Meade ETX90EC Telescope w/ UHTC, Autostar Controller (497) and Tripod (884)

Images through the ETX90EC are absolutely textbook perfect. The excellent optical quality produces some wonderful views of brighter sky objects, such as the Moon and naked-eye planets. Meade's recently introduced UHTC optical coatings further strengthen optical performance by enhancing image contrast. Given the amazing low price for what you get, the ETX90EC is a great triumph in low-cost, mass-production optical fabrication techniques.

The computer-driven hand controller makes it easy to find 14,000 celestial objects.

As good as the optical assembly is, the finderscope leaves something to be desired. I find it difficult, if not impossible to look through because of how closely it is mounted to the tube of the telescope. The problem only gets worse as the telescope raises in altitude, causing my nose to scrunch up against the eyepiece. I would recommend augmenting the finder with a small one-power aiming device, such Orion Telescope's EZ Finder II Reflex Sight. Another drawback is the focusing. Although the focuser's movement is smooth, the small, aluminum knob is very difficult to grasp when looking through the eyepiece.

The tube assembly comes mounted on a miniaturized, clock-driven, fork equatorial mount made mostly from molded plastic. The DC-powered clock drive runs for more than 20 hours on eight common AA-size batteries. The clock drive tracks the sky quite accurately after it has been properly initialized.

Consumers should note, however, that since the tube is longer than the fork arms, the telescope cannot swing all the way through the mount. This could limit the telescope's ability to look low in the sky, depending on how and where you have it set up. What that point is exactly will depend on the angle at which the ETX is tilted for polar alignment, but it worsens as you head south. I also feel that the plastic fork mounting is just barely solid enough to support the weight of the telescope. It is certainly not strong enough to hold both it and a camera.

Overall, despite the weaknesses mentioned above, the ETX90EC is a well-made instrument and has an amazingly low price. Computer tracking and slewing coupled with outstanding optics in such a compact package would have been unimaginable just a few years ago. Yet, here it is. --Phil Harrington, author of Star Ware

Pros:

• Outstanding optics
• Compact size
• Amazing value for the money
• Accurate computer control and tracking

• Poor finderscope
• Weak plastic mounting
• Focusing knob very close to eyepiece
• Small aperture only suitable for the brightest sky targets

The UHTC Difference

Each time light encounters a mirror (above) or lens (below), some light is lost. In the case of a lens, light is lost at both the entrance to and exit from the lens. UHTC dramatically decreases this light loss.

Ultra-High Transmission coatings (UHTC), recently developed at the Meade Irvine coatings facility, however, have permitted the vacuum-deposition of a series of exotic optical coatings precisely tuned to optimize the visual, photographic, and CCD imaging performance of Meade telescopes. This telescope includes primary and secondary mirrors coated with aluminum enhanced with a complex stack of multi-layer coatings of titanium dioxide and silicon dioxide. The thickness of each coating layer is precisely controlled to within 1% of optimal thickness. The result is a dramatic increase in mirror reflectivity across the entire visible spectrum; at the important hydrogen-alpha wavelength of 656nm. - the predominant wavelength of emission nebulae -- reflectivity is increased from 89% to over 97%.

This telescope presents dramatically brighter images on the full range of celestial objects — from emission and planetary nebulae such as M8, M20, and M57 to star clusters and galaxies such as M3, M13, and M101. Observations of the Moon and planets, since they are observed in reflected (white) sunlight, benefit in image brightness from the full spectrum of increased transmission.

And more
The ETX-90EC also includes high-torque DC motors on both telescope axes, permitting electronic operation from the handheld controller. This pushbutton electronic controller has four dual-axis drive speeds: slow, 8x for image centering at high power; medium, 32x for image centering at lower power or for pushbutton tracking in altazimuth mode; moderate, 0.75 degrees per second for image centering in the viewfinder or for terrestrial tracking; and fast, 5 degrees per second for fast scanning across the sky.

The Meade ETX-90EC is specially designed to be portable and used in the field. It offers cordless operation, allowing you to use the telescope's dual-axis drive system for more than 40 hours on eight AA batteries. At approximately 8 pounds, and 15 inches in length, it packs a lot of power into a compact unit.

The ETX-90EC uses a 90mm Maksutov-Cassegrain optical design. Meade also uses EMC super-multicoatings on all optical surfaces to maximize light transmission through the corrector lens and reflectance from the primary and secondary mirrors. The flip-mirror system allows for 90-degree observation of land and sky objects, straight-through observation using the optional 45-degree erecting prism, or photo-ready imaging using the optional T-adapter and your own 35mm camera.

The Nuts and Bolts

1. Eyepiece 2. Viewfinder 3. Eyepiece Holder Thumbscrew - Tightens the eyepiece in place. 4. 90 Eyepiece Holder - Holds the eyepiece upright for easy viewing. 5. Optical Tube - The main optical component that gathers the light from distant objects and brings this light to a focus for examination with the eyepiece. 6. Vertical Lock - Controls the manual vertical movement of the telescope. 7. Fork Arms - Hold the optical tube in place. 8. Focus Knob - Moves the telescope's optical tube in a finely-controlled motion to achieve precise image focus. 9. Horizontal Lock - Controls the manual horizontal rotation of the telescope. 10. Computer Control Panel A. ON/OFF Switch. B. Auxiliary Ports - Provide connection for current and future Meade accessories. C. Handbox (HBX) Port - for the Electronic Controller or the optional Autostar handbox. D. The 12v connector, designed to accept an external power supply such as the optional AC Adapter or Power Cord. E. LED power indicator light. 11. Base Housing - Supports the telescope for placement on a flat, level surface, such as a tabletop or optional tripod. 12. Holes for Optional Tripod - See your tripod's instruction sheet for mounting information. 13. Right Ascension (R.A.) Setting Circle. 14. Flip-Mirror and Flip-Mirror Control Knobs - ETX telescopes include an internal mirror. With the flipmirror control in the "up" position, light is diverted to the eyepiece. With the flipmirror control in the "down" position, as shown in Fig. 2b, light proceeds straight out the photo port for photography. 15. Photo Port - Attach any 35mm camera with a removable lens to this port using an optional adapter. 16. Declination Setting Circle (on left fork arm). 17. Viewfinder Alignment Screws - adjust these screws to align the viewfinder. 18. Viewfinder Alignment Bracket. 19. Dust Cap 20. Battery Compartment (not shown, underneath base).