Instruction Manual ETX-90EC Astro Telescope ETX-125EC Astro Telescope Meade Instruments Corporation
0 1 2 5 Features of the ETX-90EC and ETX-125EC are identical, with the exception of the siz e of optical tube and the type of viewfinder included as standard equipment. 3 4 19 18 6 (on left fork arm) 17 7 (on both sides) 16 8 9 21 15 14 13 10 12 11 Fig. 1: The ETX-90EC Astro Telescope. 1. 2. Eyepiece Viewfinder: ETX-90EC: 8 x 21mm Erect-Image Viewfinder ETX-125EC: 8 x 25mm Right-Angle Viewfinder 3. Eyepiece holder thumbscrew 4. 90° eyepiece holder 5.
z CONTENTS WARNING! Never use a Meade® ETX® Astro Telescope to look at the Sun! Looking at or near the Sun will cause instant and irreversible damage to your eye. Eye damage is often painless, so there is no warning to the observer that damage has occurred until it is too late. Do not point the telescope or its viewfinder at or near the Sun. Do not look through the telescope or its viewfinder as it is moving. Children should always have adult supervision while observing. Quick-Start Guide . . . . . . . . .
z QUICK-START GUIDE 4 QUICKSTART GUIDE 1 A 4 B G Remove the ETX from its packaging and place it on a sturdy surface. Place the eyepiece (A) and viewfinder (B) into their appropriate positions on the telescope and tighten the appropriate attachment screws to a firm feel only. 2 E Flip the Power Switch (E) on the computer control panel to the ON position. The lights flicker on the Electronic Controller. Press any key and the motors briefly move the telescope.
z STARTED Chapter 1: GETTING INTRODUCTION A Meade ETXAstro Telescope is an extremely versatile, highresolution imaging system that, with advanced features similar to larger and more specialized telescopes, can be used by casual observers and serious astronomers alike. With pushbutton controls, automatic tracking of celestial objects (with one of the optional tripods), and diffraction-limited imaging, an ETX telescope may be all the telescope ever required by many terrestrial and astronomical observers.
z GETTING STARTED 6 TELESCOPE FEATURES CHAPTER 1 Quick Tips • Rotational Limits: The telescope base and fork mount are designed with internal “rotational limit stops.” The horizontal 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°.
z GETTING STARTED Indicator Lights (2, Fig. 6): Four red LED (Light Emitting Diode) lights are used to indicate the current slew speed. 7 any dew that might have collected during the observing session has evaporated prior to replacing the dust cap. With the standard-equipment SP 26mm eyepiece inserted in the eyepiece holder, the telescope is operating at the following power (see Understanding Magnification, page 9): • • 1 Fast 7 Medium 2 Moderate 6 Slow 3 5 4 Fig.6: Electronic Controller.
z GETTING STARTED 8 THE VIEWFINDER CHAPTER 1 As with most astronomical telescopes, both ETX model telescopes present a fairly narrow field of view to the observer. As a result it is sometimes difficult to locate and center objects in the telescope’s field of view. The viewfinder, by contrast, is a low-power, wide-field sighting scope with crosshairs that let you easily center objects in the eyepiece of the main telescope’s field of view.
Chapter 2:TELESCOPE zFUNDAMENTALS INTRODUCTION Both ETX model telescopes can be used for immediate observation right out of the box. However, becoming familiar with the fundamentals of a telescope makes subsequent viewing easier and more rewarding. Choosing an Eyepiece The function of a telescope’s eyepiece is to magnify the image formed by the telescope’s main optics. Each eyepiece has a focal length (expressed in millimeters, or “mm”). The smaller the focal length, the higher the magnification.
z FUNDAMENTALS TELESCOPE 10 surface through heat waves. These heat waves often degrade image quality. Low-power eyepieces, like the SP26mm eyepiece, magnify these heat waves less than higher-power eyepieces. Therefore, low-power eyepieces provide a steadier, higherquality image. If the image is fuzzy or ill-defined, reduce to a lower power. Observing in early morning hours, before the ground has built up internal heat, produces better viewing conditions than during late-afternoon hours.
z TELESCOPE FUNDAMENTALS THE ELECTRONIC CONTROLLER Briefly described on page 6, the Electronic Controller is the primary device used to move ETX model telescopes.
Chapter 3: POLAR ALIGNMENT 12 APTER 3 For extensive astronomical observing, the telescope is best mounted in the polar configuration. In polar alignment the telescope is oriented so that the horizontal and vertical axes of the telescope align with the celestial coordinate system (see Fig. 11). To polar align either ETX model you must understand how and where to locate celestial objects as they move across the sky.
POLAR ALIGNMENT 4. Each table tripod is equipped with two adjustable tripod legs: The standard tripod leg is used at observing latitudes as shown in the box in step 5 and has a dual latitude label attached (Fig. 15). The high-latitude tripod leg is shorter and is used at higher observing latitudes. Based on the observing latitude determined in step 3, set aside the tripod leg that is not to be used. 5. Locate the two mounting holes on the bottom of the telescope drive base.
Chapterz4: OBSERVING 14 CHAPTER OBJECTS IN SPACE 4 Listed below are some of the many astronomical objects that can be seen with either ETX model telescope. The Moon The Moon is, on average, 239,000 miles (380,000km) from Earth. It is best observed during its crescent or half phase, when sunlight strikes its surface at an angle, casting shadows and adding depth to the view (Fig. 18). Jupiter is the largest planet in our solar system, with a diameter 11 times that of Earth.
z OBSERVING PHOTOGRAPHY WITH BOTH ETX MODELS CHAPTER 4 Photography through either ETX model requires the addition of the optional #64 T–Adapter (see OPTIONAL ACCESSORIES, page 17). With the #64 T-Adapter attached to the telescope (Fig. 20), through-the-telescope photography is possible with any 35mm camera body with a removable lens. In this way the telescope effectively becomes the lens of the camera. 2 1 7 Fig.22: Example of a format 2 photo.
CHAPTER 5 z Chapter 5: OPTIONAL ACCESSORIES A wide assortment of professional Meade accessories is available for both ETX model telescopes. Meade accessories greatly extend many important applications of the telescope, from low-power, wide-field terrestrial viewing to high-power lunar and planetary observing. The premium quality of these accessories is well suited to the quality of the instrument itself.
z OPTIONAL ACCESSORIES The Meade #126 2x Barlow lens is an achromatic, highperformance, short-focus Barlow Lens, perfectly suited to the low-profile design of both ETX models. Lens surfaces are multicoated for maximum image contrast and light transmission. #825 8 x 25mm Right-Angle Viewfinder: Included as standardequipment on ETX-125EC models, the 8 x 25mm Right-Angle Viewfinder (Fig. 27) permits a comfortable 90° viewing position with 90mm ETX models as well.
z ACCESSORIES OPTIONAL 18 CHAPTER #1244 and #1247 Electric Focusers: 2 5 1 3 4 Fig.30: The #932 45° Erecting Prism shown threaded to the rear cell of an ETX-90EC. (1) #932 45° Erecting Prism; (2) Eyepiece; (3) Knurled lock-ring; (4) Flip-mirror control.
z AND SERVICING Chapter 6: MAINTENANCE General Maintenance Both ETX model telescopes are precision optical instruments designed to yield a lifetime of rewarding applications. Given the care and respect due any precision instrument, the telescopes will rarely require factory servicing or maintenance. Use the following guidelines: 1.
CHAPTER 6 z MAINTENANCE AND SERVICING Unable to see an image through the eyepiece: • Confirm that the lens cover has been removed from the telescope. • Confirm that the flip-mirror control (16, Fig. 1) is in the “up” position if using the eyepiece holder (4, Fig. 1) so that light is directed to the eyepiece (1, Fig. 1).
z TELESCOPE SPECIFICATIONS Specifications: ETX-90EC Astro Telescope Specifications: ETX-125EC Astro Telescope Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain Primary mirror diameter . . . . . . . . . . . . . . . . . . 96mm (3.78”) Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . . . 90mm (3.5”) Focal length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1250mm Focal ratio (photographic speed). . . . . . . . . . . . . . . . . . f/13.
z Appendix A:TRACKING MOTOR SPEED 22 APPENDIX A In the polar mode the Electronic Controller normally tracks objects at the sidereal rate (see Sidereal Rate, page 10). For most observing sessions (once the telescope has been polar aligned and the tracking motor activated), there is little need to change this speed. For objects, like the Moon or a comet, that move at slightly different rates, the Electronic Controller arrow keys (1, Fig.
z CHARTS Appendix B: HELPFUL 23 Latitude Chart for Major Cities of the World Star Locator To aid in the polar alignment procedure (see page 12), latitudes of major cities around the world are listed below. To determine the latitude of an observing site not listed on the chart, locate the city closest to your site. Then follow the procedure below: Following is a list of bright stars with their R.A. and Dec.
APPENDIX C z ALIGNMENT; SETTING CIRCLES Appendix C: PRECISE POLAR Precise Polar Alignment Important note: For almost all astronomical observing requirements, approximate settings of the telescope’s latitude and polar axis are acceptable. Do not allow undue attention to precise polar alignment of the telescope to interfere with your enjoyment of the instrument.
Appendix D: ROADMAPz TO THE STARS The night sky is filled with wonder and intrigue. You too can enjoy exploring the universe simply by following a few pointers on a roadmap to the stars. First, find the Big Dipper, which is part of the constellation Ursa Major. (It is in the center of Fig. 38.) The Big Dipper is usually easy to locate year round in North America due to its proximity to the North Star, Polaris. Extending directly out from the far side of the Big Dipper’s cup is the constellation Orion.
z AND THE UNIVERSE Appendix E: YOU 26 APPENDIX E The distance from the Earth to the Moon Radius = 239,000 miles The distances between the planets The distance from the Earth to the Sun is 93 million miles or 1 Astronomical Unit (AU) Pluto’s elliptical orbitis eccentric and carriesthe planet inside theorbit ofNeptune at itsclosest approachto theSun. The distance between stars The distance from the Sun to the nearest star is about 4.3 light-years, or 25 trillion miles.
MEADE LIMITED WARRANTY Every Meade telescope, spotting scope, and telescope accessory is warranted by Meade Instruments Corporation (“Meade”) to be free of defects in materials and workmanship for a period of ONE YEAR from the date of original purchase in the U.S.A. and Canada. Meade will repair or replace a product, or part thereof, found by Meade to be defective, provided the defective part is returned to Meade, freight-prepaid, with proof of purchase.
Meade Instruments Corporation 6001 OAK CANYON, IRVINE, CALIFORNIA 92618-5200 U.S.A. (949) 451-1450 Ver. 0300 FAX: (949) 451-1460 www.meade.com ETX® is a registered trademark of Meade Instruments Corporation. Part no.
