Editing Glossary (section)

===== Polar alignment =====
----In equatorial mounts (the type you should be using for deep sky) the tracking axis (right ascension) must be aligned with the polar axis of the earth. If you think about how the earth rotates and gives the stars the appearance of movement the equatorial mount moves at the same rate in the opposite direction, cancelling out the movement. It's important that the axes are exactly aligned so the tracking is dead on. If the polar alignment is not correct it can cause trailing of the stars in your image and eventually the target will drift out of the field of view. If you'd like to know more about how to do a [http://www.reddit.com/r/astrophotography/wiki/polar_alignment polar alignment read the full article here].