Ad Astra Observatory

With most beginner astrophotography, a desire for fast optics (and the resulting short exposure lengths) is paramount.

Unfortunately, fast optics necessarily mean wider FOV. This is not a problem when you have a teeny tiny CCD, but if you’re trying to shoot galaxies, for instance, more FOV than 20′ (that’s 1/3°) is going to be wasted, since only the half-dozen largest galaxies are that big.

In fact, to get into serious galaxy shooting, you have to restrict yourself to an FOV of ~10′. So you either need a *very* big scope, or you need to sacrifice f/ratio to get the magnification you need.

Deciding that you can handle f/10 (rather than the 4x as fast f/5) opens up a whole new world of high-magnification imaging. Anytime you need a little more magnification, just jump up to the next size of SCT.