Meade ETX-70AT instruction manual Manual Operation of the Telescope without Autostar

NOTE:

For a list of magnifica- tion ratings of the eye- pieces available for the ETX-60AT and ETX-70AT telescopes, see "OPTIONAL ACCESSORIES," page 25.

The power, or magnification of a telescope is determined by the focal length of the telescope and the focal length of the eyepiece being used. To calculate eyepiece power, divide the tele- scope's focal length by the eyepiece's focal length. E.g., a 25mm eyepiece is used with the ETX-60AT. The focal length of the ETX-60AT is 350mm (see "SPECIFICATIONS," page 29).

Telescope Focal Length		=	350mm
Eyepiece Power =					= 14X
	Eyepiece Focal Length
				25mm

The eyepiece power, or magnification is therefore 14x.

Manual Operation of the Telescope without Autostar

If you wish to observe a distant land object, such as a mountain top or a bird, you can observe by merely pointing the telescope and looking through the eyepiece. Set the telescope on a table top or tripod, loosen the horizontal and vertical locks (6 and 9, Fig. 1), and turn the telescope towards the object you wish to observe. Sight along the top of the tube until you find the object. When the object appears in the eyepiece, focus the image using the by turning the focus knob (8, Fig. 1). Rotate the knob clockwise to focus on distant objects and counterclockwise to focus on nearby objects.

You can also observe stars and objects in the night sky using this method, but note that objects begin to slowly drift across the eyepiece field. This motion is caused by the rotation of the Earth. As you become familiar with Autostar operation, you can counteract the drift using the auto- matic tracking feature in the Setup menu (see "TO TRACK AN OBJECT AUTOMATICALLY," page 20), or by using Autostar's GO TO capabilities (see "GO TO SATURN," page 15).

Manual Operation of the Telescope Using Autostar's Arrow Keys

You may also observe land and astronomical objects using Autostar's Arrow keys.

If you have not already done so, prepare your telescope following the steps described in "HOW TO ASSEMBLE YOUR TELESCOPE," page 10. Next, flip the On/Off Switch (10, Fig. 1) on the computer control panel to the ON position. The copyright message lights on Autostar’s display. Press the Speed/? key (8, Fig. 3) to accept the Sun warning. The "Getting Started" message displays. Keep pressing the ENTER key (A) until "Country/State" appears on the display. (Ignore the prompts requesting "Date" and "Time" for now – these functions will be explained later in the manual).

Fig. 6: Autostar's Arrow keys.

NOTE:

Autostar requests the Country/State, City, and Telescope Model information only the first time Autostar is activated. If you wish to change this informa- tion, use the "Site" and

"Telescope Model" options in the Setup menu.

Use the Scroll keys (D) to cycle through the database of countries/states. Press ENTER (A) when your location displays. Next, use the Scroll keys (D) to scroll to the nearest city to your observing site and press ENTER. Next, use the Scroll keys (D) to scroll to your telescope model and press ENTER. The display then reads "Setup: Align."

You can now use the Arrow keys (5, Fig.

3)to slew (move) the telescope up, down, right, or left. To change the tele- scope’s slew speed, briefly press the Speed/? key (8, Fig. 3). Each press decreases the slew speed down one level, and then cycles back to the fastest speed. See page 22 for more informa- tion.

Tighten (to a "firm feel" only, do not over- tighten) the vertical and horizontal locks (6 and 9, Fig. 1). Sight along the side of the telescope’s main tube to locate an object and practice using the Autostar’s Arrow keys to center the object in the telescope’s field of view. Use the tele- scope’s focus knob (8, Fig. 1) to bring the object into focus.

This procedure demonstrates just a very small part of Autostar's capabilities. In the next section of this manual, you will begin to learn how to make use of Autostar's extensive and powerful features.

TIPS FOR BEGINNERS

Too Much Power?

Can you ever have too much power? If the type of power you’re referring to is eyepiece magnification, yes, you can! The most common mistake of the beginning observer is to “overpower” his or her tel- escope by using high magnifications which the tele- scope’s aperture and atmospheric conditions can not reasonably support. Keep in mind that a small- er, but bright and well-resolved image is far superi- or to one that is larger, but dim and poorly resolved (see below). Powers above 110X should be employed only under the steadiest atmospheric conditions.

Autostar can calculate the best eyepiece for you to use. Try out the “Eyepiece Calc” feature in the Utilities menu.

Most observers should have three or four addition- al eyepieces to achieve the full range of reasonable magnifications possible with the ETX telescopes. See “OPTIONAL ACCESSORIES,” page 25.

Fig. 7a & b: Jupiter; example of too much magnification.

Getting Started 11