|
I'll also try yo put it simply, in a way you can apply to other scopes.
The ability to see DSOs with greater degrees of clarity depends on two main factors tha t you can control (there are other factors that you cannot control as well, but more about that later)
Magnification
Quantity of Light gathered.
Magnification is a mathematical relationship between the Focal Length of the scope and the number on the eyepiece. Mag = Focal length / eyepiece.
However, the highest possible magnification you can reasonably expect to be able focus on is generally said to be two times the aperture (in mm)
(And this drops as the environment conditions deteriorate)
So you can see that the 90mm SLT could at best deliver a magnification of 180 times, where the 10 inch DOB (250mm) could get you up near 500 times magnification.
Now admitedly you don't use that sort of magnification with DSO's generally, but the principle is that you will get more light gathering at any magnification and the more light you get the more likely you are to see your DSO.
As previously said, you really should come to an observing night and you will clearly see what I mean. We have a good range at the Pony Club, its friendly informative informal and FREE.
Hope to see you there.
|