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
Doppler Imaging

A technique that uses high-resolution spectrographic data of a star to produce a map of the star’s surface.

Main sequence star

A main sequence star is one that is in a stable part of its life converting hydrogen and helium through nuclear fusion. Most stars we see in the night sky are in the main sequence stage and our Sun is currently also a main sequence star.


This is when an atom is stripped of or receives electrons. It often happens in astronomy where a gaseous nebula is ionized by stars within it.

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