Meade LX80 Appendix D Equatorial Polar Alignment, Precise Polar Alignment, Easy Polar Alignment

Appendix D: Equatorial ( Polar Alignment)

Locating the Celestial Pole

To get basic bearings at an observing location, take note of where the Sun rises (East) and sets (West) each day. After the site is dark, face North by pointing your left shoulder toward where the Sun sets. To precisely point at the pole, find the North Star (Polaris) by using the Big Dipper as a guide (Fig. 47).

For precise tracking of astronomical objects, your telescope should be Polar aligned.

Important Note: For almost all astronomical observing requirements, approximate settings of the telescope’s latitude and polar axis are acceptable. Do not allow undue attention to precise Polar Alignment of the telescope to interfere with your basic enjoyment of the instrument.

AudioStar Polar Alignment

AudioStar provides four different methods for Polar Alignment: Easy, One-Star, Two-Star and Three Star.

Little Dipper

	Polaris
Big Dipper	Cassiopeia

Figure 47: Locating Polaris

Easy Polar Alignment

Two alignment stars are chosen by AudioStar based on the date, time and location entered. First, choose “LX80 Polar” from the “Setup: Telescope: Telescope Model” menu and place the telescope into the Polar Home Position as described on Page 28. The rest of the procedure is identical to the (alt/az) “Two-Star”.

One-Star Polar Alignment

Polar One-Star Alignment requires some knowledge of the night sky. AudioStar provides a database of bright stars and one star from this database is chosen by the observer for alignment. Polaris is chosen by AudioStar. First, choose “LX80 Polar” from the “Setup: Telescope: Telescope Model” menu and place the telescope into the Polar Home Position as described on Page 28. The rest of the procedure is almost identical to the (alt/az) One Star alt/az Alignment, except that AudioStar prompts you to point the telescope at Polaris and center it in the telescope eyepiece.

Two-Star Polar Alignment

Polar Two-Star Alignment requires some knowledge of the night sky. AudioStar provides a database of bright stars and two stars from this database are chosen by the observer for alignment. First, choose “LX80 Polar” from the “Setup: Telescope: Telescope Model” menu and place the telescope into the Polar Home Position as described on Page 28. The rest of the procedure is almost identical to the (alt/az) Two Star alt/az Alignment, Page 49.

Precise Polar Alignment

It should be emphasized that while doing casual observing, precise alignment of the telescope’s polar axis to the celestial pole is not necessary. Don’t allow a time-consuming effort at lining up with the pole to interfere with your basic enjoyment of the telescope. For long-exposure photography, however, the ground rules are quite different, and precise polar alignment is not only advisable, but almost essential.

Even though the LX80 telescopes offers a sophisticated drive system, the fewer tracking corrections required during the course of a long-exposure photograph, the better. In particular, the number of declination corrections required is a direct function of the precision of polar alignment.

Precise polar alignment requires the use of a crosshair eyepiece. The Meade Illuminated Reticle Eyepiece (see Optional Accessories, Page 52) is well-suited in this application, but it is also preferable to increase the effective magnification through the use of a 2x or 3x Barlow lens as well. Follow this procedure (particularly if the pole star is not visible), sometimes better known as the “Drift” method:

1.Obtain a rough polar alignment as described earlier. Place the illuminated reticle eyepiece (or eyepiece/ Barlow combination) into the accessory adapter of the telescope.

2.Point the telescope, with the motor drive running, at a moderately bright star near where the meridian (the North-South line passing through your local zenith) and the celestial equator intersect. For best results, the star should be located within ±30 minutes in RA of the meridian and within ±5° of the celestial equator (see Celestial Coordinates, Page 61). Pointing the telescope at a star that is straight up, with the declination set to 0°, will point the telescope in the right direction.

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