Meade LX200 instruction manual toc 2. Lining Up with the Celestial Pole

Meade Instruments Corporation - Meade LX200 Instruction Manuals

[ toc ] 2. Lining Up with the Celestial Pole

Objects in the sky appear to revolve around the celestial pole. (Actually, celestial objects are essentially "fixed," and their apparent motion is caused by the Earth's axial rotation). During any 24 hour period, stars make one complete revolution about the pole, making concentric circles with the pole at the center. By lining up the telescope's polar axis with the North Celestial Pole (or for observers located in Earth's Southern Hemisphere with the South Celestial Pole. See section G. Mode Functions) astronomical objects may be followed, or tracked, simply by moving the telescope about one axis, the polar axis. In the case of the Meade LX200 7", 8", 10", and 12" Schmidt-Cassegrain telescopes, this tracking may be accomplished automatically with the electric motor drive.

If the telescope is reasonably well aligned with the pole, therefore, very little use of the telescope's Declination slow motion control is necessary–virtually all of the required telescope tracking will be in Right Ascension. (If the telescope were perfectly aligned with the pole, no Declination tracking of stellar objects would be required). For the purposes of casual visual telescopic observations, lining up the telescope's polar axis to within a degree or two of the pole is more than sufficient: with this level of pointing accuracy, the telescope's motor drive will track accurately and keep objects in the telescopic field of view for perhaps 20 to 30 minutes.

Begin polar aligning the telescope as soon as you can see Polaris. Finding Polaris is simple. Most people recognize the "Big Dipper." The Big Dipper has two stars that point the way to Polaris (see Fig. 21). Once Polaris is found, it is a straightforward procedure to obtain a rough polar alignment.

To line up the 7", 8", 10" or 12" LX200 with the Pole, follow this procedure:

1. Using the bubble level located on the floor of the wedge, adjust the tripod legs so that the telescope/

http://www.meade.com/manuals/lx200/apxb.html (3 of 6) [7/29/2002 7:28:16 AM]