Meade 4504 instruction manual Lesson 2 Balancing the Telescope, Lesson 3 Aligning the Viewfinder

Dec

Lock

R.A.

Lock

Fig. 9a: Balancing

the telescope: the axes locks.

Counterweight shaft

parallel to floor

Fig. 9b: Balancing

the telescope.

LESSON 2: Balancing the Telescope

In order for the telescope to be stable on the tripod and also for it to move smoothly, it must be balanced. To balance the telescope, you will unlock the Right Ascension or R.A. lock (26, Fig. 2b and Fig. 9a). When this axis is unlocked, the telescope pivots more or less horizontally on the mount. This is called the R.A. axis. Later in the pro- cedure, you will also unlock the Declination or Dec lock (27, Fig. 2b and Fig. 9a). When unlocked, the telescope pivots more or less vertically on the mount. This is called the Dec axis. Most of the motion of the telescope takes place by moving about these two axes, separately or simultaneously. To obtain a fine balance of the tele- scope, follow the method below:

1.Firmly hold the optical tube secure so that it cannot accidentally swing freely. Loosen the R.A. lock (26, Fig. 2b). The optical tube now turns freely about the R.A. axis. Rotate the telescope so that the counterweight shaft (11, Fig. 2a) is parallel (horizontal) to the ground (Fig. 9b).

2.Unlock the counterweight lock knob (13, Fig. 2a) and slide the counterweight (10, Fig. 2a) along the counterweight shaft until the telescope remains in one position without tending to drift down in either direction. Then re-tighten the counterweight lock knob (13, Fig. 2a), locking the counterweight in position.

3.Again, hold onto the optical tube so that it cannot accidentally swing freely. Lock the R.A. lock (26, Fig. 2b), and unlock the Dec lock (27, Fig. 2b). The telescope now is able to move freely about the Dec axis. Loosen the cradle ring lock knobs (20, Fig. 2b) so that the main tube slides easily back and forth in the cradle rings. Move the main tube in the cradle rings until the telescope remains in one position without tending to drift down in either direction. Re-lock the Dec lock (27, Fig. 2b).

The telescope is now properly balanced on both axes. Next, the viewfinder must be aligned.

LESSON 3: Aligning the Viewfinder

The wide field of view of the 5 x 24mm viewfinder provides an easier way to initially sight objects than the main telescope's eyepiece, which has a much narrower field of view. If the 5 x 24 mm viewfinder (6, Fig. 2a) is not already attached to the telescope tube assembly, follow the procedure described in Lesson 1, step 7.

In order for the viewfinder to be functional, it must be aligned to the main telescope, so that both the viewfinder and main telescope point at the same position in the sky. This alignment makes it easier to find objects – first locate an object in the wide-field viewfinder, then look into the eyepiece of the main telescope for a detailed view.

To align the viewfinder, follow these steps. Perform steps 1 through 4 during the day- time; perform step 5 at night.

1.Remove the telescope front dust cover (8, Fig. 2a).

2.If you have not already done so, insert the low-power H 25mm eyepiece (19, Fig. 2b) into the focuser of the main telescope. See Lesson 1, step #11.

3.Unlock the R.A. lock (26, Fig. 2b) and the Dec lock (27, Fig. 2b) so that the telescope turns freely on both axes. Then point the main telescope at some well- defined and stationary land object (e.g., the top of a telephone pole) at least 200 yards distant and center the object in the telescope's eyepiece. Re-tighten the R.A and Dec locks.

4.Look through the viewfinder and loosen or tighten, as appropriate, one or more of the viewfinder bracket ring thumbscrews (7, Fig. 2a) until the viewfinder’s crosshairs are precisely centered on the object you previously centered in the main telescope's eyepiece.

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