How to Use a Telescope With Setting Circles

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 better.

Move the setting circles to match the values obtained for the star.

Check the declination setting circle. It should require no correction. If it does, you are not polar aligned or your declination axis has slipped around its holder. Now is a good time to fix it.

Correct the RA axis. It will most likely require correction unless you are using a permanent observatory or have previously set up for another object.

Rotate the disk(s) so that the correct values for the object match on your telescope.

Look up the coordinates of the deep sky object you want to observe.

Move the telescope so that the coordinates of the telescope match those of the object. If you have done a very precise job of aligning the telescope and setting circles, the object should be in or very near your field of view.