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.
Like the previous method, this gets you close to the pole but not directly on it. The following methods help improve your accuracy for more serious observations and photography.
Finding the North Celestial Pole
In each hemisphere, there is a point in the sky around which all the other stars appear to rotate. These points are called the celestial poles and are named for the hemisphere in which they reside. For example, in the northern hemisphere all stars move around the north celestial pole. When the telescope's polar axis is pointed at the celestial pole, it is parallel to the Earth's rotational axis.
| Many methods of polar alignment require that you know how to find the celestial pole by |
| identifying stars in the area. For those in the northern hemisphere, finding the celestial pole is |
| not too difficult. Fortunately, we have a naked eye star less than a degree away. This star, |
| Polaris, is the end star in the handle of the Little Dipper. Since the Little Dipper (technically |
| called Ursa Minor) is not one of the brightest constellations in the sky, it may be difficult to |
| locate from urban areas. If this is the case, use the two end stars in the bowl of the Big Dipper |
| (the pointer stars). Draw an imaginary line through them toward the Little Dipper. They point |
| to Polaris (see Figure |
| throughout the course of the night (see Figure |
| (i.e., near the horizon), it may be difficult to locate. During these times, look for Cassiopeia |
| (see Figure |
| northern hemisphere. The stars around the south celestial pole are not nearly as bright as those |
| around the north. The closest star that is relatively bright is Sigma Octantis. This star is just |
Definition | within naked eye limit (magnitude 5.5) and lies about 59 arc minutes from the pole. |
| The north celestial pole is the point in the northern hemisphere around which all |
| stars appear to rotate. The counterpart in the southern hemisphere is referred to as |
| the south celestial pole. |
Figure 5-4 The position of the
Big Dipper changes
throughout the year and the
night.
Figure
The two stars in the front of the bowl of the Big Dipper point to Polaris which is less than one degree from the true (north) celestial pole. Cassiopeia, the “W” shaped constellation, is on the opposite side of the pole from the Big Dipper. The North Celestial Pole (N.C.P.) is marked by the “+” sign.
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