Orion 9829 instruction manual Specifications, Confused About Pointing the Telescope?

a.b.

c.d.

Figure 10. This illustration show the telescope pointed in the the four cardinal directions (a) north, (b) south, (c) east, (d) west. Note that the tripod and mount have ot been moved; only the telescope tube has been moved on the R.A. and Dec. axes.

Confused About Pointing the Telescope?

Beginners occasionally experience some confusion about how to point the telescope overhead or in other directions. In Figure 1 the telescope is pointed north as it would be during polar alignment. The counterweight shaft is oriented down- ward. But it will not look like that when the telescope is pointed in other directions. Let’s say you want to view an object that is directly overhead, at the zenith. How do you do it?

DO NOT make any adjustment to the latitude adjustment L-bolts. That will spoil the mount’s polar alignment. Remem­ ber, once the mount is polar aligned, the telescope should be moved only on the R.A. and Dec. axes. To point the scope overhead, first loosen the R.A. lock lever and rotate the tele- scope on the right ascension axis until the counterweight shaft is horizontal (parallel to the ground). Then loosen the Dec. lock lever and rotate the telescope until it is pointing

straight overhead. The counterweight shaft is still horizontal. Then retighten both lock levers.

What if you need to aim the telescope directly north, but at an object that is nearer to the horizon than Polaris? You can’t do it with the counterweights down as pictured in Figure 1. Again, you have to rotate the scope in right ascension so that the counterweight shaft is positioned horizontally. Then rotate the scope in declination so it points to where you want it near the horizon.

To point the telescope directly south, the counterweight shaft should again be horizontal. Then you simply rotate the scope on the declination axis until it points in the south direction.

To point the telescope to the east or west, or in other direc- tions, you rotate the telescope on its right ascension and dec- lination axes. Depending on the altitude of the object you want to observe, the counterweight shaft will be oriented some- where between vertical and horizontal.

Figure 10 illustrates how the telescope will look when pointed at the four cardinal directions: north, south, east and west.

The key things to remember when pointing the telescope are that a) you only move it in right ascension and declination, not in azimuth or latitude (altitude), and b) the counterweight and shaft will not always appear as it does in Figure 1. In fact it almost never will!

7. Specifications

Mount: German equatorial

Tripod: Aluminum

Weight: 29 lbs. 8 oz.

Counterweight: Large, 7 lbs. 9 oz. ; Small 4 lbs.

Slow-motion adjustment: R.A. and Dec. axes

Setting circles: R.A. scaled in 10 min. increments, Dec. scaled in 2° increments for N or S hemisphere

Polar axis latitude adjustment: 5° to 75°

Polar axis finder scope: Optional

Motor drives: Optional

9