Meade LX90GPS Locating the Celestial Pole, AutoStar Polar Alignment, Easy 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. 29).

Little Dipper

Polaris

Big Dipper

Cassiopeia

IMPORTANT NOTE: In order to select any of AutoStar's three Polar Alignment options, you must first select "Polar" in the "Mount" option of the "Setup: Telescope" menu.

For precise tracking of astronomical objects, your Fig. 29: Locating Polaris. 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.

AutoStar Polar Alignment

AutoStar provides three different methods for Polar Alignment: Easy, One-Star and Two-Star.

Easy Polar Alignment

Two alignment stars are chosen by AutoStar based on the date, time, and location entered. First, choose "Polar" from the "Setup: Telescope: Mount" menu. The rest of the procedure is identical to the (Alt/Az) "TWO-STAR," page 38, except that AutoStar prompts you to point the telescope at Polaris and center it in the telescope eyepiece.

One-Star Polar Alignment

Polar One-Star Alignment requires some knowledge of the night sky. AutoStar provides a data- base of bright stars and one star from this database is chosen by the observer for alignment. Polaris is chosen by AutoStar. First, choose "Polar" from the "Setup: Telescope: Mount" menu. The rest of the procedure is almost identical to the (Alt/Az) ONE STAR ALT/AZ ALIGNMENT, page 38, except that AutoStar prompts you to point the telescope at Polaris and center it in the tel- escope eyepiece.

Two-Star Polar Alignment

Polar Two-Star Alignment requires some knowledge of the night sky. AutoStar provides a database of bright stars and two stars from this database are chosen by the observer for align- ment. First, choose "Polar" from the "Setup: Telescope: Mount" menu. The rest of the procedure is almost identical to the (Alt/Az) TWO STAR ALT/AZ ALIGNMENT, page 38.

Setting Circles

Setting circles included with the LX90 permit the location of faint celestial objects not easily found by direct visual observation. R.A. circle is located on the top surface of the telescope’s drive base. The Declination circle (11, Fig. 1) is located on the fork arm. With the telescope pointed at the North Celestial Pole, the Dec circle should read 90° (understood to mean +90°). Objects located below the 0-0 line of the Dec circle carry minus Declination coordinates. Each division of the Dec circle represents a 1° increment. The R.A. circle runs from 0hr to (but not including) 24hr, and reads in increments of 5min.

Using setting circles requires a developed technique. When using the circles for the first time, try hopping from one bright star (the calibration star) to another bright star of known coordinates. Practice moving the telescope from one easy-to-find object to another. In this way, the precision required for accurate object location becomes evident.

NOTE: You may also enter an object's R.A. and Dec coordinates using the "User: Objects" option of AutoStar's Object menu. AutoStar then automatically slews the telescope to the entered coordinates.

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