Meade ETX-90EC Getting Started, TELESCOPE FEATURES Quick Tips, Telescope Controls

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GETTING STARTED

CHAPTER

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TELESCOPE FEATURES

Quick Tips

•Rotational Limits: The telescope base and fork mount are designed with internal “rotational limit stops.” Thehorizontal limit stop prevents the telescope from rotating more than 630° to avoid damage to the internal wiring. The vertical limit stop prevents the viewfinder from contacting the fork mount when the telescope is pointed upward just past 90° and prevents the optical tube from contacting the base if pointed downward more than 30°. Do not force the telescope to move be yond these stops or damage to the telescope will result.

•Vertical Lock;Declination Setting Circle: The vertical lock knob (6, Fig. 1) is a knurled knob located on the fork arm to the right of the focus knob (9, Fig. 1). Mounted beneath the knob is a circular scale with no numbers. Do not confuse this scale with the Dec setting circle (18, Fig. 1) on the opposite fork arm which has a number scale used to locate astronomical objects.

•A Note on Indoor Viewing: While casual, low-power observations may be made with the telescope through an open or closed window, the best observing is always done outdoors. Temperature differences between inside and outside air and/or the low quality of most home window glass can cause blurred images through the telescope. Do not expect high-resolution imaging under these conditions.

Telescope Controls

An important array of features and manual controls facilitates operation of an ETX telescope. Be sure to become acquainted with all of these controls before attempting observations through the telescope.

Horizontal Lock (10, Fig. 1): Controls manual horizontal rotation of the telescope while sitting upright as shown in Fig.1. Turning the horizontal lock counterclockwise unlocks the telescope, enabling it to be freely rotated by hand about the horizontal axis. Turning the horizontal lock clockwise prevents the telescope from being rotated manually, but engages the horizontal motor drive clutch for Electronic Controller operation. When polar aligned, the horizontal lock serves as the Right Ascension, or R.A. lock (see Right Ascension, page 12).

Vertical Lock (6, Fig. 1): Controls manual vertical movement of the telescope while sitting upright as shown in Fig. 1. Turning the vertical lock counterclockwise unlocks the telescope enabling it to be freely rotated by hand about the vertical axis. Turning the vertical lock clockwise (to a firm feel only) prevents the telescope from being moved manually, but engages the vertical motor drive clutch for Electronic Controller operation. When polar aligned, the vertical lock serves as the Declination, or Dec lock (see Declination, page 12).

Focus Knob (9, Fig. 1): Causes a finely-controlled internal motion of the telescope’s primary mirror to achieve precise image focus. An ETX can be focused on objects from a distance of about 11.5 ft (ETX-90EC) or 15 ft (ETX-125EC) to infinity. Rotate the focus knob clockwise to focus on distant objects; counterclockwise to focus on near objects.

Flip-Mirror Control (16, Fig. 1): Both ETX models include an internal optically-flat mirror. With the flip-mirror control in the “up” position, as shown in Fig. 1, light is diverted at a 90° angle to the eyepiece. Alternately, with the flip-mirror control in the “down” position, light proceeds straight through the telescope and out the photo port (17, Fig. 1) for telephoto or astronomical photography using the optional #64 T-Adapter, or for observing with the optional #932 45° Erecting Prism (see OPTIONAL ACCESSORIES, page 17).

NOTE: The flip-mirror control is in the “up” position when the control is vertical (perpendicular to the telescope tube). It is “down” when the control is horizontal (parallel with the telescope tube).

Computer Control Panel

The computer control panel (Fig. 5) of the ETX-90EC and ETX–125EC models include a connector for either the standard-equipment Electronic Controller or the optional #497 Autostar Computer Controller, an external power supply connector, and two auxiliary ports (see OPTIONAL ACCESSORIES, page 16).

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Fig. 5: Computer Control Panel. (1) ON/OFF switch; (2) Auxiliary ports; (3) Handbox port; (4) 12v connector; (5) Power indicator light.

ON/OFF (1, Fig. 5): When the ON/OFF switch is moved to the ON position, the red power indicator light (5, Fig. 5) illuminates and power is supplied to the Electronic Controller and to the telescope’s motor drive.

AUX (2, Fig. 5): Two identical auxiliary ports provide connections for current and future Meade accessories.

CAUTION:Using products other than standard Meade accessories may cause damage to the telescope’s internal electronics and may void the Meade warranty.

HBX (3, Fig. 5): The HBX (handbox) port is designed to accept the plug from the coil cord of the Electronic Controller or the optional #497 Autostar Computer Controller.

12v (4, Fig. 5): The 12v connector is designed to accept an external power supply such as the optional #541 AC adapter or the #607 Power Cord (see OPTIONAL ACCESSORIES, page 18). When one of these alternate powering options is used, the internal batteries are disconnected from the power circuit.

NOTE: Always remove the batteries if they are not to be used for a long period of time.

Electronic Controller Functions

The Electronic Controller provides the observer with the means to control the telescope motors from a compact handbox. The Electronic Controller (Fig. 6) has soft-touch keys designed to have a positive feel, even through gloves.

Primary functions of the Electronic Controller are to move (slew) the telescope, indicate the slew speed, and to operate the optional #1244 (ETX-90EC) or #1247 (ETX-125EC) Electric Focuser (see OPTIONAL ACCESSORIES, page 18). Other functions are also possible when using the MODE key (see Electronic Controller Modes, page 11 and APPENDIX A, page 22).

Arrow Keys (1, Fig. 6): The four arrow keys slew the telescope in four directions (i.e., up-and-down or left-and-right) at any one of four slew speeds (see SPEED Key, page 7).

Important Note: While using the arrow keys to slew to an object, when reversing direction there may be a slight pause as the telescope motors compensate for the reversal of the internal gears.