i) Direct telescope to a star on the
6h/18h circle, zenith distance less than 75º

ON 6h CIRCLE
- DEC. READING HIGH - POLE END of HOUR AXIS EAST of MERIDIAN
ON 6h CIRCLE
- DEC. READING LOW - POLE END of HOUR AXIS WEST of MERIDIAN
ON 18h
CIRCLE - DEC. READING
HIGH - POLE END of HOUR AXIS WEST of MERIDIAN
ON 18h
CIRCLE - DEC. READING
LOW - POLE END of HOUR AXIS EAST of MERIDIAN

ii) Correct readings for refraction in
declination.
iii) From the apparent declination
precessed to epoch of date subtract the corrected reading.
iv) This gives the azimuth error.
v) To apply the correction adjust
the pole end of hour axis in the opposite direction to the azimuth error.
vi) Repeat and note residual azimuth
error. |