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82 of 84 people found the following review helpful:
3.0 out of 5 stars
A good **portable** scope: Read This, August 27, 2002
I am the president of a large (300 members) astronomy club in Columbus, Ohio and have looked through thousands of telescopes in my life- including, perhaps, 20 Meade ETX-90s. I find the views of the planets and the moon through the ETX-90 to be consistently good- though not overwhelming. Due to the limited light grasp of this scope, high power views of deep-sky objects (galaxies, star clusters, nebulae) are relatively anemic and uninspiring. However, the scope gives very nice "rich field" (low power) views of the Milky Way and brighter comets.To explain: More than any other factor, it is the aperture of a telescope that matters. In general, aperture dictates portability, cost, resolution (sharpness) and, most importantly, light gathering ability. A telescope is like a bucket for gathering light; the larger the bucket, the more light it gathers. With its 3 and a half inches (90 millimeters) of aperture, the ETX-90 is not a very large bucket. Why is this important? Other than the planets, the moon, and the brightest stars, astronomical objects tend to be very faint. Views through a scope of any size will look nothing like astro-photos. Nebulas, star clusters, and galaxies will, instead, appear to the eye as delicate, cottony, wisps of light. To make these delicate wisps of light more perceptible, most experienced amateur astronomer use scopes with 8 inches of aperture or more. Such a scope will gather 5 times more light than the Meade-ETX 90. What difference does this make? A view of the spectacular M13 globular cluster through an 8 inch scope will reveal dozens of its brightest stars swarming about its "nebulous" center like a swarm of bees. Through the 90 mm of the ETX, one might, under the darkest skies and with a bit of practice, just barely be able to make out that the object is made has stars in it, and is not, in fact, just a fuzzy "nebula". For this reason, I generally steer first time scope buyers to an inexpensive, but larger aperture, "Dobsonian". Those looking for something more portable I steer toward a nice pair of binoculars. On the other hand, this scope is exceptionally portable and convenient to use. It does fit a niche. It is the perfect scope for travel or those quick "gotta' look" moments. It's small size means that it cools off quickly, and can be used almost immediately. With its fixed "Maksutov" design, it never needs collimation (mirror adjustment). I've found the computerized GOTO system relatively easy to use, fairly precise, and programmed with more and fainter objects than one can reasonably expect to see with its small aperture. (Recommendation: learn the names of the brightest 20 or so stars in the sky. You will need them as guide stars to align the scope with.) After a few minutes of setup by an experienced user, sought out objects fall within the low power field of view 90 percent of the time. Finally, some skilled star watchers find delight in "bagging" faint, difficult objects with minimal aperture. It's a source of pride for them to be able to say: "I saw Pluto (as an amost imperceptibly faint dot) in my ETX-90!" NOTE: I have stood next to many first time users of the Meade-ETX and watched them fumble in the dark for hours with the system of computerized menus in the GOTO system that comes with this scope. Learn to use it in the daylight or during the full moon and not while you're cutting into your observing time. In addition, I have one experienced friend whose Meade-ETX 90 simply refused to function properly, but I believe this to be an exception. The 24 millimeter finder is useless for finding anything but guide stars and the planets. It is difficult to align, and is so small that very little can be seen through it. I would recommend getting a dew shield in addition to this scope. The Bottom Line: If your only experience with a telescope is looking through a rickety "department store" refractor, you're liable to be very impressed with this view through a "real scope". If you like to look at the moon, planets, and to surf the star fields of the Milky-way, you will find this scope convenient and enjoyable. However, if you expect glorious views of galaxies, nebulae, and star clusters, either buy a larger aperture scope, or join an astronomy club that owns one.
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by Terence Dickinson
