How can an amateur use setting circles?
Astronomer will often set up a portable telescope that is equipped with setting circles and what is often required is polar alignment, in which the telescope is aligned with the North or South celestial pole(s). The astronomer then must set the RA, after the polar alignment, using a well known star to synchronize with RA circle in sidereal time. Astronomers often have a difficult time with the accuracy of pointing with a telescope. There can be several causes for this issue: • It can be the ground the astronomer is observing on which may be uneven. • An uneven tripod. • The optical tube is not perpendicular to the declination axis. • The declination and right ascension axis are not perpendicular. • The astronomer had made errors while setting up the rotation of the setting circles. • The astronomer had made errors in reading the setting circles. Astronomers use digital setting circles (DSC) which are composed of two rotary encoders on both axis of the telescope mount and a digital read
