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
Optical double star

An optical double star is actually two stars that appear to be close to each other on the sky. In fact they are not at all related and appear close only because they lie close to each other along our line of sight.

Hydrogen-alpha filter

A type of optical filter that’s used for observing the Sun. It blocks all wavelengths of light except for a very narrow portion at 656.3nm.

Convection cells

These are huge ‘bubbles’ (some the size of Jupiter) under the surface of the Sun, caused by the rising and sinking of super-hot gas in the Sun’s interior. Smaller convection cells cause ‘granules’ on the surface. These can be observed with a specially filtered H-alpha telescope.

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