View cloud cover over the UK in the latest satellite image from the Met Office

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
Bi-polar outflow

When stars are born they begin to form jets at their poles known as bi-polar outflows. These jets are thought to originate from material that collapsed onto the star as it was forming. They may, in fact, be crucial to the process.

Apochromat

A telescope that is almost completely free from chromatic aberrations. These are caused in some telescopes by different wavelengths being brought to focus at different distances.

Magnitude

The brightness of an astronomical body. The lower the number the brighter it is. Magnitudes brighter than 0 are represented with a negative number.