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Latitude Scales
The easiest way to polar align a telescope is with a latitude scale. Unlike other methods that require you to find the celestial pole
by identifying certain stars near it, this method works off of a known constant to determine how high the polar axis should be
pointed (see figure 10).
The constant, mentioned above, is a relationship between your latitude and the angular distance the celestial pole is above the
northern (or southern) horizon; The angular distance from the northern horizon to the north celestial pole is always equal to your
latitude. To illustrate this, imagine that you are standing on the north pole, latitude +90°. The north celestial pole, which has a
declination of +90°, would be directly overhead (i.e., 90 above the horizon). Now, let’s say that you move one degree south —
your latitude is now +89° and the celestial pole is no longer directly overhead. It has moved one degree closer toward the northern
horizon. This means the pole is now 89° above the northern horizon. If you move one degree further south, the same thing
happens again. You would have to travel 70 miles north or south to change your latitude by one degree. As you can see from this
example, the distance from the northern horizon to the celestial pole is always equal to your latitude.
If you are observing from Los Angeles, which has a latitude of 34°, then the celestial pole is 34° above the northern horizon. All a
latitude scale does then is to point the polar axis of the telescope at the right elevation above the northern (or southern) horizon. To
align your telescope:
1. Make sure the polar axis of the mount is pointing due north. Use a landmark that you know faces north.
2. Adjust the mount in altitude until the latitude indicator points to your latitude. Moving the mount affects the angle the
polar axis is pointing.
This method can be done in daylight, thus eliminating the need to fumble around in the dark. Although this method does NOT put
you directly on the pole, it will limit the number of corrections you will make when tracking an object.
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Right Ascension
Setting Circle
Declination
Setting Circle
Latitude Scale
Right
Ascension
Lock
Declination
Lock
Latitude Adjustment
Screws
Figure 9 – Equatorial Head
PowerSeeker 127
This method utilizes Polaris as a guidepost to the celestial pole.
Since Polaris is less than a degree from the celestial pole, you can
simply point the polar axis of your telescope at Polaris. Although
this is by no means perfect alignment, it does get you within one
degree. Unlike the previous method, this must be done in the
dark when Polaris is visible.
1. Set the telescope up so that the polar axis is pointing north. See
Figure 10.
2. Loosen the DEC clutch knob and move the telescope so that the
tube is parallel to the polar axis. When this is done, the
declination setting circle will read +90°. If the declination setting
circle is not aligned, move the telescope so that the tube is
parallel to the polar axis.
3. Adjust the mount in altitude and/or azimuth until Polaris is in the
field of view of the finder.
4. Center Polaris in the field of the telescope using the fine
adjustment controls on the mount.
Remember, while Polar aligning, do NOT move the telescope in R.A. or DEC. You do not want to move the telescope itself,
but the polar axis. The telescope is used simply to see where the polar axis is pointing.
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