Last updated: 31 July 2004
Subject: ETX 60/70 Sent: Friday, July 30, 2004 14:34:10 From: email@example.com (firstname.lastname@example.org) I have an ETX60 and I also have an ETX70 OTA that was given to me. The OTA's are identical. The 60 has an adapter that makes the 60mm objective fit into the tube. The 70mm objective fits snug without the adapter. Except for this difference the tubes appear completely identical.
Subject: ETX Coma and focus problem ??? Sent: Friday, July 30, 2004 12:46:14 From: Spam @ K3PGP dot ORG !!! (email@example.com) Perhaps you can post this somewhere on your website and see if anyone has a clue as to what the problem might be with this scope. I was in need of a short focal length refractor and when I came across a '-factory refurbished-' ETX-70AT from Meade Factory Outlet complete with tripod, accessories and Autostar at a reasonable price plus FREE shipping I decided to give one of these a try. The scope is covered with a 1 year factory warranty. I have been in astronomy for approx. 40 years using both homemade reflectors and refractors as well as a couple of ETX-90's and an ETX-125 so I am no stranger to Meade equipment or astronomy in general. You can see some of my work at http://www.k3pgp.org. The problem I am having appears to be out of focus light that is reaching the eyepiece. It looks identical to the problem one has when using a short focal length fresnel or condenser lens to project an image on a piece of paper. There is a definite point where the incoming light is brought to focus but around that image is a LOT of out of focus energy which greatly reduces the contrast. But unlike a fresnel or condenser lens I see no chromatic aberation, color fringes or anything like that. The brighter the object of course the worse this problem appears. The scope is next to useless for terrrestrial viewing during daylight hours. I can't even read a large sign across the street as it's extremely smeared even though there is a definite focal point. Furthermore, if I focus the ETX-70 on a dim light across the street during darkness everything looks pretty much normal as long as I keep my eye directly in the center of the eyepiece. If I deviate ever so slightly off center I see a secondary image of the same light source with an expanding tail (coma). The further off center I move my eye the larger the tail until I get to what appears to be approx. 2/3 of the way out from the center of the field of view when the seconday image cuts off abruptly. The boundary where the secondary image cuts on and off is circular. After thinking about this problem I came back inside and found a black piece of cardboard which I cut an approx. 1 inch diameter hole in the center of. When I hold this in front of the objective lens of the ETX-70 all of the above problems go away! However this only occurs if I keep the 1 inch aperture directly in the center of the objective. If I deviate ever so slightly off center the problems starts to come back. If I place the 1 inch hole near the edge of the objective there is still a lot of light coming through the eyepiece but it's impossible to bring it into focus. After seeing this I thought perhaps something had fallen off inside the scope, like a light baffle, etc. but I see nothing loose. It's starting to look to me like the objective itself is defective. Like I said it kind of reminds me of the problem one sees when trying to use a short focal length fresnel, condensor or cheap plastic lens minus the chromatic aberations. Anyone have a clue as to what is going on? Should I send this thing back to Meade and make them fix it? I'm assuming I'll have to pay shipping even though the scope was delivered this way. I've never heard anyone else comment on problems like this with an ETX-70 and I can't believe this is normal performance as the scope is pretty much useless. PS - Firing a laser pen through the eyepiece and focusing the image across the street on a white building displays the same coma and focus problem. Doing the same with one of my homemade short focal length refractors displays a nice round dot. I've swapped eyepieces etc. and the problem is in the ETX-70. I tried to use one of my CCD cameras to take a photo through the ETX-70 to show what I'm talking about but the problem is so bad I couldn't even get something worth sending... K3PGP - John -=Mike here: Got me stumped. Try an experiment; using one of your rear port adapters, try using an eyepiece at the rear port (sufficiently shielded from stray light) and see if the problem remains. Let me know.
Although I tested the rear port when I first got the scope with identical results I just went outside and repeated the test just to make sure I didn't miss something and the results are the same. It's dark here now so stray light isn't a problem but it's overcast so I used a street light some distance away. Same focus problem and coma on both the 90 degree and rear port using a known good 25 mm eyepiece and the 25 mm eyepiece that came with the scope. I don't understand what I'm seeing. This is a very simple refractor scope. About the only thing I can think of is the objective lens is defective. I'm not sure but I assume this lens is glass and consists of at least two lens although it's performing like a cheap short focal length plastic condensor lens! If it does consist of two lens, I'm wondering if the two lens were assembled incorrectly. If one lens was left out I would assume the focal length would be grossly wrong but the FL seems about right. The lack of any chromatic aberation problems would also indicate that all elements of the objective lens are indeed there. If the scope weren't under warranty I'd tear it apart and find out what is going on but I'm starting to think it needs to go back to Meade. After all it was returned at least once before, refurbished then sold to me. I'm wondering if what I'm seeing is why it was returned the first time? Remember it came from the Meade Factory Outlet store and was sold as a refurbished scope with a 1 year warranty. The view through one of my cheap Meade 6 x 30 finder scopes puts the view through the ETX-70 to shame!Mike here: Since it is not chromatic aberration you are seeing I would suspect that something is amiss. Contact Meade and let me know what happens.
Subject: re: ETX 60/70 Sent: Wednesday, July 28, 2004 19:54:19 From: Richard Seymour (firstname.lastname@example.org) Will a 70mm fit in a 60 mount (or vice-versa)? Maybe. There have been -two- models of ETX70 (and therefore 60) over the years... the "early" (power and autostar plugs in base) and the "later" (all plugs on side of fork, rotate with telescope). I believe that the entire tube-support is different between the two families. In any one -family-, the ota barrel is the same size (buried somewhere on Mike's site are ancient photos of a 60 to which someone added a 70, then 80mm, lens. I think Duct Tape must've been involved....) have fun --dick
Subject: ETX 60/70 Sent: Tuesday, July 27, 2004 15:09:34 From: Ray (email@example.com) Quick question for you and this one I'm quite certain that you will know right off the top of your head. I bought an ETX tube assembly awhile back and have been using it for a finder. Just ran across an ad for a brand new autostar mount for the ETX 70. Won't the 60 fit the 70 mount? It's difficult to tell but as far as I can tell in the photos it looks like the only difference in their size is the objective cell and lens? I know the tube is like way big for the 60 mm and there certainly is enough room for the 70 but thought that I would ask anyway. Thanks for your time Mike! Best regards RayMike here: You didn't say what size ETX OTA you have but see the article "Putting ETX-90 on ETX-70 forks" on the Telescope Tech Tips page. If you have the ETX-60 tube (which it sounds like you might have) then you'll need the proper adapters.
Sorry I thought that I did, must have gotten ahead of myself again. I have a ETX 60 tube and the opportunity to buy the autostar base from a ETX 70. The guy took out the 70 to use for a finder scope and everything is brand new. My question was will the 60 tube fit right into the forks that the 70 used? Thanks again, RayMike here: You may need some additional support on the tube adapters; I don't have an ETX-60 to check.
Subject: ETX 70 on Ebay Sent: Sunday, July 25, 2004 22:27:33 From: Roger Eggleston (firstname.lastname@example.org) I was looking over your forum, and found it to be interesting. I used to be crazy about Astronomy until my late teens, but "making a living" kind of took my attentions elseware. I am thinking about getting back into the hobby, and would like to eventualy build my own scope. In the mean time, I saw a Meade ETX 70 on Ebay at $33 with 3 days left. I know it will go up, but it seems like a really good buy, and I know Meade scopes are real nice. Is this something I should go for at probably $100+ by the time it ends? I appreciate your time Mike, and your opinion. Regards, http://http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3829723967 Roger EgglestonMike here: The ETX-70 is a fine telescope but has its limitations. Read my comments on it linked from the top of the "ETX-60, ETX-70" feedback page as well as that from others on the Helpful Information: User Observations page.
Subject: re: ETX 70 problem Sent: Sunday, July 25, 2004 21:47:25 From: Richard Seymour (email@example.com) Something which is often unbelievable is how many turns the ETX70 focus knob may require. It is 50 (fifty!) turns from end-to-end. The goal (when pointed at a star) is to turn it to produce the -smallest- image possible (a tiny point). good luck --dickAnd an update:
From: Faraaz Ahmed (firstname.lastname@example.org) You were right, the focus knob was disconnected. I got a new one. seems to work fine. also is aligning it hard, I was able to manually see the moon etc, but when aligned the scope pointed to some place where i couldnt locate any stars. thank you for your time and help
Subject: Alt Knob ETX-70 Sent: Sunday, July 25, 2004 03:08:05 From: Ledley (email@example.com) The Alt.knob on my ETX- 70 has to be cranked down REALLY TIGHT in order to engage.Is there an "at home" fix for this?Thanks in advance for your reply, GREAT site and service to ETX users. Greg Ledley Ridgeway OhioMike here: There are several DEC axis articles on the Helpful Information: Telescope Tech Tips page but none specific to the ETX-70. But you might look at those for ideas. Use the "ETX-70AT Repair Guide" as a guide.
Subject: ETX 70 problem Sent: Saturday, July 24, 2004 00:30:24 From: Faraaz Ahmed (firstname.lastname@example.org) Hi. I read ypur review on the Weasners website. I was hoping you could help me. I just bought an ETX 70. Now I am clueless about getting it work. I cant see anything through it except blurly light. I did all the check ups, made sure the flip switch is in the right positon but still nothing.I turn and turn the focus screw but nothing happens. It has been driving me crazy. please assit me. the scope aligns itself but i can still not see a thing. What do i do? Any help you give will be much appreciated. I nned to fix this quickly as I need to give to my brother when he comes over and would love to have it working by then. Thank You for your time FaraazMike here: Have you read the manual? Have you tried to focus on a distant land object in the daytime? Are you using the supplied 25mm eyepiece? The focus knob can require MANY turns to reach a focus. You say you are turning the focus knob but nothing is changing. Do you mean there is NO change in image quality at all as you turn it?
I have read the manual many times overs. trying to focus on a distant land peice doesnt work eitheir. there is no change despite many focuses. it is as if the focus knob doesnt move.Mike here: Since it is new I recommend returning it to the dealer for a swap. It sounds like focus shaft may be disconnected (which you can verify by watching the objecting lens housing as you turn the focus knob; it should slowly move forwards or backwards along the tube).
Subject: RE: Autostar compatibility question Sent: Saturday, July 17, 2004 09:31:14 From: Ed (email@example.com) Many thanks for your response. I have followed the link to the Meade site and read through the article. It looks as though buying the #497 for my ETX-70 is the best way forward. I'm really grateful for your advice Mike. Very best wishes Ed P.S. I should have mentioned that I am based in the UK and I hadn't managed to get such a clear response from any of m contacts here. Thanks once again and I'll keep an eye on your web site.
Subject: Autostar compatibility question Sent: Friday, July 16, 2004 23:04:14 From: Ed (firstname.lastname@example.org) I own an ETX-70 AT which came with the standard 494 autostar. I would like to connect the unit to my laptop to download the latest software however, I recall some advice that you provided some time ago which suggested that a possibly better alternative would be to consider replacing the autostar unit rather than purchasing the 506 cable. An opportunity to purchase a new 497 controller has come along and I would be grateful if you would let me know if this controller is compatible with my ETX-70. Alternatively, a link to the article that I recall reading would be of great assistance. Many thanks in advance Ed P.S. I purchased your book 'Using the Meade ETX' and wanted to let you know how pleased I am with it. Very well done.Mike here: As stated on Meade's Autostar Update page (http://www.meade.com/support/auto.html) the #497 is compatible with all ETX models. Since there is NO update available for the #494, having a #506 cable will only allow you to control the ETX-70 from a computer.
Subject: [none] Sent: Wednesday, July 14, 2004 09:22:09 From: Stacey_McGlasson@Dell.com First off I would like to congradulate you on an excellent web site,, packed with valued information. I have a question, and cannot seem to find an answer to it. I figured you would know best. I am new to astronomy and telescopes, and my pick for the first telescope has lead me towards the Meade ETX 70AT, I was just wondering if it would be sufficient, or should I go for the ETX 90 ? Thanks in advance for any help givenMike here: Glad you like the Site but did you see the notice about first time visitors should read the Email Etiquette page? Your message was originally deleted UNREAD as SPAM due to the blank Subject line.
Subject: Merits of ETX-60 vs. ETX-70 - worth the upgrade? Sent: Saturday, July 10, 2004 15:07:30 From: Tyler Nagel (email@example.com) I have a chance to buy an ETX-70 to replace my ETX-60, and then a chance to sell the ETX-60 for what I paid for the 70. In other words, I can upgrade free of charge. All things being equal, would you say that the ETX-70 is a more satisfying telescope than the 60? Is there any regard in which the 60 is superior to the 70? I have a good selection of eyepieces (I have the celestron kit) as well as a NexStar 114GT. I use the ETX-60 the most since it is so quick to set up. Would you say that I should upgrade? Thanks so much for your advice, Mike. I appreciate the site. TylerMike here: The only difference is the 10mm of aperture. But that can make a difference for some objects. So since the cost of upgrading is nil, I'd suggest doing it.
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