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TRUE POLE ALIGNMENT of an
OBSERVATORY CLASS EQUATORIAL

6)

Adjust Hour Axis into the Meridian

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


ON6hCIRCLE - DEC. READING HIGH - POLE END of HOUR AXIS EAST of MERIDIAN
ON
6
hCIRCLE - DEC. READING LOW- POLE END of HOUR AXIS WEST of MERIDIAN
ON
18
h CIRCLE - DEC. READING HIGH - POLE END of HOUR AXIS WEST of MERIDIAN
ON
18
h 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.