Meade ETX-90PE instruction manual Slew Speeds, Astronomical Observing, Observe the Moon

Enter	Go To
Arrow	Mode
keys
	Number
Help	keys
	Scroll
	keys
Fig. 21: AutoStar keys.

Tip:

When multiple choices are available within an AutoStar Menu option, the current option is usually displayed first and high- lighted by a right pointing

Slew Speeds

AutoStar has nine slew speeds that move the optical tube at rates that are directly proportional to the sidereal rate and have been calculated to accomplish specific functions. Press the Number key to change the slew speed.

The nine available speeds are:

Number Key 1	=	1x	=	1	x sidereal (0.25 arc-min/sec or 0.004°/sec)
Number Key 2	=	2x	=	2	x sidereal (0.5 arc-min/sec or 0.008°/sec)
Number Key 3	=	8x	=	8	x sidereal (2 arc-min/sec or 0.033°/sec)
Number Key 4	=	16x	=	16	x sidereal (4 arc-min/sec or 0.067°/sec)
Number Key 5	=	64x	=	64	x sidereal (16 arc-min/sec or 0.27°/sec)
Number Key 6	=	128x	=	30	arc-min/sec or 0.5°/sec
Number Key 7	=	1.0° =		60	arc-min/sec or 1.0°/sec
Number Key 8	=	1.5° =		90	arc-min/sec or 1.5°/sec
Number Key 9	=	Max =		approx. 4.5°/sec

Speeds 1, 2 or 3: Best used for fine centering of an object in the field of view of a higher power eyepiece, such as a 9mm eyepiece.

Speeds 4, 5 or 6: Enable centering of an object in the field of a low-to-moderate power eyepiece, such as a 26mm.

Speeds 7 or 8: Best used for rough centering of an object in the SmartFinder.

Speed 9: Moves the telescope quickly from one point in the sky to another.

Astronomical Observing

Used as an astronomical instrument, your telescope has many optical and electro- mechanical capabilities. It is in astronomical applications where the high level of optical performance is readily visible. The range of observable astronomical objects is limited only by the observer’s motivation.

Observe the Moon

Point your telescope at the Moon (note that the Moon is not visible every night) and practice using the Arrow keys and the slew speeds to view different features. The Moon contains many interesting features, including craters, mountain ranges and fault lines. The best time to view the Moon is during its crescent or half phase. Sunlight strikes the Moon at an angle during these periods and adds a depth to the view. No shadows are seen during a full Moon, making the overly bright surface appear flat and rather uninteresting. Try using a neutral density Moon filter when observing the Moon (see OPTIONAL ACCESSORIES, page 42). Not only does it cut down the Moon's bright glare, but it also enhances contrast, providing a more dramatic image.

To Track an Object Automatically

As the Earth rotates beneath the night sky, the stars appear to move from East to West. The speed at which the stars move is called the sidereal rate. You can setup your telescope to move at the sidereal rate so that it automatically tracks (follows) the stars and other objects in the night sky. If the telescope is not tracking an astronomical object, the object will drift out of the eyepiece field of view. The tracking function automatically keeps an object centered in the telescope’s eyepiece.

To automatically track objects, you need to learn how the AutoStar keypad operates in order to move through its menus. You'll also need to initialize and align your telescope.

Moving Through AutoStar’s Menus

The AutoStar database is organized in levels for quick and easy navigation.

•Press ENTER to go deeper into AutoStar's menu levels.

•Press MODE to move back toward the top menu level.

•Press the Scroll keys to move up and down through the options available for each level.

•Press the Arrow keys to enter characters and digits. The Arrow keys are also used to move the telescope.

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