How Do You Use A Telescope With Setting Circles?
Setting circles on a telescope mount aid in locating objects in the sky. There will be two circles. One, the right ascension axis (RA for short), corresponds to the polar axis. Right ascension axes are typically measured in hours and minutes, but can also be measured in degrees. The other circle is the declination axis (DEC for short). Declination is the number of degrees off the celestial equator that an object appears. The Pole Star is near declination 90. Use setting circles when you know the coordinates of the object. Coordinates can be obtained from star charts and tables of objects in the sky. Make sure your telescope is polar aligned before you use the setting circles. (See “How to Polar Align a Telescope” in the Related eHows.) Locate a known star that is not too far from the object being sought. The star should be easy to spot and listed in a catalog or star chart. Look up the coordinates of the star (or determine them from a star chart). The more accurate the coordinates, the
