Best DSLR or ILC for Night Sky Imaging?

Started Nov 8, 2017 | Questions thread
Astrophotographer 10 Forum Pro • Posts: 13,008
Re: Another Interesting Al Nagler Article

RustierOne wrote:

In view of all the recent discussion about how f-ratio affects image brightness, you might enjoy this brief article by Al Nagler (of Televue fame):

The Joys of Low-power Viewing

An interesting quotation from that :
"f/# Considerations

A fast f/# telescope objective will produce the same brightness as a slow telescope with the same aperture and magnification. For visual observing, the fast f/# implies a short f.l., which does give the most field. Visually, therefore, we can say that a "faster" scope has more potential field, but no more image brightness than a slow scope of the same aperture!"

The emphasis (underlining) has been added by myself. It seems that Al's viewpoint and understanding has weight in our discussion since he's a respected optical engineer and telescope user.

Interesting, yeah?

Yes there is an interesting article done quite a few years ago now, by Stan Smith of CCDStack fame.

Its called the F Ratio myth and shows examples demonstrating what Al has said.

So it comes down to aperture rules in the telescope world. Bigger apertures collect more light.


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