ETX FREQUENTLY ASKED QUESTIONS (FAQ)
This ETX FAQ was prepared by Dominique Rodriguez. It is presented here with the permission of the author. Please address all comments, corrections, and additions to Dominique. Dominique's email address was changed at the end of June 1997; I will post the new one as soon as I receive it.
============================================================================== ETX Frequently Asked Questions List (FAQ) Dominique RODRIGUEZ firstname.lastname@example.org v0.alpha_3, 23 June 1997 ---------------------------------------------------------------------------- Answers to Frequently Asked Questions about Meade ETX telescope ---------------------------------------------------------------------------- 1. Introduction * 1.1 Overview 2. Miscellaneous Questions * 2.1 I'm a novice, and I have some questions. Where should I start? * 2.2 What Usenet Newsgroups are there for the ETX? * 2.3 Are there any good WWW links for ETX stuff? * 2.4 What are good places to buy ETX's and accessories? * 2.5 When is the next Meade coming out? Should I wait? * 2.6 What are the specifications of the ETX? * 2.7 Can the unit be attached to a standard camera tripod? * 2.8 How does the ETX compare to the TeleVue Ranger? * 2.9 How does the ETX compare to other instruments? * 2.10 Do I need a perfectly level surface for doing the polar alignment? * 2.11 Can the ETX be a first scope for a novice? * 2.12 Meade advertises a resolution of 1.3", is it true? 3. What kind of accessories can I used on my ETX? * 3.1 Which tripod can I used? * 3.2 Which cases/bags can I used? * 3.3 Which eyepieces can I used? * 3.4 Which barlow lenses can I used? * 3.5 One told me that using a Barlow on the ETX will give a too dark image? 4. What possible mechanical modifications/enhancements can I make on my ETX? * 4.1 Can I computerized the ETX? (goto function) 5. Contributors ---------------------------------------------------------------------------- 1. Introduction This FAQ is maintained by Dominique RODRIGUEZ (email@example.com) 1.1. Overview The purpose of this FAQ is to provide answers to commonly asked questions about the Meade ETX Telescope. This list contains information which has not necessarily been verified, and is not guaranteed to be correct. It has been compiled from various postings in the newsgroups sci.astro.amateur, as well as other sources. 2. Miscellaneous Questions * 2.1 I'm a novice, and I have some questions. Where should I start? Having access to Internet, start there. There are innumerable WWW sites on the subject of astronomy and advice to the beginners. Also try local astronomy stores - they will have information about local clubs, meetings, star parties, seminars, observatories and planetariums. * 2.2 What Usenet Newsgroups are there for the ETX? You can find info on sci.astro.amateur, there is also a mailing list dedicated to the ETX, for subscribing goto: o http://metxug.elendil.com/newsltr/newsindx.html * 2.3 Are there any good WWW links for ETX stuff? Try http://www.weasner.com/etx/ which is a good starting point. It has links to many other pages of interest. * 2.4 What are good places to buy ETX's and accessories? Check at the authorized Meade dealer of your area: o http://www.meade.com/dealers.d/dlrtop.html Try subscribing to ASTROMART or visit their site: o http://www.astromart.com/ * 2.5 When is the next Meade coming out? Should I wait? They will not tell. Don't wait. ETX is a great scope that will give you years of good service. The technology did not change much since Newton, and his telescope would be quite useful today. It makes more sense to go for a better or bigger scope than to wait for next design and waste all this observing time. Remember that ETX offers foremost portability and ease of set up. That will make it more likely for you and your family to use it. Bigger and more complex scope will give you better image, but the pain of taking it out and setting it up will make you turn on the TV instead. I know some people that have both and their ETX time is few times that of the bigger scope time. Don't wait! I waited 20 years too long. * 2.6 What are the specifications of the ETX? Optical design.........................................Maksutov-Cassegrain Clear aperture.................................................90mm (3.5") Focal length................................................1250mm (48.6") Focal ratio (photographic speed)....................................f/13.8 Near focus....................................................3.5m (11.5') Resolving power...............................................1.3 arc secs Super Multi-coatings..............................................standard Limiting visual stellar magnitude.....................................11.7 Maximum practical visual power........................................325x Optical tube dimensions.............10.4cm dia. x 27.9cm long (4.1" x 11") Secondary mirror obstruction...........................27.9mm (1.1"); 9.6% Telescope mounting..................................fork type; double tine RA drive motor................................................4.5-volts DC Hemispheres of operation.......................north and south; switchable Slow-motion controls..................................manual; R.A. and Dec Bearings...............................................R.A. and Dec: Nylon Materials: Tube body................................................aluminum Mounting........................high-impact ABS, steel reinforced Primary mirror......................................Pyrex. glass Correcting lens........................BK7 optical glass, Grade-A Telescope dimensions...................38cm x 18cm x 22 cm (15" x 7" x 9") Telescope (incl. tripod) net weight........................4.2kg (9.2 lbs) Telescope shipping weight.................................5.6kg (12.4 lbs) * 2.7 Can the unit be attached to a standard camera tripod? Yes, technically possible but not advisable. The scope weighs about 5 kg and if used in equatorial position it puts serious strain on most tripods. It may make it unstable and you can ruin your ETX. A quality of mounting can be measured by how long does it take to stabilize after touching it. Most cheap tripods will take 5 to 10 seconds which makes them in my eyes nearly unusable. Every time you adjust something or a slight breezes will make them swivel and shake. I have seem mounts that shake when one thumps the ground next to the tripod. Notice that almost all photo tripods come to a narrow point someplace in their set up. If this point is plastic, the tripod is not usable. The stronger that point the better. This is why tripods made for VIDEO applications are much better, but often cost more than the whole ETX. They are designed for heavy cameras and no shakes, but minimal adjustability. Notice that astro tripods are not connected to a single point like photo tripods, but rather to a large table, which makes them much more stable. Notice that the scopes are suspended in such a way that the center of gravity is over the middle of the tripod. This is almost not attainable in photo tripods in the equatorial set up. * 2.8 How does the ETX compare to the TeleVue Ranger? Following are all the articles I found on sci.astro.amateur for last year (1996) concerning this topic. - from (http://www.mich.com/~bhalbroo/startimes6_96.html) Some of you may be thinking that, while the ETX vs. Questar test makes sense, comparing the ETX with the TeleVue Ranger is like comparing apples to oranges. The Ranger is a short focal length refractor particularly well suited to stunning wide field views of extended deep-sky objects. In contrast, the ETX is an f/13.8 Maksutov-Cassegrain with nearly three times the Ranger's focal length--definitely not a low power, wide field viewing instrument. - from Tim Gillespie (firstname.lastname@example.org) Clayton E. Cramer wrote: [edited] > I could only compare them in daylight. The ETX had a very > unpleasant black spot with the low powered eyepiece that was in it. ^^^^^ ^^^^ This is really an unfair comparison. The black spot was due to two factors: 1) A low powered eyepiece produced a rather large exit pupil and 2) Being daytime, your pupil was contracted, thus being unable to accept the large exit pupil. This secondary shadow would not be apparent at night. I find that the easiest way to select a purchase is to compare features side-by-side. So, here goes. Some of these criteria are objective data, others are subjective and reflect my opinion (your mileage may vary): ETX Ranger --- ------ optical performance: very good (though obstructed) excellent (unobstructed) focal length: 1250mm 480mm focal ratio: 13.8 6.8 aperture: 90mm 70mm central obstruction: 27.9 mm diameter none light gathering area: 73.2cm^2 (9^2 - 2.79^2) 49cm^2 mount: passable equatorial none price: $500 - $600 $1000 (?) fit and finish: fair excellent portability: excellent excellent ease of use: excellent fair (no mount) D Rodriguez Here: the price of the Ranger is wrong, Tim send an aknoledgement in a latter mail saying he quoted the price of the Pronto, the Ranger is $600. - from Tim Gillespie (email@example.com) Scott Kroeger wrote: > Also the ETX doesn't gather quite as much light as it's aperture > suggests. The ETX has two mirrors (which I'll guess are about 94% Good point Scott. However, I believe that both mirrors are coated for 96% reflectivity, not 94%. This equates to a reflective transmission loss of 7.84%, bringing the ETXs effective light gathering area closer to 67.5 cm^2. > reflective, does anybody thing Meade is doing better than this) and a > deeply curved corrector which will tilt the AR coatings off normal for > the incident beam over a substantial fraction of the aperture. AR > coatings work best on-axis (where you can't see them). I have seen a > little off-axis reflection from a head-on view of the ETX front end, so > some light is coming back off the corrector. I wouldn't hazard even a > wild guess as to how much. > > If we presume the transmission losses are equivalent for the Ranger > objective and ETX corrector, we can simply take the 73.2cm^2 x 0.94 x > 0.94 and get 64.7cm^2. Quite true, recall that the Ranger is an air-spaced doublet, giving four air-to-glass interfaces which probably about offsets the effects due to the deep curvature of the corrector on the ETX. Lets split the difference, and say about 65cm^2 effective area. That is about a 33% greater light grasp for the ETX. > Given the inevitable shift of energy from the airy disc to the > diffraction rings in the ETX (because of the obstruction) I think it's > small light gathering gain might be offset by the somewhat more diffuse > star images which lower surface brightness and can cause dim stars to > fall below the eye's detection threshold. For diffuse objects the ETX > will give brighter images, but for dim clusters, globular resolving and > planetary views I'd expect a close race (perhaps dominated by the > difference in eyepieces needed to get the same FOV). Couldn't have said it better. The ETXs aperture DIAMETER is about 29% greater than the Ranger, but its aperture obstruction is about 31% (by diameter, NOT area) so, if we make the EXTREMELY tenuous assumption that both relationships (aperture to resolution, and obstruction percentage to resolution) are essentially linear, the effects more or less cancel each other out. In my experience, the Ranger gives superb lunar and planetary images. I have only looked through the ETX once, and found its images excellent as well. A side-by-side comparison would be interesting. I also find it interesting that the ETX is more suited to high power viewing than the Ranger due to its higher f-ratio and longer focal length. For example, a 4.8mm eyepeice in the ETX gives a magnification of 260x. To get the same magnification on the Ranger, you would need either a 1.8mm eyepiece (with the attendant poor eye relief) or a 2.5x barlow (with its attendant transmission loss, potentially reflective extra surfaces and other aberrations) > But there is that big difference in price and the ETX's EQ mount. Those > are two pretty important distinctions in my book. I guess the difference is whether you are interested in performance or quality. IMO, the ETX equals, and in deep space performance, exceeds the Ranger in performance, but lacks the feel of quality that all TeleVue products possess. - from Wil Milan (firstname.lastname@example.org) I've compared the ETX and the Ranger directly. After doing so, I bought the Ranger. The ETX is a very nice small scope, but after a few weeks of use I've found the Ranger nothing short of amazing. With a mild Orion Skyglow filter I can easily see the Veil nebula, the North American nebula, and other objects which many find elusive on much larger scopes. I've also used it at high power and was amazed that the image did not break down even at 288x (100x per inch!). Though I originally bought the Ranger for use as a guide scope on a couple of larger scopes, I've found it so capable that it is now my standard "quickie" scope for short sessions and for traveling. Based on my experience I would not hesitate to recommend the Ranger over the ETX. That's not to take away from the ETX, which I do think is a very nice scope, but the Ranger is a true jewel. - from Wil Milan ("Wil Milan"@ccm.ch.intel.com) ... [stuff deleted] ... You also left out of your comparison that the mount which comes with the ETX is a small tabletop tripod, which means one has to have a table or other flat platform on which to set it. Unless one has already broght along a solid table for some other reason, bringing a tripod for the Ranger is a lot less trouble than bringing a table for the ETX. ... [stuff deleted] ... - from Jeffrey R. Hapeman (email@example.com) Well, Jay, with the recent price inreases in the ETX, the spotter version is very close in price to the Ranger (and the astro more expensive). I have done side-by-side comparisons of the Ranger and the ETX, and MUCH TO MY SURPRISE, the Ranger won out at all magnifications I expected the extra aperture of the Meade to win out). To make the comparisons fair, I used the same Meade series 4000 eyepieces in each scope (but obviously not the same focal lengths--that would result in unequal magnifications). When I tried to figure it out, I figured it probably had to do with all of the following: 1)amount of unobstucted aperture, 2) transmission of the glass (BK-7 for the ETX corrector, and I believe BK-7 for the one element of the Ranger/Pronto doublet and of course, ED for the other), 3) transmission of the coatings, and 5) the reflectivity % of the two mirrors in the ETX (probably 86-89%). Overall, with a little calculation, it's easily seen how the Ranger could have won. As for resolution--well that's easy to figure out. The Ranger won hands down, very easily, using a standard resolution chart form Leica--no central obstruction in the Ranger. Finally--meow back--there isn't much plastic in the Ranger (except for the cap and a set screw or two), whereas the Meade is at least 1/2 plastic. So, to me, the question is, which scope is a better long-term value. I'd vote Ranger any day, even though I really like the Meade otherwise--I have nothing against them and own many of their products. Finally, the Ranger beat out a Questar--probably for the same reasons. So now I'll reveal a bias--I sold my Questar as a result and bought a Pronto (plus some great eyepieces and pocket change, to boot). I'm now preparing for the flames of the Questar owners (and I too have a hacksaw, but I never used it on my Questar). - from firstname.lastname@example.org (Harvey Mace) I want to buy one of these scopes and hoped to find some information on the internet to help me make the choice, but so far I have found contradictory reports, eg. in the review in Star Times (http://www.mich.com/~bhalbroo/startimes6_96.html) the ETX gave better resolution on a chart test, while a recent posting in this group stated the Ranger was clearly better in this respect, etc. [stuff deleted] - from Jeffrey R. Hapeman (email@example.com) Harvey: I totally agree with Jim's advice in every respect. See my post in reply to Jay from earlier tonight. I know Bill Ferris, whose article on the Ranger/ETX/Questar you referred to earlier. In fact, when he left Eagle Optics, I took his place (I had to fund my hobby somehow, and I was always in there buying something). Bill told me that other ETX's (such as the one I looked through at Eagle, using the same charts, eyepieces, etc. as Bill) that came in after that one (it was one of the first, if not the first, we got in stock) did not and apparently continue to not perform as well. I found the Ranger to be both brighter and and sharper at any given magnification than the ETX. This was especially noticeable at higher powers (around 200x)., where the Ranger was considerably brighter. Finally, having looked through many Meade (and Celestron) scopes, and having star-tested numerous of the above and several Rangers and Prontos, I must say that the Tele Vue products are VERY consistent in their quality. With Meade or Celestron, you COULD get a real cherry of a scope, but you also COULD get a real dog (I should know--my first 8" SCT form Celestron was awful, the second is as close to perfect as any SCT I've ever seen--lucky me!). With Tele Vue, I've only ever seen very good optics or the very rare cherry (which is hard to tell from the "average" Tele Vue Ranger/Pronto which would be "cherry" by Meade or Celestron standards). Don't take this as a slam to Meade or Celestron--I own scopes form both companies and love 'em, and also have many accessories form both. It's just a fact of life--you usually pay more for the good ones. What's so amazing about the Ranger is it's quality at such a low price. Right now, there's no other scope that can compete with it in the quality for the price market. - from firstname.lastname@example.org Harvey Mace wrote: >does anyone really know which scope gives better images for high power >work (x200+) using high quality eyepieces? Your question really gets to the primary difference between the Ranger and small aperture Mak-Casses like the ETX. The Ranger is designed to provide low power, wide field views. Its focal length is 480mm. The Tele Vue 4.8mm Nagler, for instance, will give you a 100x view. You need to slap on a 2x Barlow in order to get to 200x. At 200x, even a Nagler provides a true field of view of only 0.41 degrees. An object centered at 200x will drift outside the eyepiece field of view in 3 minutes. An extended object like a planet will kiss the edge within about half that time. The Ranger, an excellent wide field instrument, is not really at its best at such high magnifications. A longer focal length scope like the ETX is designed to get you in the 200x range more comfortably. Its focal length is 1250mm. The Nagler 4.8mm will give you 260x, the Nagler 7mm about 178x. No Barlow is needed and this is important since very wide field eyepieces like the Naglers already put a lot of glass between you and the object of interest. An clock-driven equatorial mount is a valuable asset, if you plan to regularly observe at mags in the 200x range. Clock drive lag notwithstanding (see Sky & Tel's review in the January 1997 issue), the ETX's motor drive is capable of keeping objects within the eyepiece field at high power. If you are looking for a scope that will be used regularly at 200x on the Moon and planets, then the ETX has a definite advantage over the Ranger--not an advantage in resolution, necessarily, but in oveall ease of use. * 2.9 How does the ETX compare to other instruments? Here are some comparison found on the net: - from R. Aguirre (email@example.com) Was wondering if anyone ever did a comparision on the Optical similarieies between an ETX a C-5 and a GP-102 (non ED) model. STRICTLY OPTICAL SIMILARIEIES WITHOUT TAKING INTO ACCOUNT ANYTHHING HAVING TO DO WITH THE MOUNTS OR COST. My first thoughts would be the Smaller ETX would be good, the GP-C102 would be better, and the C-5 would be best for planetary views. I've never looks thru a C-5, but I have seen an ETX on saturn using a 7mm Nagler and it was razor sharp, as was Jupiter. Conditions were under dark clear moonless skies. Thats about 180x. I've peeked thru a GP-C102 using the 7mm also and it was also fantastic at about 150x. Can the design of the ETX really hold a sharp focus out to 250 to 300x? Seems to be the claims of some non-ETX users? I suspect not but I dont know? How about the GP-C102? I figured it would be spent at about 200x. How about the C-5? I am just not to impressed with small Schmidts but this is only based on what I have seen in, for example, the Celestron Catalogs? Basically, i'd assume they would all be similar in overall performance for planetary sharpness though I'd guess the C-5 would win the limited Deep space contest. What makes the ETX design so impressive for planetary observing. Based on advertisements ( which I seldom believe with out first hand experience), shouldnt the ETX then be the star performer in this group in overall optical sharpness and performance. Or, shouldnt the refractor win the sharpness contest? If being somewhat similar in aperatures size or focal lenghts, could anyone really tell a difference? Now lets throw in a star performer, the AP 102 traverler. Why can this scope make claims to remain razor sharp at and above 300X. My guess is that this one would vaporize the ETX, GP-C102 and C-5 in every catagory? I've looked thru a traveler with the same 7mm eyepiece and a 3x televue barlow and was not impressed with the sharpness on both Jupiter and saturn. Looks like the 260x was over extending the upper limits of this scope, though probablly at 200x it would have been pretty nice. Having a large and heavy 10" Schmidt, I've been searching for a smaller light scope for quick 1 hr sessions in my back yard at a moments notice or for ultra portability. In order of appeal to me considering all factors, cost, mounts etc, My current direction is C-5, ETX, GPC-102 and Traveler. The traveler is definately the most desired, but the cost is pretty steep for a little scope. For some reason, I am just not attracted to any of the televue refractors, to me, the Traveler has that market covered completely. - from Loren A. Busch (firstname.lastname@example.org) Ralph I own both an ETX and a C5+. For ANY application (without considering the small size of the ETX) or viewing the C5+ outperforms the ETX. I base this on extensive testing this last summer setting the two scopes side by side and using the exact same eypieces in both. This is not suprising considering the additional aperature on the C5. There is no comparison on the drive bases. The C5 is supurb, the drive base /fork mount for the ETX sucks. I have removed my ETX from the fork mount and use it on a good tripod. Optically, based on the ETX scopes I have seen, they are a very good buy, excellent value for the dollar. The optics star test better than anything in the price range and better than a lot of products that sell for much more. But if you want a very portable scope of superb performance and can stand the additional size (and price) of the C5+ it is a better choice. (I actually have two ETX'x: one the astro mount, one the spotter. I have them mounted together as a fantastic binocular) - from Donald Tabbutt (DonTabbutt@worldnet.att.net) Hello Ralph, I have an ETX that I bought mainly for travel. However, I think it may make a nice guide scope for my 8" f/10 LX200 and I have ordered the Losmandy stuff to mount it. In the meantime, I used its tripod block to piggyback it on the LX200 last Sunday night for an A-B comparison. The short conclusion: there is no comparison; the ETX is a little scope and the 8" SCT is a comparatively big scope. The most striking and immediate difference is brightness. One plus to the ETX, though, is when focused on Capella it forms a perfect Airy disk with a single small diffraction ring...something I've never seen in the SCT, although it appears to focus as well...but no diffraction ring. Saturn was jumping around in the LX200 like I had lost "vertical hold", but was O.K. in the ETX...I guess proving small scopes handle bad seeing better than big scopes. On Christmas night I used the ETX by itself on Saturn and could see banding at 187X with just a hint of Cassini's division as a contrast change in the rings. But I couldn't see Tethys or Dione...just too dim. I see them regularly in the SCT. In short, I couldn't do an A-B on Saturn because of the seeing Sunday, but have had much better views in the SCT in the past. I even imaged the ammonia cloud storms on Saturn with a CCD camera last October through the SCT, and got images nearly as good as those published by Donald Parker in S&T's December issue. Until I read that issue, I thought the storms were some sort of image processing artifact. With averted vision Christmas night, I think I saw those storms through the ETX. They appear visually as ragged edges on the south side of the south equatorial band. On the deep space side there is really no comparison. One caveat...there is a lot of light pollution here, and I will have to do another comparison at a dark site. I put a .63 reducer on the SCT to even up the magnifications (about 48X) using the standard 26mm Plossl on both scopes. I looked at NGC 1857, a small cluster in Auriga mentioned recently on s.a.a. (they were having trouble seeing it through a Ranger), and saw it clearly and brightly in the SCT, but barely in the ETX. The same goes for other small clusters. They are there, but dim compared to the SCT. I used an O III filter on both scopes for M76 and NGC 7662 and saw them in the SCT (without the reducer) but not at all in the ETX. M31 was fine in both scopes, but M33 did not show up in the ETX (light pollution, I'm sure). Later, as M42 cleared the trees, it was nicely visible in both scopes, but again much brighter and more finely detailed in the 8". I couldn't see NGC 2024 in either scope. I didn't try splitting any doubles. By now, the Moon was rising, and after it cleared the trees I used all kinds of powers to look at it...up to 300X on the SCT and 187X on the ETX. Bad seeing caused me to back off, but I'd call it a draw on the Moon. Both scopes were clear, tack sharp, and very contrasty, with the same small details equally visible. Again, the SCT was brighter, but at lower powers I have to use an ND filter with it. The ETX was fine without a filter. In summary, aperture wins. The ETX meets my needs as a traveling companion and will probably make a good guide scope. The optics, in my experience, are superb, but it will not outperform a larger aperture scope with decent optics. The ETX mount is a different story I'll save for another post if anyone is interested. I hope this helps answer some of your questions. - from Allen Chan ( chana@andr.UB.com ) i brought the etx to a telescope shop to compare it with a C5. the shop had a TV pronto, so i compared this scope also. the salesman was the official second opinion in this comparison. first, we normalized the comparison by setting the three scopes to the same magnification. since the C5 has the same focal length as the ETX, we use the same type of eye piece in the C5. the pronto need a much high mag eye piece. we look at a gargoyle on the across the street. specifically, we looked into the dark mouth of the gargoyle to simulate low light conditions. the ETX was noticeable sharper than the C5, but the C5 was brighter. the pronto was a used scope and the image did not seem as clear as either mirrored scopes, so i started to ignore it. the ETX gave a cooler blue-ish tint to the image while the C5 gave a warmer yellowish tint. the salesman also thought that the ETX gave a sharper image that the C5. however, these test were done in daylight conditions. in night time astromony conditions, the larger mirror of the C5 might have a greater effect. for daytime conditions, the ETX won the comparison. * 2.10 Do I need a perfectly level surface for doing the polar alignment? Here is a thread found in sci.astro.amateur: This is a common misconception. For polar alignment, all that is necessary is that the RA axis [the ETX fork arms in this case] have to point to the pole. It doesn't matter one bit whether or not the table is level. A level surface makes alignment easier, but it is not essential. and the following: In article (email@example.com), Jonathan Silverlight (firstname.lastname@example.org) wrote: >I don't see how this works. If a polar mount is aimed at the pole >but isn't level it must be offset E or W and will drift >accordingly. Jonathan, If a polar mount is aimed at the pole, as you stated, (ie. the mount's polar axis is aligned with the Earth's rotational axis), then the attitude of the tripod is totally irrelevent. The important thing to keep in mind here, is that if the polar axis of the mount is properly aligned, you can forget about what's holding it up (ie. the tripod, pedestal, whatever...). However, it *is* more difficult to achieve a polar alignment using the "drift method" if your tripod is poorly leveled to begin with. * 2.11 Can the ETX be a first scope for a novice? The answer to this question is not simple ;-) One easy answer is yes, every telescope can be a first scope for a beginner! here are some articles: - from Cliff Newman (email@example.com) > I can't agree with this. The ETX is **NOT** a "beginner scope", any more > than a Questar is. Yes it is and I'll tell you why: people will buy this AND use it for the same reason they buy those cheap dept. store scopes: it looks like a telescope, it's really portable, and it is great for all the things that newbies (like me) want to look at. There is a lot of very good advice offered here and elsewhere telling new observers to stick with binoculars. This advice, while sound, will fall on deaf ears because new observers don't want to use binoculars; they want to look through a telescope. The ETX looks not just like a telescope but a high tech telescope. That's why it's going to become the best selling telescope in the world over the next few years (at least according to one experienced observer at a star party who got his first look through my ETX). And if you don't stick with astronomy you've got a killer terrestrial scope too. In my admittedly untutored view, what makes a really good "2nd" scope is a 10" Dob. I'll likely keep my ETX and move up to something like that that I can set up at my cottage and use it whenever conditions warrant. When I have to drive or fly someplace, I'll take the ETX. Cliff > A good 6" dob is roughly the same price (or slightly cheaper) and HUGELY > better as a first telescope than an ETX would be. > > Chris > > ---------------------------------------------------------------- > Chris Marriott, SkyMap Software, U.K. e-mail: firstname.lastname@example.org > Creators of fine astronomy software for Windows. > For full details, visit our web site at http://www.skymap.com - from ??? email@example.com (Leander) >...snipped... >Unless you live in a very dark site, I predict that you will not use your 8 >inch SCT nearly as much at home once you get your ETX. I know that I use my 3 >inch refractor at home much more often than my 10 inch dob. By the same token >I use my 10 inch much more often from my dark sky site. >P.S. Aperture always wins, but there are wonderful objects to observe through >any sized aperture from naked eye to world class observatory giants. Very good point. A lot of discussion has been ongoing on this thread about the advantages of larger scopes vs smaller scopes, with some valid points made by all. The usual recommendation for newcomers is to get a 6" or 8" dobsonian. Practically, however, this may not suit all buyers' needs. I think we have a tendency to forget that the needs of an individual newcomer may not fit with our standard recommendations. Do they live in an apartment. Are they in a dark or a light-polluted area? How much weight do they want to or are able to carry? Do they want to take out their scope in one piece, or in several pieces and set it up each night? How much time do they have for an average observing session? What are their interests ultimately, as well as immediately; do they hope to do astrophography, ccd astronomy, or visual only; planetary, deep sky or both? Comet hunting sometimes or primarily? Don't know yet? Do they know how to collimate or want to learn collimation? Will they be travelling by plane a lot? For many, the standard dobsonian may not be the best choice. A small refractor such as the Celestron 80mm or the Pronto or the Ranger on a decent mount may be better, and get used more; so might a small sct-type such as the C5+ or the new Meade. For some, even the lowly Astroscan may be the best choice. A C4.5 Newtonian might be better than a 6" dobs for many people. Or the dobs may be perfect. Rather than dealing with personal prejudices and preferences, we could better aid newcomers by addressing THEIR needs, not our needs foisted upon them. Big aperture is great to view through, and usually involves a scope which is a pain to set up, especially when you are tired or have limited time. Portability still gets a scope which will see all the Messiers, planets, and a good number of other items. If the scope can be carried out in one trip, set down, and begin looking, it will be used often. If people travel and want to bring their scope, a small one will get used while the big one stays home. Instead of buying the biggest aperture they can afford first, then wishing they had an easier to use portable, why not introduce them to the skies with a portable, then when they are comfortable with all they can see with this scope, get a light-bucket to see even more, with less confusion. Probably the one critical question is, do they want to do astrophotography? Well, then they will need a motorized equatorial mount; but they may still want to start with an alt-az, and upgrade later to a heavier motorized mount which will have to be polar-aligned (adding to set-up time), and may now involve multiple trips for set-up. We have a portable, a light-bucket, and binoculars, and the light-bucket gets used the least because of its 20minute set-up and total 90-pounds weight in 3 trips. Also, our viewing since moving to a light-polluted area is not as good, so the smaller Pronto actually does much better. Some nights, there is only enough time for a quick binocular view before the clouds roll in (1996 was SUCH a great viewing year...not). These are my opinions, and not everyone will agree. But I've gotten a number of family and friends into astronomy over the years, and did not recommend the same scope for all of them, because of the above considerations. Of note, though, they are all still using their telescopes, which is, after all, the only true ideal. - from Mark S. Cronan Chris Marriott (firstname.lastname@example.org) wrote: >with respect, Cliff, the fact that you've bought it (and lots of other >people will too) doesn't make it a good beginner's telescope. You can't >defeat the laws of physics - at the end of the day it IS only a 90mm >telescope which imposes SEVERE limits on its usefulness for astronomy. >Even a cheap 6" Dob is going to show far, far more objects than your ETX >will. >The ETX is a *great* portable telescope - I've got one on order myself! >- but I stand by my conviction that it is NOT a good "general purpose" >telescope for the novice amateur astronomer. Well Chris, I've got to disagree. For some reason you think a "general purpose" scope is what a beginner needs. You stress, in fact, the number of objects that can be seen. I don't think thats the appropriate criteria to judge a beginners scope. What a beginner needs is 1) Something simple to use. The ETX is simple to use, since it requires no real collmination every time you use it, and comes with alt/azimuth mounting system and tracking motor. 2) Something which will show you the "major" things to be seen. The ETX will show you pretty much any Messier object. It won't get you the horsehead nebula, but then a beginner should not be going after the horsehead nebula to start with. A beginner will instead be using, probably, a beginners book of objects. Such a book will list items which the ETX should be able to view without too much trouble. It will also get you good views of the planets, moon, and sun (with a filter). So, while it is not a "general purpose" scope, it is a "general beginners" scope, IMHO. * 2.12 Meade advertises a resolution of 1.3", is it true? There are several report claiming such a result, here are two: - from email@example.com (Michael Boschat) Michael Boschat ( Astronomer ) E-mail: firstname.lastname@example.org Atmospheric Sciences Phone: (902) 494-7060 Dept. of Oceanography FAX: (902) 494-2885 Dalhousie University Halifax, Nova Scotia CANADA, B3H 4J1 ASTRONOMY Web Page: http://www.atm.dal.ca/~andromed Date: Aug.5/6 Time: 0120 UT Location: Halifax, Nova Scotia, CANADA Lat: N44 Long: 63W Limiting magnitude (visual): 4.5 Seeing (1 to 5 - best to worst): 2 Instrument: ETX Spotting Scope 90 mm Makustov, f/13.8, 48x, 167x, 312x Object: The double star Xi Ursa Majoris, Jupiter, Comet Hale-Bopp Well, it stayed clear and I had a nice Airy Disk, so I went after the theoretically resolving limit of the ETX which is 1.3 arc seconds. The double star Xi Ursa Majoris according to the books is 1.3 arc seconds with companions of 4.3 and 4.8. So with 312x I focused on Arcturus till I got the Airy Disk, then doing some manouvering with the finder..ugghhh... I found Xi. Lo and Behold it was seen as 2 stars touching!!!!!!!!!!!! Gezzz...!!! I let out... It looked like this at 312x; (*) (*) /N the () is the Airy Disk |_ E So, it was seen without any problems....except for one that I just came across, I have slight mirror shift. When I wen back to Arcturus I had to re-focus a bit, so I will assume slight mirror movement. But, the ETX split to it's limit! I am amazed. Date and UT of observation: Aug.11/12, 1996 Location & latitude: Halifax, Nova Scotia, CANADA, 44N 63W Limiting magnitude (visual): 5.5 Seeing (1 to 5 - best to worst): 2.5 - 3 Instrument: 90 mm Makustov, f/13.8 Magnification: 48x, 167x, 208x, 312x Object: Eta Corona Borealis Category: Close double star of 1 arc second Description: Using the ETX focused on Epsilon Bootes at 312x to get the best possible image I then moved to Eta Corona Borealis. It appeared at moments of steady seeing as a small elongation. This shows that the ETX seems to be able resolution of near 1 arc second on excellent nights! I was amazed to see the slight elongation in a North East ( since the image is reversed ) direction. The components are 5.6 and 5.9 magnitude. Again the ETX, despite falling apart is showing it's performance in the optics! 3. What kind of accessories can I used on my ETX? * 3.1 Which tripod can I used? Chuck Faranda ( email@example.com ) I use a Bogen 3001 and have had good results, it's both sturdy and portable. * 3.2 Which cases/bags can I used? Meade ETX bag is too large and poorly designed. Many people find video camera bags to be much better and less expensive. * 3.3 Which eyepieces can I used? ETX is slightly different in it's construction than most scopes. You may find that certain wide angle eps have an obstruction in the field of view where the edge of the mirror is. I think that you would do well trying to complete a set of eps that is parfocal. Otherwise you will be adjusting focus, sometimes quite substantially. This can be a pain. In my severely limited experience I found that long eye relief eyepieces were extremely sensitive to the eye being aligned with the optical axis of the eyepiece, causing me to lose the view even with slightest movement of the head. The bottom line is TEST EACH EYEPIECE BEFORE BUYING! Most stores have no problem with you bringing your ETX into the store to try an eyepiece. Star Parties are great for comparing eyepieces as well. I tested some highly acclaimed eps and found them unusable on my ETX. get from metxug - from Fred Smith ( firstname.lastname@example.org ) I bought a 9mm Nagler to use with it, but I found the image to be not at all sharp - at least compared to the 26mm super plossl that came stock. BTW, the 15mm Panoptic was wonderfully sharp on it. - from Chuck Faranda ( email@example.com ) Hi Fred, I just got my ETX last week, so far it's great. I've used it with the 26mm Plossl and a 15mm Teleview with fine results. There isn't any collmination adjustments on the scope, so you'll just have to trust Meade's QA program, my scope was very well aligned. I think your problem with the 9mm Nagler may center on the fact that you are approaching magnification of 40 per inch of aperature. So the image may show signs of degradation. You may want to try the Nagler under dark, clear, steady skies and reevaluate the results. The quality of an image under high magnification (138X in a 3.5" can be considered high by some standards)in any scope is dependnat upon seeing conditions. - from Alvin Huey ( firstname.lastname@example.org ) I have used it with a 9mm Nagler, but my views are wonderfully sharp. I actually did the star test with the 9mm Nagler, and it turned out very well. Jupiter was sharp with the 9mm Nagler. I also used my 13mm Nagler with it and it worked out well also. Didn't try my 16mm Nagler yet, since I have a 15mm Ultrascopic, which I bought for this scope. Of course couldn't use my 20mm Nagler and 35mm Panoptic. (Wish I could...) About the tight fit with the finder, I fits but it rubs against the finder holder. I plan to take the finder out and put some kind of 1 power finder on it. Any suggestions, I'm a big Telrad user, I have one on each of my other three scopes. - from steve (email@example.com) > I recently compaired the 26mmSP that I got with my > LX200 with the one I got with my ETX. There is a > !/4" difference in length. One is 2 3/4" long and the other > is 3" long. I'm not sure which one came with what. > I thought the two eyepieces were the same but they > aren't even parfocal to each other. > > Does anyone know what gives here? > > Jim Jim; This is what the ETX manual says (in my words); "The 26mm Super Plossel that comes with the ETX is a special "low profile" version. It is optically identical to the standard model, just shorter for a lower profile on the scope. It is not going to be parfocal with the regular Meade SP line." * 3.4 Which barlow lenses can I used? I use TeleView x2 and it provides me with satisfactory service, especially with the 26mm ep. I have an 8mm ep and with that Barlow it is at the edge of usability, but Saturn looked quite decent. - from J HOPPER (JHopper@prodigy.com) I used a TV 2.5x Barlow with the 26mm on my kids' ETX, and it was excellent. The downside is that it's awfully stupid-looking, sticking way up. Ruins the whole "low-profile 26mm" concept. You also have to be careful not to slam the Barlow into the diagonal, there's nothing to stop it. I don't think they make the 2.5x or 1.8x anymore, now having 2x and 3x. No idea if they're just renamed or what. Barlows' power varies anyway depending how you use them. If you can get a used, mint one for $50 like I did you're doing well, I'd say. Don't think I tried it with my 15mm TV on the ETX, but that combo also worked OK on my 7", though not as well as the 26mm. Perhaps because on the 7" that's awfully high power for mediocre seeing. * 3.5 Someone told me that using a Barlow on the ETX will give a too dark image? Too dark for what? For faint nebulae yes, for Venus or Moon no. ETX is a small scope so almost anything can overpower it. Keep in mind that many of us are used to NASA space probe fly by pictures or Hubble space telescope shots and sometimes we intuitively expect similar pictures in our eyepiece. The truth is that in most cases no Earth based telescope regardless of size can give us that kind of detail and clarity as the space shots made with CCDs, to not even mention our poor ETX. 4. What possible mechanical modifications/enhancements can I make on my ETX? Get yourself a solar filter - that will extend your viewing time to daytime and give you more fun. Tuthill told me that he is coming up with a 90 degree viewfinder. For me this would be a must! Some kind of a due cap is also useful. One should be able to make one easily with black fabric and velcro. Tuthill also offers a camera piggy back mount, which allows one to use the lousy clock drive of the ETX to take long exposures with one's camera. Meade of course offers camera attachments to use ETX as a lens. I know that some people tried CCD cameras with success. But good CCDs cost much more than few ETXs put together. and also check at http://metxug.elendil.com/extfix1.html for the Declination Control Fix. * 4.1 Can I computerized the ETX? (goto function) Lets remember why we bought an ETX - small, inexpensive, easy to use. With computer it becomes complicated, hard to set up, unreliable and expensive. But if you really want to do this, JMI has the set up for you ranging from $399 to $699 with their installation. Call them at 800-247-0304 or outside of USA at 303-233-5353, fax 303-233-5359.They take plastic. 5. Contributors Many thanks to Jurek Zarzycki (firstname.lastname@example.org) who gave me lots of inputs. END OF FAQ################# ########################### FUTURE EVOLUTION TO BE DONE: NEW ENTRIES: FINDER ------ I find the finder scope to be almost worthless, given its position on the OTA. I think I would like to replace it with a small unit finder. Any recommendations? COLLIMATION ADJUSTMENT ---------------------- Finally, am I correct in believing that there are no "user correctable" collimation issues with a Mak such as the ETX? I have read from many postings that the optics on the ETX are potentially excellent, when Meade quality control passes muster. What is the recommended way for a novice to judge the optical quality? (Is that true, about no collimation screws. I thought that the three hidden hax screws in the plastic mirror mount is it, even tough they my not be evenly spaced.) Read the S&T May '95? Issue about star testing, or try Suiter's book "Star Testing Astromical Telescopes. MISC COMMENTS ------------- Luis Arg|elles wrote: > > I'm in the process to purchase my first scope and I wonder if this is a > good scope. I've had one for seven months but haven't used it much since last Fall, given the rotten weather arond Toronto this winter. Finally got out this week on a so-so night and remembered what it is I like about the ETX. > > #1.: Portability The whole works fits into a bag about the size of a smallish camera bag and weighs about 15 lbs. I use a Manfrotto 144 tripod which increases the load by 50% or so. > #1.: Quality optics Definitely. As luck would have it another chap showed up with a Pronto (that's the one with the 2" focuser, right?) and we agreed that he had slightly more contrast than I had but image quality was otherwise not very different and his scope cost about twice what mine did. I also had the advantage in being able to apply more magnification (a dim and shaky image of Mars at 250x, but then it wasn't great seeing). I hadn't polar aligned very well, so keeping Mars in the eyepiece was a frustration; but then the Pronto had no clock drive at all. One thing I learned: an experienced observer with an LX200 on an equatorial mount, had Mars at 100x at the same time as me. His image was a lot brighter than mine, so bright he put in filters to dim it down. At 200x he couldn't get an acceptable image either due to conditions. So on an average or below average night I don't see any huge advantage to the bigger scope - although I'd kill for his drive. > #3.: Easy operation The biggest advantage to the other scopes, especially the LX200 was the size of the controls. The tiny focusing knob on the ETX makes focusing kind of fiddly and nearly impossible with gloves. Otherwise, it's a really easy scope to use and if you take the time to polar align properly the clock drive will keep an object in the eyepiece long enough for a good, hands-off, no shake look. BTW, I don't think the finder scope is totally useless, as some have suggested, but I did add an Orion EZ Finder 1x finder and that helps in polar aligning and most other searching that I've attempted so far. #4.: Very basic astrophotography No joy here I'm afraid. I've taken some moon shots but that's about it I would think: star trails of course, but the clock drive is not up to keeping an object centred beyond a few seconds or tens of seconds. Even getting an object centred and then waiting for the backlash to take up (and that does seem to take 20-40 seconds) will see the object half way out of the field of view. > I would like to hear your opinions. It's a really good little scope for visual observing. One of the nicest things about it is the comments from experienced observers: they nearly all love the image and are impressed with the performance. You can buy more aperture for the same money but you can't take those scopes on a plane with you and you likely won't want to haul them too far by bus either. I don't suppose I'll be in love with this scope forever, although I've kept my first wife for over 30 years, so who knows? Hope this helps. Cliff ==============================================================================
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