Astronomy for Beginners

Here’s where you’ll find observing guides, how-to articles and great astronomy hints and tips. Don’t forget to also check out our comprehensive astronomy dictionary.

Astronomy Dictionary
Lenticular galaxy

A lenticular galaxy (also known as a S0 type galaxy) is a galaxy that is disc shaped with no real evidence of spiral arms. Their name derives from how they look when they are edge on – like the shape of a lens.

Field stop

The field stop is the physical size of aperture available to look through on any given eyepiece.


The period during a transit or an eclipse when the smaller celestial body begins to cross the disc of the larger object. Egress marks the exit of the transiting or eclipsing body.

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