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I have three EQ mounts of different types they all have two sets of numbers on the setting circle. However one set is just the inverse of the other and one set of numbers could also be used but will invlove a little more calculation. The esential thing to remember is that the observable position of a given RA is a function of Hour angle and local sidereal time
Hour angle = LST - Right ascension
Note that Hour angle and RA are measured in opposite directions at the equator. This is why there are two scales. One the inverse of the other.
However the easiest way to use the scale is to set the one that increases towards the east with the sidereal time at the meridian and read the RA off the other. If there is only one scale you will need to subtract on of the readings from 24.
Barry
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