Magnetic Compass; Setting Magnetic Declination; Compass Installation - Meade LX200 Instruction Manual

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Fig. 13: Underside of Drive Base. (1) Wedge Attachment
Holes; (2) Azimuth Attachment Hole (1/2-13 thread).
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5
Fig. 14: Telescope on Wedge. (1) Tilt Plate Attachment
Knobs; (2) Telescope to Tilt Plate Attachment Knobs; (3)
Deluxe Latitude Control (DLC) Knob; (4) Altazimuth
Attachment Hole; (5) DLC Main Crossbar; (6) DLC Crossbar
Attachment Screws.
Thread one of these knobs (or screws, as appropriate) partially
into the hole on the underside of the drive base, located at the
curved-end of the drive base (4, Fig. 12). This knob or screw
should be threaded in about 3 full turns, not fully threaded into
the hole.
Check that the knobs or bolts at the side of the wedge (5, Fig. 8
or 5, Fig. 10), are firmly tightened before placing the telescope
onto the wedge.
Grasping the 2 fork arms of the telescope firmly, with the power
panel towards you, place the telescope onto the tilt plate of the
wedge by sliding the knob (7" and 8" LX200) or screw (10" and
12" LX200) into the slot at the top of the curved-end of the
wedge tilt-plate.
Insert the 2 remaining knobs for the 7" and 8" LX200, or socket
screws for the 10" and 12" LX200, through the underside of the
tilt plate and into the underside of the drive base. Tighten down
all 3 knobs or screws to a firm feel. Extreme force is not
necessary in this regard.
The telescope is now fully mounted onto the wedge and field
tripod. Adjustments in wedge latitude angle and/or azimuth
orientation may be made with the telescope in place. Further
details on telescope polar alignment see APPENDIX B, page 30.
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4. Magnetic Compass

The magnetic compass helps the observer to set-up the
telescope without actually seeing the pole star Polaris. This
allows setting up before dark or in locations where the view of
Polaris is obstructed. The magnetic compass has an
adjustment to compensate for the local angle of Magnetic
Declination. Note: Magnetic Declination is the difference
between Magnetic North (which the compass shows) and true
north (where the telescope should be pointed). Magnetic
Declination should not be confused with the astronomical term
"Declination," which, when used with "Right Ascension",
describes the celestial coordinate system.
a.

Setting Magnetic Declination

In order to obtain an accurate reading using the compass, you
must first adjust for the Magnetic Declination for your location.
1. First, determine the Magnetic Declination in your area
using the Isogonic Chart (Fig. 15)
2. Squeeze the clear central vial with thumb and index finger
of the left hand.
3. With the right hand, rotate the outer dial until the orienting
arrow (the black arrow painted on the inside clear surface)
is lined up with the desired Magnetic Declination angle on
the declination scale. Notice that East Magnetic
Declination is to the right of the "North" position and West
Magnetic Declination is left. As an example, Fig. 16 shows
the correct setting for 16 degrees West Declination, which
covers Providence, Rhode Island.
20° E — Declination — W
25°
30°
40°
50°
22°
21°
20°
19°
18°
17°
16°
15°
14°
13°
12°
11°
10°
7°
8°
9°
Fig. 15: Magnetic Declination Map.
b.

Compass Installation

The Magnetic Compass is now set for the correct declination
angle. To attach to the equatorial wedge, follow these steps:
1. Snap the Magnetic Compass into the 3" diameter wedge
attachment knob (after setting the Magnetic Declination as
described above). Position the compass into the knob so
that the 360 degree location on the direction scale (the
"North" position) lines up with one of the nine points of the
knobs. (See Fig. 16.) Press the compass firmly into the
knob.
2. Assemble the equatorial wedge onto the field tripod as
described in the Instruction
knob/compass combination to attach the wedge to the
tripod.
60°
50°
40°
30°
25°
24°
23°
22°
21°
20°
19°
18°
17°
16°
15°
14°
13°
12°
11°
10°
9°
8°
7°
6°
5°
4°
3°
2°
1°
0°
1°
2°
3°
4°
5°
6°
Manual using the