Last updated: 30 September 2007
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Last updated: 30 September 2007 |
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This page is for user comments and information of a general nature or items applicable to all LXD55 and LXD75 models. 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: LXD55 bad slews Sent: Monday, September 24, 2007 10:59:38 From: robert (astroram@comcast.net) I have a bit of a problem with my LXd55 mount and wondering if you might have a suggestion or two. I recently updated to 43Eg and now my Deep sky object GOTO slews are 20+degrees off? The first 2alignment stars where just within my FOV of the finderscope when doing a 2 star alignment. Trying a three star hoping itwould be more accurate, my third alignment star slew was about 20 degrees off , the star was altair and it was 20 degrees west/south west of Altair? Even after centering the 3rd alignment star (ALTAIR), my subsequent gotos were again about 15 to 20 degrees off. In fact I tried to goto to M27 and the scope ended up pointing closer to Deneb. Any suggestions? BTW I did try a menu reset,recalibrate the motors, and also retrained the drives. The scope tracks well also if that is any help.Thanks so much for your time. BTW I have 2 autostars and both exhibited the same phenomena on this mount. Thanks Bob MidiriMike here: Since the problem occurred after the update AND since the offset is about 15 degrees (or one hour), have you checked your Site parameters and the time (including Daylight Savings) settings?
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Yes I did Mike, Its yes for daylight savings. Re-entered my site info, its easy since it asks for zipcode now. The thing that gets me is the fact that the first 2 alignment stars are within the finders FOV, and the third star is way out. Its picked Arcturus/Vega/ then Altair at roughly 8pm at night. Thanks BobMike here: I have never had good results with ZIPCODE so I use a nearby city or actual location lat/long. Try that.
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Thanks Mike, but that did not work either. I tried another reset, then tried to align, but without being able to retrain the drives, I was gettin alignment failures, it was now picking Vega as an alignment star, then when it finished slewing, it was closer to altair. Now I am really confused. The times are correct, the site is correct, dont know what else to try. thanks BobMike here: Perhaps the download was bad. You could try this: if you are loading the ROM into the AutoStar via Meade's web site, instead download the ROM file directly and place it in the Ephemerides folder, then install the update to the AutoStar using the downloaded file. Don't forget to CALIBRATE MOTOR and TRAIN DRIVES after the download.
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I have two autostars and two LXD55 mounts. This autostar works fine on my other mount, so I really dont think its the autostar. Something is amiss with the mount I think. I forgot to mention this. Just to double check, My other mounts autostar after training the drives, acted the same way with the bad slews the night before. BobMike here: OK, so based on this it sounds like the mount has the problem. Have you checked the gears for slippage on their shafts?
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No, I wanted to exhaust all other non invasive measures first. I will have to do that next week as Tuesday I go back to night work for 7 straight nights of 11 and 12 hour shifts. I wont be able to tackle this now till next tuesday. Do you know any sights that have diagramitics of the insides so I won't mess anything up? Or any sites that have guides on doing this. Thanks so much for your time Mike. Bob MidiriMike here: Well, it may not be that "invasive". Just pop off the gear housing covers on the mount and have a look. See the article "LXD55 / LXD75 Information: Fixing a Slipped RA Gear" for some more information.
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Thanks for your assitence, Mike. Clear skies Bob Midiri. I will let you know next week how I made out.
Subject: Guider Relays and LXD75 Mount Sent: Saturday, September 22, 2007 06:24:25 From: fabrizio piermaria (fabrizio.piermaria@email.it) hi,i'have a lxd75 and i will want to know the connection scheme for connecting the apm 909 to port module?and for autoguiding whit 909 i will update autostar firmware? in my autoguiding session i use a slowest(default) speed present in autostar,can i use custom guiding example 0.50x (lower) for guiding? thanks fabrizio piermariaMike here: The APM909 (which I don't think has been certified for use with any telescope but the LX90) would connect to the AUX port. If it is recognized it may establish its own guiding speed. Let me know your results.
Subject: Dec worm gear play Sent: Sunday, September 16, 2007 03:21:43 From: keith morris (keith@morrisgifts.co.uk) I have a Meade LXD75 and through an accident I have had to replace the Dec motor. When I had the old one off I noticed a little bit of sloppy movement in the silver cog. I started to adjust the 3 allen bolts but I am not sure how tight the worm drive should be. Should I be able to turn the silver cog and drive the dec by hand easily, very hard or not at all? I have my motors on quite slew mode and while the RA is quiet, the dec is as noisy as when in fast or normal slew mode. I don't know if training the new drive will make this quieter, I thought I would get your advice before proceeding any further in case of damage to my mount, worm gears or new motor drive unit. Living in the UK prices are not cheap here, I paid approx $140 for a new dec motor. Looking forward to your reply Keith Morris United KingdomMike here: With no weight (ie, no telescope mounted) you should be able to turn the gear by hand. Also, there should be no movement of the gearbox so check that all is secure.
Subject: Meade RA and Dec Drive Motors Sent: Saturday, September 15, 2007 21:17:58 From: K. Walker (kman93553@verizon.net) Where might I find replacement motors for my LXD75 and LXD55 mounts? Any idea what might be the going rate on a set of motors other than new? Thanks, Ken Clear Skies, Keep Looking Up! Clear Sky Alarm Clock Lancaster, C.A. website: www.kmanskies.8m.netMike here: Have you tried Telescope Warehouse? The link is http://www.telescope-warehouse.com/. I haven't priced them.
Subject: re: LXD 75 Sent: Saturday, September 15, 2007 13:54:05 From: richard seymour (rseymour@wolfenet.com) You wrote: > I did find 3 star worked better for more accurate goto but it > often selects stars that are obscured by obstacles at my viewing > location so I have stuck with 2-star. Whenever an alignment process chooses an inappropriate star, just tap the [scroll down] key, and it will choose another one. (yes, there are times when -none- of them are suitable, but usually you can compromise). have fun --dick
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From: Howard Nielsen (howardnielsen@rbrm-law.com) Well, after trying all the suggsestions over the last few days, I am throwing in the towel on this mount and I remounted my 8" scope on my old fork mount. I got pretty go goto function on the autostar, but once I get the object, it still will not track the object no matter what I do. I am familiar with autostar as I have owned an ETX for many years which works great. I purchased the LXD 75 to give me more observing time with my larger scope which was not goto, but it has ended up taking an inordinate amount of time fiddling with the mecahnics. I am thinking I will have better results if I step up to the Vixen Sphinx; more money but I guess one gets what they pay for. I appreciated your advice and your great websites. Thanks for the efforts.Mike here: The German Equatorial Mount (same as many Vixen models) is more complex to use and get used to.
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I found a note from someone who had the same problem on the yahoo group site; severe RA drift. He found the bolts that hold the RA worm gear were loose and binding when the mount was in tracking speed. The mount still slewed fine but just did not track, exactly my problem. I will have to do an autopsy and see if I have a similar problem.
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Well, I tried something else first based on what the Meade representative told me when I got through. He advised me to get the mount roughly polar aligned, turn on the autostar, enter the date but do not enter the time and do not advise it if it is daylight saving or not (apparenlty it will pick all this up from my zip code entry per the Meade representative), then go to "mode", then go to "targets", then slew to a star, then set it to "astronomical," and then check and see if it is tracking. I did this and let it sit for 15 mintues and my selected star was still dead center ! Then I went into the 2 star align procedure and everything seems to be working now. All very inscrutable but I will not complain. Thanks again for the advice and encouragement not to give up on it.Mike here: The ZIPCODE only sets the location and GMT offset and not the current local time (and I doubt that it now sets DST on/off appropriately). However, if you have correctly aligned the GEM polar axis (and the telescope optics are aligned to the polar axis) then it will track the sky motion as that is what a GEM does. But glad to hear that all is well.
Subject: LXD75 Drive Electronic parts? Sent: Wednesday, September 12, 2007 11:16:28 From: Craig Combes (craigc@hawaiiantel.net) Thank you very much for your efforts! Do you happen to know where I can get replacement parts for LXD55/75 driver boards; specifically the optical encoder receiver? Do you know of anyone but Meade that might have boards that are defective and might be available for parts? I've posted numerous "Wanted" ads around, but so far, no luck! Thanks for any help you can provide! Craig CombesMike here: Have you tried Telescope Warehouse?
Subject: LXD 75 Sent: Wednesday, September 12, 2007 08:23:19 From: Howard Nielsen (howardnielsen@rbrm-law.com) I purchased an LXD 75 mount from Opt a few months back. When I powered it up, I immediatly got an electrical short. I sent it back to Meade for repair. After it was returned, I was able to get the GOTO functining fairly well, but the mount will not track an object no matter what power source I use. It is set to Sidereal rate and I have tried to track by just using the "Targets" and "Astronomical" function but no dice. The motors work as the mount slews find.Meade did update Autostar when it had it. I still tend to think it is an Autostar issue, not a mechanical one. I have emailed Meade by no response. I am thinking of sending it in for a tuneup but before I spend $250 I thought I would see if you have any tips. Thanks a lot. Howard Nielsen. javaman@qwickconnect.netMike here: Have you done a CALIBRATE MOTOR and TRAIN DRIVES (on both axes)? What alignment modes have you tried?
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Yes, I calibrate on each use and have trained both axis drives several times. I have been using 2 star alignment. I did find 3 star worked better for more accurate goto but it often selects stars that are obscured by obstacles at my viewing location so I have stuck with 2-star. Howard.Mike here: Are you selecting stars that are at least 90 degrees apart and near or on the celestial equator? Selecting stars that are too close together or at high declinations will result in less accurate alignments.
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That may be a problem. I have not been doing that. Any other thoughts on why it will not track once an object is centered? Thanks again for this help.Mike here: Can you see Polaris from your location? If so, do a One Star alignment to align the polar axis. Then do an Easy Align. That's what I do most times when at Oracle Observatory with my LXD75-8"SC. It could also be that you need to align the optical axis with the polar axis; see the manual for more information.
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Thanks for the assistance Mike.
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