Last updated: 27 November 2007
This page is for user comments and information of a general nature or items applicable to all ETX, DSX, and DS models. Comments on accessories and feedback items appropriate to other ETX and DS models are posted on other pages. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.
Subject: etx125 backlash on focuser knob Sent: Monday, November 26, 2007 15:18:10 From: jon (firstname.lastname@example.org) jon from uk here hey what a good site you have, can you patch me in to a section dealing with my prob. see you later regards jonMike here: Need some clarification; do you mean that when you turn the focus knob the focus doesn't change immediately or do you mean that there is some image shift or is there both? Have you modified the focus knob (like with an electric focuser)?
no mods, a bit of both id say, seems too easy to turn as well.Mike here: Do you feel comfortable disassembling the tube assembly? You can easily get the optics out of collimation and recollimating the ETX is not a simple task so you could make things worse if you are not careful (and even if you are careful). It is possible there is a worn component on the shaft/mirror assembly. How old is your ETX-125?
thanks for replying, its 2 months old i bought from usa, its an awsome thing to look at, i keep polishing it, ahh ok im a perfectionist, there is a bit of miror shift, not as much as my recent 8 " cass, what was that about turning the focus knob as far as it goes maybe anticlockwise then loosening the knob and reseting it , cand really remember what its supposed to do. cheers mikeMike here: Some image shift is normal with the Maksutov-Cassegrain design. Since it is new (but under USA warranty) you probably don't want to disassemble the tube. Running the focus in and out can loose/remove any debris that might have found its way in around the shaft or tightness on the mirror movement mechanism. It probably won't help in your situation but it won't hurt either.
ok see you later
Subject: DS-2000 tripod into manual Alt-Az. Sent: Thursday, November 22, 2007 21:32:29 From: The Brown Family (email@example.com) Still loving my ETX-90 M! Here's a Tripod tip I'd like to share. I had a single arm DS-2000 mount with 494 Autostar, and I mounted Orion's 4.5 inch f/4 OTA to it, a pretty good combination, but alas, the batteries leaked inside the housing (beware of cheap batteries!) and ruined the drives! As a solution, I unbolted the lower housing (9/16 inch bolt) and removed the AZ drive, therefore freeing up the drive base. I reassembled it exactly as it came apart, used a little grease on the washers, and adjusted the tension using the 9/16 inch drive base bolt. The mount now makes a very nice "Grab-and-Go" unit! It moves easily, both axis are easily adjusted (use the side knob for altitude), and can be lifted, with OTA, with one hand! This would make a good mount for a small ETX series tube, all that is needed is a little imagination to mount the OTA. I hope this helps! Kind Regards, Chris Brown
Subject: New Finder for an Old ETX90? Sent: Wednesday, November 21, 2007 18:18:23 From: JAMES W KREHMKE (firstname.lastname@example.org) looking at the new ETX90 (Not the ""PE" model) I see that it has the MRF red dot finder. I have one of these on my refractor and love it. Wondering if there's any possibility of replacing the lame finder on my ETX with one of these? Is the mounting point compatible and if, so, is the mount available as a separate part? thanks. -jwk-Mike here: There are some red-dot and 1X finderscopes discussed on the Accessory Reviews: Finderscopes page.
Have seen those, in fact there's one on my ETX right now, on a kludged mount that clamps around the OTA. Was hoping that the new standard setup would retro onto my classic ETX. That would make a lot cleaner setup and eliminate the counterweight necessary to balance the current setup.Mike here: Oh, you want to mount the LNT/Smartfinder from a PE model to your older ETX. See the articles "Adding a LNT to a non-LNT Telescope" and "Adding a LNT Module" on the Helpful Information: Telescope Tech Tips page.
Subject: Re: RA slop Sent: Tuesday, November 20, 2007 11:30:41 From: P. Clay Sherrod (email@example.com) You have indeed found the only solution to the problem for those scopes which exhibit very bad flexure. Glad you were able to make this work for you! Dr. Clay ------------- Arkansas Sky Observatories Harvard MPC/ H43 (Conway) Harvard MPC/ H41 (Petit Jean Mountain) Harvard MPC/ H45 (Petit Jean Mtn. South) http://www.arksky.org/ ----- Original Message ----- From: "Terry Godfrey" Dear Dr Clay For years, and probably since I purchased my ETX 125 in 2003, I have experienced slop in the RA axis. This slop is detected by being able to rock the RA axis back and forth some 3 degrees AFTER locking the RA axis. With the ETX on its side and the base plate removed it was clear that after locking the RA drive there was NO slippage of the clutch plates OR any slop in the gears or mountings yet by lightly gripping the periphery of the base the whole assembly was able to be rotated some 3 degrees! I discovered the cause of this movement after removing the lower (driven) clutch plate. This clutch plate has a transverse slot that mates with a transverse key on the RA axle and the tolerance between slot and key is very poor allowing the slop described above. I found the amount slop was way outside the capability of adjusting percentages on the Autostar to improve matters. My solution was to make a replica clutch plate with a slot that tightly matched the key on the RA axle. This eliminated the 'slop after lock' but was time consuming solution to the problem. You must have come across this problem when "supercharging" customers' telescopes; how do you get around this fault? If it's a trade secret I'll understand but living in UK, it is a bit far to send you my ETX for a supercharge. Kind regards Terry Godfrey P.S I reported my findings to Mike W's fantastic website.
Subject: Dust cover too tight EXT-125PE Sent: Monday, November 19, 2007 13:26:58 From: Havens (firstname.lastname@example.org) The dust cover is on so tight it will not come off. I received an EXT-125PE three days ago at my office. It is brand new. Following the step-by-step instructions I got no further than removing the dust cap. It would not unscrew. In fact the lens assembly at the end of the optical tube would start to turn. I had my associate hold the OT and lens assy. as I attempted to remove the dust cover. It wouldn't budge. The shipping box sat unopened in my office so the scope was sufficiently warm. Meade did not offer any advice beyond shipping it back to the dealer. Do you have any suggestions? I am shipping it back to the dealer tomorrow. Best regards, WilliamMike here: A common technique is to use rubber gloves or a rubber "jar lid opener". Grasp the cover with the rubber and grip it. Hold the corrector lens housing and tube so that they don't turn. The try to unscrew the cover. It should come off then.
Subject: Used ETX 125 and hard stops Sent: Sunday, November 18, 2007 17:53:19 From: Joseph Redman (email@example.com) I've searched for a prior report of this particular issue, but couldn't find a similar issue on your wonderful website. Perhaps I just didn't look hard enough. Let me know if I didn't, but if you could help, that would be terrific. I just recently got a used ETX 125EC with a new Autostar (running 43Eg.) The optics looked great, no scratches or dust that I could tell. It did have some wear and tear on the outside (missing view finder scope & broken RA locking knob.) It was sold "as is" and cheap ($100) so I knew there needed to be something wrong with it but was willing to play the odds - the functioning autostar itself was probably worth more. The drive motors appear okay and everything trained fine. However, when it came into alignment, I keep hitting the a hard stop near the South as the tube swung from North to South clockwise. After a little research in your site, I think I've found the issue, but don't know an easy (read cheap) solution. With the RA lever unlocked, the unit only turns about 340 to 350 degrees from hard stop to hard stop. From what I can determine this behavior is incorrect and it should turn closer to twice around - maybe 720 degrees. Any ideas on a corrective action? Thank you for your time. Joe Redman MassachusettsMike here: Yes, it should rotate almost twice around. There is likely some obstruction preventing full rotation. You can open up the base and have a look. Many times it is a wire that is catching. Use caution so as to not cut the wire. There could also be some debris that is catching. But opening up the base may help you isolate the culprit.
Thanks. Yeah, something is definitely wrong. I popped the bottom base plate off and all wires seem okay; nothing getting tweaked as I turned the base CW and CCW upside down. The center wire has a little bit of play at both stop points, so I don't think it's getting snagged. (Photo attached.) Looks like I'm going to need to remove the base from the fork module to take a better look. Seems like a pain with the wire snipping and reconnection, but nothing too scary. The RA clutch unlocking lever is going to be the toughest piece for me. It's broken already and that little locking screw seems impossible to remove - looks striped already. I know I'm going end up damaging it further. If I can pester you a little further, in your opinion is this something that can be drill out with a mini drill bit and then later something improvised as a replacement? Again, I didn't spend a lot of dough on it; worst case, it becomes one honking rifle scope - just kidding. :^) Thanks again, JoeMike here: Well, you may be able to drill things out but be certain to have a solution in mind. You could always mount the OTA on another tripod: see the article "ETX-125 on a LXD75 Mount" on the Helpful Information: Telescope Tech Tips page for one such idea.
If I come up with a workable and interesting solution that the community might benefit from, I'll document it and forward it on to you. Thanks for the great web resource and you're quick responses!
Subject: RE: ETX125 Azimuth lock Sent: Friday, November 16, 2007 17:05:47 From: Chris Mahar (firstname.lastname@example.org) Ha! That's excellent Terry. I also had a new RA aluminum clutch plate made by a machinist friend with one thousandth tolerance (down from 8 thousandths), and all my slop is also gone. I did a full reset, motor calibrate and training sequence, and had 5 out of 5 goto accuracy the first night out, though I still have a bit of creep after beep. I'm thinking that even with the RA clutch tight on the drive gear it will still slip until that key catches the slot, no matter how much grease you remove, no matter how polished and flat the mating surfaces of the clutch plate. I did all these things and still had my slop, about 2 degrees by my estimate. To replace the clutch plate I did have to cut and re-solder the 4 colored wires that run through it. Fortunately they are plenty long. Unfortunately they are insulated with some sort of very tough slippery Teflon or other such plastic, and were difficult to strip properly, even with good sharp automatic strippers. I ended up using heat of the soldering iron to strip the wire. Then I tinned each end, bent each wire into a tiny hook, and soldered the hooks together after first slipping on some small heat-shrink. Cmahar
From: Terry Godfrey (email@example.com) Thanks for the link - very useful information. The paper shim is certainly easier and quicker than machining a new clutch plate (which is what I have just done!) On my version of the ETX125 the clutch plates are much more substantial and a more complicated design than the one shown in the article but it still relies on a slot and peg arrangement for the final coupling which is where a huge amount of slop can be generated which simply cannot be fixed electronically by adjusting percentages. Cheers Terry --- Original message: Hi Terry, Glad you are well on the way to curing your clutch problem. This article may provide the finishing touch. http://home.socal.rr.com/hotweb/enh/etx.html Scroll down to the section headed "Improving the RA clutch". The shim solution is very simple and might be just what you need to counter any remaining slop in your newly machined plate. Regards, Mike
Subject: Electric Focuser & More ... Sent: Friday, November 9, 2007 16:58:37 From: Tom Farrell (firstname.lastname@example.org) Well since I last emailed regarding problems with electric focuser, It's funny, the whole thing broke. And upon calling Meade well, things do seem to be changing. I'm told that the Electric Focuser for ETX 90 & 105 is no longer in production. No details as to why, bug I evoked a chuckle when I suggested that it might be because the focuser kind of "sucks" (locks up, presses up against right fork arm creating friction. I had asked whether a more worthy replacement was in the works or how else Meade might honor its warranty and this info is pending. I also had a warranty issue regarding a perforated rubber eyeguard on my 26 mm Super Plssl eyepiece, something I've been talking to them about since last summer. Sometimes they say they eyeguard alone can be replaced, sometimes that the entire eyepiece must be replaced. Today it is the entire 26 mm Super Plssl eyepiece which is to be shipped to me given my proof of purchase. And all at my shipping expense, regardless of my having reported this during the summer and with a long litany of reasons as to why I should be spared the shipping costs. Well, it does not cost much to ship one of these eyepieces anyway. But and I hate to be this way I am hearing a BIG difference in Meade's customer support in less than a year and generally deterioration in customer support reflects a company's overall downfall. I HOPE this is not another example of a great product falling victim to bad management. But when I consider how, 20 years ago the ONLY color TV for me was a Sony where now I would not buy ANYTHING Sony manufactures yes I am worried about Meade. Only manufactured device I know of never to go downhill over time has been Honda cars. They just cost an arm and a leg is all. And are worth it. Sounds to me like there may come to be a big EBay market for Meade ETX parts before long. I'm not liking how this is sounding. Well I know they already discontinued ETX 105. Maybe now also ETX 125. Or maybe the ETX line is about to be supplanted by something better from Meade. Will be interesting I guess. I'm going to learn to do my own repairs anyway, that's for sure. TomMike here: Meade, like other companies, is undergoing a transition. Who knows how it will turn out. But consider all the "death watches" that Apple had in the 1990s and look at them now. Perhaps all Meade needs is a new CEO like Steve Jobs to get them back on top of their game. I would consider it but they likely won't offer it to me!
You don't want to live in LA anyway, right? I appreciate your lending some validation to my suspicions, since, in some respects, I am a bit of a disgruntled customer. You certainly are right regarding Apple, which has had at least two big renewals and looks to be possibly on the verge of overtaking icky Windows Mobile which previously used marketing power not a better product to turn Palm OS into what it is today. I had noted only this weekend, when helping a friend with her new telescope, a DSX 90 (new to me!), that Meade is doing kind of a "Sony" to hit a lower price point a bit cheaper to produce, looks a lot like another manufacturer's equipment. (My friend got it at Sam's Auction for about $250, wow!) I do hope it works out for them. Just reading their company's history tells me they deserve to survive. Where companies like Microsoft really don't. And of course ... a lot of who survives depends on who has the most money and clout in consolidations and whatnot. I kind of suspect we are not too many years now from where a lens of solid state electronics perhaps telemetry from off-world light collectors from which one can rent time may provide much more bang for the buck in telescopes. Guess we'll see. I still really like my telescope. Thanks for the insights. Tom PS. Heard the fires stopped. Good!Mike here: CEO of Meade and live in California vs stay retired and live in Arizona. Decisions, decisions, decisions... Yep, fires essentially out now. None were close to us.
Subject: big changes in holmes and latest m31 image Sent: Thursday, November 15, 2007 14:53:07 From: PETER SMITH (email@example.com) Compare the two images of Holmes from last night and tonight... http://www.btinternet.com/~psmithuk/AstroPhotos/C17PHolmes/C17PHolmes_14-11-2007.jpg http://www.btinternet.com/~psmithuk/AstroPhotos/C17PHolmes/C17PHolmes_15-11-2007.jpg Its seems to have gone really dim and no noticeable bright centre... Also here's my latest M31 Image approx 45 mins total Exposure http://www.btinternet.com/~psmithuk/AstroPhotos/m31/m31_80-200_14_11_07.jpg Tonight I tried some imaging in Fits3P format but for some reason its all gone "fits" up :( which is annoying... The fIts Liberator plug-in for Adobe CS3 doesn't recognise them...Hopefully will be able to get them back through Autostar Suite IP .... Regards, Peter Smith UK
Subject: electronic controller of etx 125 Sent: Wednesday, November 14, 2007 04:51:19 From: firstname.lastname@example.org (email@example.com) Hello to every body, I have a little problem I hope you can help me with. The two mode screw on the back of the electronic controller of my ETX 125 are missing. It was bought that way. I bealive I need at least one crew in the "B" slot to be able to use the 125 on the polar mode. The scope was bought in the States and brought to me to Turkey by a friend. I live on the Agean coast of Turkey . It is impossible for me to take the scope back to the shop or to a service. I will be greatfull If you can tell me what kind of screws I need to solve this problem. Thank you very much in advance for your help. Cem KaranMike here: I'd like to be able to tell you what size screw you need but my telescopes are all packed for my move. Hopefully someone will respond with the size. If you take the handset into a dealer they may be able to help but the handsets haven't shipped in several years so they may not have one to get the screw size.
Thanks for your reply Mike. unfortunatly there are no Meade dealers arround where I live. I hope someone responds.
Subject: Re: ETX125 Azimuth lock Sent: Wednesday, November 14, 2007 04:52:55 From: Terry Godfrey (firstname.lastname@example.org) So far: When I clamp the RA drive with modest force sufficient to prevent slippage of the clutch plates there is 3 slop in RA rotation. Further tightening of the clamp stops this slop but the force required is higher than I would like to apply. Experiment: With sufficient tightening of the RA clamp to prevent slippage BUT allowing RA slop, when using the hand controller with the scope pointed at a terrestrial object (Alt Az mounting) reversing direction does NOT appear to be a problem! I had assumed that when reversing direction, the drive system would have to take up these 3 of slop but the time taken to observe a change of direction when looking through the eyepiece at the terrestrial object is the same as when the RA clamp is "over tightened" to prevent the RA slop. Typically, with a speed setting of '3' it takes about 6 seconds to observe a change in direction. I am concerned that with "normal" RA clamping (allowing the slop) the GOTO accuracy will be frequently messed up if the scope can move by up to 3 in RA if it is accidentally knocked. I note that as the lower clutch plate (which has a transverse slot across it) is screwed on to the shaft, it engages with a transverse key. There is quite a lot of play between slot and key, could this have anything to do with the RA slop? Best regards Terry GodfreyMike here: You can adjust the "backlash" amount (the delay you experience) by adjusting the "percentage values" in the AutoStar. There are some articles on this on the Helpful Information: AutoStar Info page. That may resolve your concern. As to a mechanical reason for the slop, there could be several reasons, including what you have seen. Others would include worn gears, loose gears, too much lubrication.
I have no problem with the 6 second turnaround and have tried percentage values up to a massive 90% without any noticeable improvement so I am back to a nominal 15%. I have done the usual Calibrate Motor and Train Drives. Thanks for your help in this. Best regards Terry GodfreyMike here: OK, so we are back to a physical solution needed if you want to eliminate this. You will likely need to disassemble the entire base unit. Or you could contact Dr. Clay Sherrod for his Supercharge "Tune-up" service.
I have a hunch that the rocking in RA that I get after the clutch plates are tight is due to the poor tolerance between the transverse slot on the lower clutch plate and the mating transverse key on the driven shaft that allows some 3 of movement. I have attached a photo showing the parts I refer to. I have removed the lower clutch plate and plan to machine a new one with a slot to closely match the key on the shaft. I will let you know if this solves the problem.
And an update:
I am pleased to report that the RA rocking slop of 3 has all but gone with the new clutch plate fitted with tighter tolerance slot for the keyed driven shaft. I will now calibrate motors and train the drives and check for overall response and GOTO repeatability over the weekend. Best regards Terry Godfrey Oxford UK
Subject: ETX125 Azimuth lock Sent: Tuesday, November 13, 2007 01:49:33 From: Terry Godfrey (email@example.com) After locking the azimuth drive on my ETX125 AT I can rock the forks back and forwards maybe 3-4 degrees. After further tightening the azimuth clamp, the rocking ceases but I am concerned that I might be over tightening. Removing the telescope base I could see that that with the "usual" azimuth tightening the clutch plates were firmly in contact and when the forks were rocked BOTH clutch plates moved together, i.e there was no slippage. With further tightening of the azimuth clamp the rocking ceased as described earlier. I could find no loose mounting screws or see any play in the worm gearing. Any ideas as to why the rocking of the forks stops with increased locking of the azimuth clamp. Terry GodfreyMike here: If you force the movement by hand then you probably don't have a problem. The locks are friction-style locks, just like car brakes. If you apply car brakes you can still force the car to move. If the telescope moves consistently when using the handcontroller for all movements then it is probably OK.
Thanks for the swift reply. It's not that I "force" the movement; it rocks back and forth a few degrees quite freely in azimuth but the clutch plates are not moving with respect to each other, i.e. not slipping, they move together. Tightening the clamp further stops the rocking but I suspect I might break the plastic azimuth clamp arm if I continue with this brute force!Mike here: Is there any slippage when using the handcontroller? If not, I recommend leaving well-enough-alone for now.
Thanks for the recommendation. I will check this evening when I get home from work.
Subject: ETX Collimation Sent: Friday, November 9, 2007 04:26:42 From: JOHN SABELLA (firstname.lastname@example.org) I wondering what it would take to see if your main mirror is collimated correctly. I see some Google hits on the subject for the ETX125 but when I clicked on the links, I was brought to other discusions. I'm assuming there is a laser colimator which probably attachs to the eyepeice mount. I'm not saying I would perform the actual alignment, but I would like to know what it takes to do the check of the alignment to assure that it is correct? Thanks. JohnMike here: See the "Star Testing and Collimation Tips" section on the Helpful Information: Telescope Tech Tips page. A simple test is to slighly defocus a bright star with the 26mm eyepiece; if the rings of light you see are essentially concentric and circular, the optics are OK. Let the telescope reach "thermal equilibrium" (about 30 minutes for each inch of aperture) before doing the test and check on both sides of "in-focus".
Subject: ETX125 PE Sent: Thursday, November 8, 2007 07:57:48 From: William Ellis (email@example.com) Got one of the first additions of the PE and had some problems with motor faults and uncontrolled slews in Auto Align. Sent it back to Meade and all has been well for last couple of years, but now seem to have the same problems like immediate slew in DEC at power up and almost vertical slew in finding level. When I got it back the first time they had installed the updated software and all seemed well. Any thoughts. I know that this has come up before on your site. Thanks Bill EllisMike here: Check the batteries; low power can cause this. Doing a CALIBRATE MOTOR can sometimes resolve the problem as well. Dirty encoders can sometimes cause it. Also, check the condition of the pins on the AutoStar cable connectors and jacks; they should be clean and not bent sideways or too depressed. Reversing the cable may also cure it.
Tried your suggestions but still had DEC Runaway when I chose Auto Alighn. Talked to Meade and the guy actually told me that the last time I was having the basically same problem they changed the DEC Motor. Thought that I would try to see if I could order one from them and replace it myself but think I'll give them another chance. Appreciate your responses! Bill EllisMike here: Does Easy Align work OK? If so, the LNT might be the source of the problem.
Subject: ETX 125EC Disaster Sent: Wednesday, November 7, 2007 12:38:15 From: Thomas L. Bohan (firstname.lastname@example.org) I knocked over my telescope while it was mounted on the tripod, resulting in both plastic arms breaking off. As far as I can tell, there is no other damage, thought he circuit boards are hanging out. Do you have any suggestions for repair. From perusing your great Website, I gathered that at some point, Meade went to metal for those arms. Mine seem to be completely plastic.--Tom--Peaks Island, MaineMike here: Well, you could mount the ETX OTA on a different mount (see the Helpful Information: Telescope Tech Tips page for lots of ideas), get a used mount, or try to repair the damage yourself (or see if Dr. Clay Sherrod would be willing to do the repair). If you decide to try a repair yourself, the article "Extending the Fork Arms" on the Telescope Tech Tips page may help.
Subject: Observing question / double stars / position angle Sent: Wednesday, November 7, 2007 08:56:58 From: julie clayton (email@example.com) Hope you can clarify my question about position angle... copying this from one of your web pages: 1) The primary star is the "center of a clock;" 2) Due NORTH from that star is "0" degrees and the clock moves clockwise to measure; 3) When you reach due EAST from the primary star (a "3:00 position on the clock") that is 90 degrees; 4) "6:00" on the clock face is due south from the primary and is 180 degrees P.A.; 5) As the clock "rotates" clockwise, we reach WEST at 270 degrees P.A. 6) Back to straight-up north, we are in P.A. 359 to 0 degrees! THe question I have is about due north referred to in item 2: is it 'due north' based on where the primary star appears in my eyepiece, or is 'due north' relative to some other position? Many thanks as always for all of your support.Mike here: North is north along the lines of Right Ascension, which converge at the North (and South) Celestial Pole.
Subject: Telescope accessory maintenance for dummies (like me) Sent: Monday, November 5, 2007 03:42:30 From: Tom Farrell (firstname.lastname@example.org) I enjoyed the climate chart you shared with me recently for that location in Arizona. I'm about determined to go to the desert or the most remote beach I can find. I was looking for some info on your site and not finding it. Perhaps you could post these questions? And if you can advise, that's cool too. Appreciate it. Questions following signature. Tom 1. How to avoid electric focuser lockup? There I am out there getting ready to look at this comment which lit up a million times brighter than it was supposed to, and my electric focuser locks up. Without a tool to remount it, all I can do is pack up and go home. I finally just put my bicycle's multi-tool in my telescope case, so I could do this electric focuser remount in the dark without fear of looking the little L wrench which comes with the focuser but even with this, the mounting screw can still get dropped and lost in the dark. There has to be a way to avoid this, right? Let me describe the lockup problem: If I let the electric focuser go all the way to either end of the focal range the focus screw going all the way in or all the way out (and I don't do this on purpose) the electric focuser's motor is powerful enough to tighten the screw, quite quickly, so that it is locked in place by friction and then reversing the motor only results in grinding the gears of the electric focuser. Nothing but uninstalling the focuser, manually loosening the screw and remounting the focuser can fix this. (Yeah, I know I should be smarter than to let t his happen. When doing an smart-finder calibration and using a local object, this is when I loose track of where in the focal range I am.) It would have been nice if a $100+ focusing device had been built with the mechanical or electronic intelligence to avoid these lockups (where users such as my self lack the intelligence.) Anybody have any tips? 2. Can anybody suggest the RIGHT way to cleanly, neatly cut the foam rubber inside these telescope cases to make needed modifications? Even using the sharpest knives or new razor blades with the lightest and most careful touch, the result is ragged and imprecise . Plain gross really even though functional. I suspect there are custom tools for this kind of work perhaps a wire-saw. I would say a laser or heat-based tool but for there being no burns on the cuts the foam rubber comes with. Who knows? I finally found a way to JUST BARELY fit my ETX 90 PE with its rather tall LNT/SmartFinder unit into Meade's regular ETX 90 aluminum case but only by moving around some of the padding and leaving the scope unlocked on its declination axis, so the tube slumps down and gets the fractions of an inch needed for the to fit in and the entire pressure of the closed case NOT to be concentrated solely on the SmartFinder. For this to work, I had to cut out a section of foam rubber section which closes on top of the scope, to provide full clearance for the top/left-mounted LNT/SmartFinder. I ended up cutting more than was needed just trying to clean up the ragged edges. I was really surprised that this was all it took. I do want to caution anybody who considers trying this that I am still not entirely convinced that this arrangement is long-term not going to warp or even break the LNT/SmartFinder mount. But I grew tired of the telescope living in my bedroom under a big plastic bag, you know. The way I rearranged some of the pads make this work by to refocusing the pressure of the closed case on the scope tube really isn't complicated but I'd have to draw a diagram and will if anybody is interested. HOWEVER, if anybody considers this, do so at your own risk, as I am. Proceed with caution, make sure before you make any foam rubber cuts and store your scope this way that you are TOTALLY CONVINCED it will actually fit in there. I came to this conclusion by removing ALL the foam rubber from bottom and top of case (it isn't glued in), then placing the scope where it normally would sit in there, and then messing around with various ideas till I found that lowering the tube from its declination home position provides the needed clearance for the tube. Then it was a matter of improvising with the provided foam rubber to safely protect the telescope when the case close and carried by its handle, the telescope then on its side, with right facing down and left up fortunate, because none of the telescope's weight then bears on the LNT/SmartFinder assembly. Done right, the SmartFinder is never subjected to any kind of pressure or weight. (Or so it seems thus far.) I just want to clean up the ragged cuts I made. And frankly, I'd like to make some more custom cuts to contain various accessories. So if anybody knows what kind of tool or what kind of technique is used on foam rubber cuts, please tell. (I tried to google but it must be a some kind of family secret or something.)
Subject: Retirement Sent: Sunday, November 4, 2007 11:59:54 From: Joe Walker (email@example.com) Congratulations on your retirement. I hope when I grow up I can do the same!!! The best to you on the move to Arizona. Joe Walker Rochester, NY
Subject: Re: ETX 125 on/off switch failure Sent: Saturday, November 3, 2007 08:55:35 From: keith moore (firstname.lastname@example.org) Mike, the latest news is: I had a friend take the bottom cover off and have a look. Too complicated to proceed further so reassembled, whereupon it then worked OK ! It has continued to work OK. We therefore suspect that the problem is the battery protection switch ,and in future I shall remove the batteries when using an external DC supply. Thanks for your help and thanks for your web site ! Keith
Subject: Ahhhh, RETIREMENT!!!!!! Sent: Friday, November 2, 2007 21:00:57 From: Catherine Derouin (email@example.com) Congratulations on your retirement, Mike!! I envy you!! Keep up the great work on the website!!! Hopefully we'll get to see more and more of your astrophotography!!! Bob Derouin Johnston, RI USAMike here: Many thanks! I hope to get more once we get moved and settled.
Subject: re: ETX125PE will lose appox. 2'30" for evey 6hr of rotation Sent: Wednesday, October 31, 2007 20:07:09 From: richard seymour (firstname.lastname@example.org) First, your method of measuring is similar to what i do, but i remove the "tracking" aspect by using Landmarks, and the Alt/Az readout instead of RA/DEC. And, as Mike said, the external RA scale is ***not** very accurate. Set Targets to Terrestrial (or GoTo a Landmark). If you point at (center) a landmark, note the Alt/Az readout (press [mode] 3 seconds, release, scroll to Alt/Az), and then slew a full 360 degrees in azimuth to re-center the landmark, what does the Alt/Az readout say for azimuth? It -should- return to the starting value. Some conditions have specific numeric faults (one dirty encoder gap causes a precise 350 degree readout for a 360 degree slew). Yours sounds much more subtle. Converting from RA numbers to degrees: 6 hours is 90 degrees, 2.5 RA minutes is (2.5 * 15)= 37.5 arcminutes. 37.5/(90*60)=0.0069444, or a 0.69 % error. Your Autostar allows you to adjust the "gear ratio", which is the number of encoder transitions seen per arcsecond of travel. The default value for the ETX125 is 1.36889 (a) verify that your Az/RA Ratio has that value (b) If it did, then try -changing- the Ratio by 0.69% (i think you want to lower it, so 1.36889 * 0.9930555 = 1.3593838) (c) that should restore accuracy per your test... but i must restate that i think use of the RA scale is inaccurate. It's far better to spin a full 360 degrees and recenter the same target, and use the Autostar's readout to see what it thinks about it. have fun --dick
From: wilcoxg (email@example.com) Thanks for the reply and information, but would like to clear up something, when I first reported the issue I made a error in my reporting, I stated the error was with ever 6hrs of rotation, I ment to state it as "with ever 3 hrs" or 45 degrees of rotation CW or CCW. I get the 2.5 mims of error, which keeps adding up, with each 45 degree of rotation. 2 time the amount I first stated. With this amount of error there had to be a issues with the drive unit, working with my dealer (Chris Reich outstanding gentleman) and talking to Meade support the problem per Meade Support is 1 of 2 things, gear slippage or encorder slippage. At this point Meade has agreeded to "pickup and replacement" of the telescope. Thanks for all the support with my issue and hope some day I can return the favor.. Thanks again Gil Wilcox
...another reason I use "degrees" and "360 degrees" for my testing. There's far less chance of error when making conversions from RA to degrees. (i frequently confuse the 1-to-15 and 1-to-4 ratios (RAminute to arcminute and RAminute to degrees)). Plus, using the full 360 means that the -amount- of the error is maximized. Using only 1/8th of a turn means that you are trying to measure 1/8th the amount of error... and 8*(2.5) is much easier to see and measure accurately. If you still have the scope, I am still curious as to what the full-turn error is. I find it hard to figure out how a "slipping encoder" could produce -exact- and -repetitive- errors across many tests. I would expect "slipping" to introduce more random results. My own vote (at the moment, with no other information except the doubling of the measured error) would be one missing gear tooth in the gear system... and -that- certainly says: return for exchange. good luck with scope number two... --dick
Dick, After reading your reply I to was curious, (still have telescope) so I did the test as you outlined, here is how I setup for the test: 1)set scope up and leveled 2)reset the 497, auto calib motors, zip code, daylight savings yes, model ETX125. 3)checkd RA and AZ precents both 10% 4)Trained both drives using 9.7 mm eyepeice At this point I insured the object was in the center of the eyepiece and than used mode to access the RA readout, and loged the reading. From this point I slewed the scope first CW a full 360 degrees, centered object (still using the 9.7mm) and recorded the new reading. I than slewed the scope CCW 360 degrees and recentered the object than recorded the reading. I did the process rotate CW record, rotate CCW record, 5 more time for a total of 12 readings. The results are in mins and than I converted them to degrees of error. Exp. 42/10.5 42 mins or 10.5 degrees 42x.25=10.5 1) 42/10.5 CW 2)12/2.75 CCW 3)52/13 CW 4)23/5.75 CCW 5)56/14 CW 6)3/.75 CCW 7)20/5 CW 8)15/3.75 CCW 9)33/8.25 CW 10)-11/2.75 CCW 11)17/4.25 CW 12)-27/6.75 CCW You are correct, the error is not the same and is random, with a low of .75 to as high of 14 degrees. PS just got word from Chirs, new scope is on its way.. Gil Wilcox
>At this point I insured the object was in the center of the eyepiece > and than used mode to access the RA readout, and loged the reading. here you made one change (and a -critical-, crippling change) from my suggested approach. You should have tapped the [scroll down] key once to reveal the Alt/Az readout. The RA readout will -change- with time. Even if you just do -nothing- (no slewing), it will be slowly advancing. That is because it is telling you the -sky- coordinates, not the telescope's internal -angular- coordinates. Since the time you take to slew will vary, the RA reading you are seeing will vary (along with its simple by-the-clock advancement). ... >You are correct, the error is not the same and is random, > with a low of .75 to as high of 14 degrees. Since the system you were using to get numbers was using a moving target, the results do not really tell us anything that we can make absolute statements about. If you still have the scope, please try again with the Alt/Az readout. (testing really is much harder than it looks at times...) have fun --dick
And from earlier:
From: firstname.lastname@example.org (email@example.com) Have you tried Calibrating Sensors? The procedure provides a fine correction to compensate for small differences between the physical orientation of the sensors in the LNT module and the optical axis of the scope. When a GOTO requires a large slew, the small errors can add up. Also, the accuracy of the lat/lon for your location can have an effect. If your zipcode covers a relatively large area, the preset values provided by the Autostar may be off slightly from your actual position. If you have access to a GPS, you can edit your location with precise values. Google Earth can also sometimes be useful. Regards, Mike Hogan
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