Figure 6. To find Polaris in the night sky, look north and find the Big‑Dipper. Extend an imaginary line from the two “Pointer Stars” in the bowl of the Big Dipper. Go about five times the distance between those stars and you’ll reach Polaris, which lies within 1° of the north celestial pole (NCP).
Big Dipper
(in Ursa Major)
PointerStars
Little Dipper
(in Ursa Minor)
N.C.P.
Polaris
Cassiopeia
Focusing the Finder Scope
If, when looking through the finder scope, the images appear somewhat out of focus, you will need to refocus the finder scope for your eyes. Loosen the lock ring located behind the objective lens cell on the body of the finder scope (see Figure 3a). Back the lock ring off by a few turns, for now. Refocus the finder scope on a distant object by threading the objective lens cell in or out on the finder scope body. Precise focusing will be achieved by focusing the finder scope on a bright star. Once the image appears sharp, retighten the lock ring behind the objective lens cell. The finder scope’s focus should not need to be adjusted again.
5.Setting Up and Using the Equatorial Mount
When you look at the night sky, you no doubt have noticed that the stars appear to move slowly from east to west over time. That apparent motion is caused by the Earth’s rota- tion (from west to east). An equatorial mount (Figure 2) is designed to compensate for that motion, allowing you to easily “track” the movement of astronomical objects, thereby keeping them from drifting out of the telescope’s field of view while you’re observing.
This is accomplished by slowly rotating the telescope on its right ascension (R.A.) axis, using only the R.A.
Polar Alignment
For Northern Hemisphere observers, approximate polar alignment is achieved by pointing the mount’s R.A. axis at the North Star, or Polaris. It lies within 1° of the north celes- tial pole (NCP), which is an extension of the Earth’s rota- tional axis out into space. Stars in the Northern Hemisphere appear to revolve around the NCP.
To find Polaris in the sky, look north and locate the pattern of the Big Dipper (Figure 6). The two stars at the end of the “bowl” of the Big Dipper point right to Polaris.
Observers in the Southern Hemisphere aren’t so fortunate to have a bright star so near the south celestial pole (SCP). The star Sigma Octantis lies about 1° from the SCP, but it is barely visible with the naked eye (magnitude 5.5).
For general visual observation, an approximate polar align- ment is sufficient.
1.Level the equatorial mount by adjusting the length of the three tripod legs.
2.Loosen the latitude lock
3.Loosen the Dec. lock knob and rotate the telescope opti- cal tube until it is parallel with the R.A. axis, as it is in Figure 1. The pointer on the Dec. setting circle should read 90°. Retighten the Dec. lock lever.
4.Loosen the azimuth lock knob at the base of the equato- rial mount and rotate the mount so the telescope tube (and R.A. axis) points roughly at Polaris. If you cannot see Polaris directly from your observing site, consult a compass and rotate the mount so the telescope points North. Retighten the azimuth lock knob.
The equatorial mount is now polar aligned for casual observ- ing. More precise polar alignment is recommended for astro- photography.
From this point on in your observing session, you should not make any further adjustments in the azimuth or the latitude of the mount, nor should you move the tripod. Doing so will undo the polar alignment. The telescope should be moved only about its R.A. and Dec. axes.
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