3.2.
Polar alignment with the provided Polarscope
The M-zero LHQ comes provided with a Celestron Polarscope. The picture below shows the
polarscope reticle. For an accurate polar alignment with Avalon Instruments mounts it doesn’t
matter for the constellation position. The reference point it will be the small circle that represent
the Polaris position or a defined degree in the graduated circle.
It is well known that the Polaris is at about 40 arcmin distance from the Celestial Pole and
therefore it orbits around the pole at that distance every about 24 hours. The cross in the reticle
center indicates the position of the Pole. The circle around it represents the orbit of Polaris. The
small circle on the orbit represents the variable Polaris position. The problem here is to position
the smaller circle at the correct Polaris angle as it is seen from the observation site at the
observation date and time. Years ago this position was obtained using several types of circular
dials and performing few calculations.
Currently the most common method to get the exact position of Polaris is using one of several
available computer programs or, better, mobile device applications. These programs provide the
position of Polaris both visually and in the hourly format as described in section 5.3.3. Once the
Polaris position has been determined in terms of hour angle, the polar scope should be rotated to
bring the small circle in that position. With this type of reticle this operation is approximate, but
is accurate enough and is satisfactory for most applications.
The small circle representing Polaris must be put in the annulus corresponding with that hour,
starting with the 0 of the annulus in the upper position.
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Celestron polarscope reticle
