Meade ETX-80AT-TC


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Brand and Model:Meade ETX-80AT-TC
Price ($USD):279.00
Type:Achromatic Refractor
Attributes: checked Go-To un-checked PEC
Aperture:80mm
f Ratio:f/5
Focal Length:400
Finder:
Electric Power:battery
Mount:alt-az
Tripod:
Weight (lbs):
Dimensions (w/h/d):
Description:Wide field refractor with Meade's ETX 494 Autostar go-to system.

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Meade ETX-80AT-TC
I didn’t get this telescope for myself, but for my 8 year old grandnephew who foolishly spent $50 – the total of cash gifts for his birthday – on the typical junky department store telescope. After considerable research, I thought this telescope would expand any natural curiosity that might be there, while the just purchased, poorly constructed department store telescope would probably kill it. It’s the first telescope I bought in over twenty years, although I’ve pecked away at eyepieces from time to time.

Since everybody talks about the views of the moon, Jupiter, Saturn, etc., I’ll let others discuss the usual agenda later on and concentrate instead on how some of the data is arranged in AutoStar #494 (the data base/tracking system) because I haven’t come across an extensive and reasonable critique of this part of the package.

As the ETX 80AT seems to be an upgrade of the ETX 70AT which was, in turn, an upgrade of the ETX 60AT (I think!), you will find important information by reading those reviews. In the current ETX series, the 80mm with a 400mm focal length is the only one that can be considered a rich field telescope (RFT); the others (90mm, 105mm, and 125mm) have three to five times the focal length of the 80mm. Looking at previous reviews of the predecessors and current stablemates in the series, I agree with the general consensus that (1) the tracking system is pretty good, (2) the battery life is overstated, and (3) the focusing knob is awkward in some situations.

The ETX 80 comes with two eyepieces: 26mm and 9.7mm Super Plossls. Fortunately I also have the Televue (“TV”) 32mm Plossl: 12.5X with a very bright, very crisp image in a four degree field-of-view. It delivers virtually everything you could ask for from an RFT in this price range. The view with the TV 32mm Plossl in this telescope is something you simply have to see to believe. You'll get spoiled right away!

Now I can't say the difference between the TV 32mm eyepiece and the supplied Meade 26mm eyepiece is the difference between night and day. But the image was clearly preferable in the TV 32mm Plossl. I'm pretty sure I would have been almost as enthusiastic with the 26mm, unless I had the 32mm for comparison.

I expect that the Meade 32mm Super Plossl will provide a view similar to the TV 32mm Plossl, although substituting the 32mm for the 26mm would probably edge the street price up a bit. Plus the TV eyepiece has a little longer eye relief, which I appreciate since I wear glasses.

But the nice, sharp, contrasty image at the lowest practical powers has nowhere to go but down at higher magnifications, and it does, but not too much until over 50X. The usual violet fringing with such achromats, hardly noticeable at low powers, becomes more obvious at increasingly higher powers, again not too bad until over 50X. (Other observers with different tolerance levels will undoubtedly have different opinions and, if the fringing bothers you, try a violet reduction filter.)

There is a built-in 2X Barlow that you can access simply by flipping a switch. It’s obviously an attractive marketing gimmick, but very awkward to use in practice because, with the same eyepiece in place, you have to turn the focusing knob about 50 to 60 times in a counterclockwise direction before the image snaps back into focus, and vice versa when you flip it back. I found it much easier to insert my TV 2.5X Powermate, which maintains focus with the same eyepiece with just one to two turns of the focus knob. So don’t get rid of your Barlow or your Powermate, if you have one. (Hint: so it is a good idea to use eyepieces that are parfocal, as the supplied 26mm and 9.7mm eyepieces are, and so are the other eyepieces in this Meade line from 6.4mm to 32mm.)

At the moment (May 2006) there is no dewcap for the ETX 80, although there should be one in a few months. And I have yet to get the central lock to work on the tripod. The tube attached to the objective lens in my telescope has come loose, but this was easily fixed with some superglue.

There has been an infrequent knock here and there on the data base of the AutoStar #494 Computer System. This system is where the raw data and computer processing are stored on a microchip (I think!). Reluctantly, I’m afraid that I’m going to add a few more that I’m rather surprised haven’t been mentioned so far:

Double Stars:

There is a generally agreed upon pecking order in the naming of double stars: Bayer system first (gamma Andromedae), Flamsteed system second (61 Cygni). If the star has a well known Arabic name, that name is frequently substituted for its Bayer designation: gamma Andromedae is sometimes referred to as Almach (or Almaak). Then, if there are no Bayer or Flamsteed designations, the catalogue number of a given discoverer is in third place: one of the Struves, one of the Herschels, Burnham, etc.

The organization on the data base of the AutoStar #494 lists the stars in alphabetical order with Arabic names - several not commonly known - merged in with the Greek letters in the Bayer system. If there are no Bayer or Arabic name tags, the default name is an SAO number (= abbreviation for “Smithsonian Astrophysical Observatory”) for the primary, a designation for double stars not commonly used in observation handbooks. Most of you with some experience won’t recognize the SAO numbers for the doubles in the data base, but would have if the Flamsteed designation had been used.

And how many of you know which double star Achird is? This is the rarely used Arabic name (meaning “girdle”) for eta Cassiopeiae, a well known, easily resolved, and one of the more colorful double stars. On the AutoStar #494 double star list, this appears alphabetically under Achird, but NOT under its far more common name of eta Cassiopeiae.

What do you think your chances are of finding eta Cassiopeiae on this list if you weren't aware of the match?

(This something that could be straightened out with an expanded instruction manual, by adding another appendix providing equivalent names.)

An observer trying to determine whether he/she can resolve a double star likes to have the magnitudes of the brighter and secondary components, accompanied by the separation and position angle. These minimum parameters appear consistently in the guidebooks and various double star lists. The AutoStar #494 gives the magnitude of the brighter component, then the separation of the components, and that’s all. No position angle, and no magnitude of the secondary (and the magnitudes of several secondaries in the data base are way too faint to be seen in this telescope).

Meade does supply other information, some of which you would not normally have available: Bayer designation (if the star is on the list under its Arabic name), its SAO number, distance, and spectral class (primary only). There's also a display of the coordinates which AutoStar needs to do the locating and tracking. But, outside of the separation distance, there’s virtually no information on the secondary.

Dozens of pretty, contrasty double stars - readily located in the auto tracking mode, on most double star lists, and easily resolved using this telescope - have been overlooked, and that’s rather sad. To Meade’s credit, there is a way each user can add interesting objects to the data base. All in all, however, the list of double stars on AutoStar #494 leaves an awful lot to be desired. Whoever put this list together ignored many of the more popular and colorful double stars known by most amateurs with a little experience, and Autostar would have made them easily observable like never before.

Clusters:

There are two types of clusters: open (or galactic) clusters and globular clusters. The first generally have anywhere from a few dozen to a thousand or more stars in them. The globular clusters have from tens of thousands to hundreds of thousands of stars. Most of the open clusters are at least partially resolvable with a small telescope - many of them almost completely so - while the Meade ETX 80 can begin to resolve only a handful of the closest globular clusters.

Both types of cluster are merged on the same list in the database (under “clusters”), although most amateurs would probably agree that the two types of clusters look so different in a small telescope that they ought to appear on separate lists, and they usually do.

Variable Stars:

Again, we like to know what type of variable it is: cepheid, eclipsing, long term, irregular, semi-regular, etc. Then what is the usual magnitude range, and what is the period? Only the name and maximum magnitude appear in the AutoStar #494 data base, although for some of the more famous variables there is a written description that fills in some of the details. But not even the “bare bones” parameters are given for most of the variables. On the other hand, there are the usual generic data: SAO number, coordinates, spectral class, and distance.

This time the Bayer names are given priority in the listing (compared to Arabic names in the double star list). So if you’re looking for Algol, you won’t find it unless you look under beta Persei on the list. And you’ve expected to know that Mira is omicron Ceti. While a more experienced observer will probably be able to make the translation, this is expecting an awful lot from a novice.

Other Quibbles:

Did you know that, according to AutoStar #494, the luminosity classifications of Betelgeuse and Antares are “M1V”? The “V” at the end means it’s a star on the “main sequence” of the Hertzsprung-Russell diagram (like the sun is). This designation means that Betelgeuse and Antares are red dwarfs, rather than the red supergiants they really are! The “V” should be an “I”, with “I” indicating supergiant. The difference between a “V” and an “I” in the luminosity classification of these two stars is the difference of several thousand times in luminosity and several hundred times in size.

There is no way a competent astronomer would make such mistakes in any description of these two bright, familiar stars.

By the way, did you also know that Betelgeuse is "possibly the largest star known today" acording to the information on the variable star list? Hmm…I read over fifty years ago that mu Cephei - Herschel’s “Garnet Star” - held that distinction (and, despite what the authors of AutoStar #494 say, still does among the naked eye stars). And I almost forgot: even though mu Cephei is thought to be over two billion miles in diameter (larger than the orbit of Saturn) it’s on Autostar as - you guessed it! - “M2V”, a red dwarf!

In general, the accepted distances to the stars these days are the ones determined by the Hipparcos satellite in the 1990s. When you see the distances listed for some of these stars in the data base, you ask “Now where did that come from?” For example, the distance to Deneb is given as 545.4 light years in its write-up as a variable (?) star. But the short written description in the same section also estimates its distance as 1600 light years. (Hipparcos measurements suggest a distance of over 3,000 light years to Deneb, but are not considered reliable in that range; something in the neighborhood of 1600 light years is generally accepted.)

These outrageous errors would lead one to question whether there was any editing of the original data. Frankly, I have never seen this many gross errors in anything being marketed to the public, and I’ve been reading astronomy books for over 50 years. (And, believe me, these are just a FEW examples of numerous sloppy errors in the descriptions!)

On the positive side, when you set up the telescope the first time, you’re asked to enter your zip code. This (apparently) determines your geographic location and predicts sunrise and sunset, moonrise and moonset, etc., for your location. The sunrise/sunset times on the AutoStar #494 for my zip code differ by no more than two minutes from the times predicted on the Weather Channel internet site using the same zip code.

In summary, in the ETX 80AT Meade has developed a smoothly operating and highly accurate tracking system matched synergetically with fine optics, but certain parts of the data base obviously need to be “debugged” and/or “conventionalized”.

What rating to give?

I’m NOT rating the data base of the AutoStar #494 in this section on telescopes (fortunately!), although you should be aware of the quirky parts in the data base before you make the purchase. I’ll give the telescope itself a “9” for the optics (what I'm most interested in) and a "9" overall, but the marvelous view with the TV 32mm Plossl probably pushed both up a step or two. It does at low magnifications all I could ask for at the price - in fact, even more - and a top notch 30 to 32mm eyepiece seems to coax out everything that’s there in this RFT. And, quite honestly, the optical performance at all magnifications was much better than I expected in a telescope with this focal length and modest price.

I’m sure my eight year old grandnephew will have lots of fun with it. As a matter of fact, so will I.

Overall Rating: 9
Optics:9 Mount:8 Ease of Use:8 Value:9
Weight: 5 (Veritable Vote)
Date:
By: mrf
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=506772


Meade ETX-80AT-TC
I got the etx 80 and i must say it is superb. (as long as you can point out the north star) i wouldnt recomend using the compass as it is a little out (15 degrees!!!) so align it using the north star. to do this i looked through the eyepiece centerd polaris then put the Dec to 0. pretty simple only took 1 minute too. mine came with a red led torch which was a bonus as i could use it to look at things and once i turned it off it took about 2-3 seconds for my eyes to adjust instead of 15-20 minutes. i was also impreesed with the quality of the eyepieces that came with it. i think that it would have been beter with a 4mm and a 16mm and a 24mm. all in all a good buy.

Overall Rating: 9
Optics:10 Mount:9 Ease of Use:9 Value:7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.189.239)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=570732

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