right-ascension circle

right-ascension circle

The setting circle on the polar axis of an equatorial mounting that measures the right ascension at which the telescope is set.
References in periodicals archive ?
As is typical of German equatorial mounts, the right-ascension circle is not coupled to the clock drive, so it must be constantly reset when the scope is being moved from one object to the next.
Turn the right-ascension circle (the slip ring) so it reads the correct value for this star.
The right-ascension circle is marked in 5-minute increments.
This procedure automatically aims the instrument at the local meridian, and you can set the mount's right-ascension circle to read the current sidereal time.
The right-ascension circle was then advanced by this amount just before swinging to a new position.