to get something which will end up rusting in a corner at home.

Canopus Lim · Post by **Canopus Lim** » Tue Oct 19, 2010 2:23 pm

rlow wrote:
orly_andico wrote:richard, that's what i've "read" -- colors in 18"-class scopes.

of course M42 is easy, the green is readily apparent.
For those whose eyes are sensitive, they see green tint in M42 in much smaller scopes than 18".

For many people, apart from planets and star colour, most DSOs may still appear 'monochrome' in 18" scopes.

Yeah there is no need to have 18" to see colour in M42. I would think the deciding factor of seeing colour is the exit pupil (brightness), the sky transparency and darkness and how dark adapted the eye is. 1 week ago at the desert, I could see the green colour of M42 with my 10x50 binoculars (5mm exit pupil) and it was really really bright green. In fact it was blinding to my eyes.

Canopus Lim · Post by **Canopus Lim** » Tue Oct 19, 2010 2:25 pm

In singapore, we are limited in how big our pupil can go due to the light pollution (grey skies instead of black)... and in the process we are limited in seeing the colour in M42. Only when we go to real dark sites that our pupil can dilate big and take in the full exit pupil of the 5mm or 7mm binoculars or telescopes, will the bright colour of M42 be seen.