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Meade ETX, a Telescope for the Masses.

by
Larry Bohlayer
December 1, 1999
Abstract

The Meade ETX-90EC with the Autostar computer could be the only telescope an amateur needs... at the very least, it's a geat first instrument. Here's a first hand usage experience and recommendations on some "optional" accessories that the author deems essential.


Newcomers to astronomy are generally enlightened and careful about spending money on equipment. So, when I am asked "What would be a good telescope?," I ask a few of my own questions about their location, current equipment, and potential pursuits (just look-and-see? deep sky objects?, astrophotography?, etc.) Most often the case is a parent who is just getting interested in skywatching and wants to get a first piece of equipment to share with a growing family and friends. I usually recommend a quality set of binoculars as a starting point, but I can tell that they really have the desire to have a "real" telescope.

Currently, I have a favorite recommendation that I give to these telescope hungry, eager to learn types - the Meade Instrument Company's ETX-90EC. Specifically, the recommendation is the ETX-90EC with three options that, in my usage experience, are essential: the Autostar(tm) #497 computer control paddle, the #825 right-angle viewfinder scope, and the # 883 Deluxe Field Tripod. It may be the only telescope the person ever buys OR NEEDS - so it might as well be worth the approximate $1,000 one would pay for this setup. Besides, this is the most fun, the most motivational, the most educational telescope one can buy.

First, the scope is a compact 90mm (Maksutov-Cassegrain for those of you want the specific optical design) in a 8"x12"x12" package. It is also lightweight - just over 9 lbs. This combination of small size and low weight makes it convenient and easy to transport to an observing location in your yard, or by car to remote location. Of course, the tripod adds more weight (11 lbs.) to the total package to transport. There is also an optional hard case (#774) for the scope and accessories that I suggest for those transporting to remote locations. The optics are superb! Star images are sharp and void of observable abberations. Meade uses BK7 optical glass and all optical surfaces are coated to maximize light transmission.

Combine this fork mounted scope with its battery powered set of dual-axis drives and the Autostar computer control and you have the ingredients for a wonderful experience in observing. Here's why. The Autostar is a handheld controller that has buttons to move the scope's pointing direction and the powerful GOTO button. It is the GOTO button that has given this type of telescope its name: the "GOTO telescope." Once you do a simple three-step alignment of the telescope - a process you are led through with instructions on the two-line LED computer screen - the Autostar brains know the position and tracking requirements for over 14,000 objects you can view by pressing GOTO. This includes the Messier objects, other galaxies, nebulae, and star clusters... plus double stars, variable stars, 50 earth orbiting satellites, 26 asteroids, 15 comets, solar system planets and the Moon.

So, rather than spend 45 minutes in your yard with any other type of telescope and managing to only get the scope into approximate polar alignment and the dew wiped off your star atlas, you could have taken in two star clusters, three nebulae, a couple of planets, and a double star system.

On a recent observing night, I used the ETX/Autostar to showcase the instrument for a few friends. First, I easily carried the scope (already mounted its the tripod that I keep setup in my living room) into the yard. After the tripod legs were extended, I made some minor leg adjustments to set the scope to an eyeballed level. Then I swung the scope by hand in azimuth to point roughly north with the tube level - what the ETX instructions call the HOME position. I pushed the power switch to "on" and the red LEDs on the handheld computer came to life and in a moment a warning message about looking at the sun was streaming across the display. This message was acknowledged by pressing the "5" key. The Autostar computer continued with an instruction to press the "?" key for a detailed overview of the Autostar functions. I skipped the "?" and pressed the Enter key and was asked for the current date, then the time, and the daylight savings status. (As an aside you should know that the first time I had used the Autostar, I was asked for and entered my geographic location information which is remembered by Autostar.) I next chose "Easy" alignment from the display prompt after which the instruction told how to put the scope in the HOME postion (which I had already done earlier).

Then the magic began. The internal motors begain slewing the scope and the display flashed that I should "Center Altair" (a bright star in the constellation Aquila). I didn't need to know which star was Altair since the finder scope showed it as the only bright star nearby. Using the arrow keys on the Autostar control a few pushes brought Altair into the center of the finder then the main scope. Pressing "Enter" led to the motors moving the scope near another bright star with the display asking me to "Center Alioth." Again, I didn't need to know the name of this bright star and proceeded with the centering using the slewing motor controls on the computer paddle. I pressed "Enter" and was rewarded with the display response of "Alignment Successful." The motors also began to incrementally drive the scope to track the star. Total time elapsed from putting the tripod in the ground to alignment: 5 minutes.

The Autostar computer display now showed the top tier in its database, "Select Object," under which was a scrollable list of OBJECT levels: "Solar System", "Constellation", "Deep Sky", "Star", "Satellite", "User Object", "Landmarks", and "Identify." I picked "Deep Sky, Named Objects, Crab Nebula" and the computer correctly responded that that nebula was below the horizon. So I picked the Helix Nebula from the scrolled list and pressed the GOTO button. After 30 seconds of slewing, the motors slowed to tracking speed and the computer control beeped to indicate arrival. I looked through the main scope using the provided 26mm Super Plossl (48X) eyepiece and voila! there it was, just slightly high in the field of view. Pressing the scroll keys on the Autostar told me further information about the Helix Nebula including its designation as NGC 7293, that it is a planetary nebula, that it is positionally at RA 22:29.6 and Dec. -20 deg. 48 min., that it is in the constellation Aquarius, has a magnitude of 6.5, and is roughly 450 light years away. Now this is fun and informational for the observer - expecially a beginner!

The tracking kept up with the nebula's apparent motion (the motors were driving both axes since the scope was in alt-azimuth position-and an imprecise one at that!). A parade of other observers took their turns at the eyepiece and we were all excited about testing the ETX's GOTO feature on another object. Next we tried Object -> Solar System ->Jupiter. Within a few seconds, the scope had slewed and began tracking Jupiter not too high up in the southeastern sky. Again, the scope was just slightly off dead center in targeting Jupiter, but a few button presses on the slewing motor buttons brought it centered in the field. Scrollable database information on Jupiter included its current position, magnitude, rise and set time, mass, apparent diameter, actual diameter, distance from earth, length of day, orbital period, surface gravity, temperature range, number of moons, and more.

By this time we were comfortable with the Autostar's relatively intuitive interface controls and had discovered the selection choice of "Guided Tour." Making this selection gave us a list of Jupiter, Saturn, Messier 32, the Andromeda Galaxy, the Double Cluster, Messier 13, Messier 92, the Wild Duck Cluster,... well you get the idea by now. Pressing the GOTO button was a task I invited each of the visiting astronomers to do and we were delighted to confirm the Autostar's finding the object. But let me just tell you that the computer also provides information on the spot from a complete glossary of astronomical terms. You can even select the Events list to see calculated sunrise/sunset, moonrise/moonset, the next full moon date/time, etc. - answers to questions your friends are likely to ask while you stand out under the stars.

While the ETX was not meant to be a deep sky astrophotographer's scope, it serves that enormously large interest group that wants to have a quality optical instrument for observing and taking simple astrophotographs. The great bonus with this scope is that it has a built-in teacher and guide. Yes, you can still learn the shortcuts to finding all those faint objects and develop a mental familiarity with a map of the sky, but why not have a GOTO guide that you can rely on to get you there! Why not have a scope that can find and show you objects you would never consider seeking out? Why not have a scope that you keep ready for quickie observing session that will always be productive. The era of closeted, dust gathering telescopes is over with this instruments.

Oh, the ETX is also a great scope to set at your window to take in terrestrial views. Get the optional #932 Erecting Prism for the eyepiece end that makes the view through the scope correct in its right/left view. (The normal astronomical view of switched left/right does not pose a discomfort, but when viewing terrestrial objects, is may be desirable in knowing the correct way a bird was facing, which side of the building was in the scene, etc.)

Why do I claim the necessity of getting the "optional" right angle finderscope and the Deluxe Field Tripod? The factory delivered ETX-90EC has a "straight through" finder scope that is mounted so close to the main tube that it is virtually impossible to get your head in to see through - especially when the telescope is aimed above 10 degrees altitude. The right angle finderscope solves the problem allowing easy head positioning - just like the main scope's right angle viewing system.

While the ETX is readily usable sitting on a table or other surface, practicality calls for a really sturdy, stable platform that the tripod provides. A special mounting head on the Deluxe Field Tripod mates quickly with the scope. It is lightweight and extremely rigid when set up. You'll only be thankful for having one under your ETX.

There are even more capabilities and accessories than mentioned here. For instance there is a direct PC to ETX connection that coupled with Meade's SkyChart Astro Software allows the scope to be controlled from your computer keyboard. There is also the luxury of an electric focuser. Frankly this latter item I believe is unnecessary for astronomical viewing, but would be a splendid luxury for terrestrial viewing where a variey of focus distances are in play.

----------About the author----------

Larry Bohlayer is the founder and president of Celestial Products, Inc., a publisher and distributor of astronomical resources including the Meade ETX-90EC.

----------More ETX information----------

You can request literature and pricing information about the ETX/Autostar system and other astronomical resources from Celestial Products by calling 800-235-3783 or sending e-mail to info@celestialproducts.com



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