Last updated: 31 December 2006
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: Can I repair the dec gear or find another one Sent: Friday, December 29, 2006 19:10:59 From: JOSEPH CAMERON (email@example.com) My dec gear is not turning. The motor on it works good but not the gear itself. I have an LXD75. Thanks, Joe Cameron in Prescott, AZMike here: Have you opened the inspection port in the DEC motor housing to check the gear itself? It sounds as though the setscrew might have worked loose. Check the "LXD55 / LXD75 Information" section on my LXD55/75 Site for more information.
Subject: LXD75 manual Sent: Wednesday, December 27, 2006 12:46:13 From: Frans Franssen (firstname.lastname@example.org) can you tell me if the three volumes LXD 55 tips and tricks also apply to the LXD 75 series from Meade? Thanks for your reaction. FransMike here: Much of it is still useful for the LXD75 models. Anything that is specific to the LXD55 mount head/tripod may or may not.
Subject: Re: LXD75 Mount Sent: Friday, December 1, 2006 10:29:13 From: thomas robison (email@example.com) Season's Greetings, Mike! Was interested to know your impressions on the ability of the LXD75 mount for astrophotography. I am getting ready to dip my foot in that realm and would appreciate any light you can shed on this mount. I really like reading about your trips to Oracle and your diary/observations. Take Care, TomMike here: Depending on what type of astrophotography you plan, the LXD75 can be an excellent mount. Of course, it doesn't compare to a LX200 mount but then it costs way less!
I think there's an LXD75 in my future. It would be awfully hard to beat without spending a lot more $$. Happy viewing! Tom
Subject: LXD75 RA fault Sent: Thursday, November 30, 2006 11:49:03 From: firstname.lastname@example.org I found it very funny (and great) that you also have this LXD75 site. I have an ETX and I you have posted some of my photos and answered some of my questions before. Great, great work!!! We love you!!! Bad news though... I bought a 6'' Newt LDX75 today... She was all set up grand this morning. Balanced, calibrated, I had even got around to training the drive. I was doing a few (daytime) go-to's when suddenly the DEC drive 'slipped' and it started slewing off on its own ...stop-go-stop-go then nothing. Horror! I did a 'reset' on the autostar and 'calibrate motors', the RA is fine but then it just reads: MOTOR UNIT FAULT. There is no obstruction, it's balanced perfectly, and the battery is full and all cables are ok. I rang MEADE in Germany and I got a very vague ''we will email you a solution'' ''Motor unit fault in DEC motors'' I was very carefull to take my time in setting this scope up as I had a few days of torture with the ETX. I removed the cover on the Drive unit and the encoder wheel looks fine, no blobs of grease or any obstructions. I did however notice the housing for the screw that holds the cover in place is literally rubbing off one of the cogs. It has even left a circular mark on the wheel and it's a little worn. I tried the other autostar handbox on the unit also Just in case it was an issue with the unit or cable. I reset it and set it up for the LXD75. This time I got as far as 3 star alignment' and then the same meggage again. I think the firmware 'locks' the autostar when it gets an error like that and then when you start it again it automatically does a calibrate motors and will not allow you to bypass it unless the motors check out. I juess it's to avoid any further potental damage. I am at a loss! Any help would be VERY much appreciated. Kind Regards, Frank.Mike here: When you checked the DEC gears, did you try to run the drive with the cover off to see if both gears actually turn? I suspect that isn't the problem but you could check. However, the source of the problem MIGHT be in the DEC cable connector that plugs into the jack on the GEM control panel. Check the condition of the pins, both inside the jack and on the connector; they should not be bent sideways nor too depressed.
Subject: LXD 75 Mount One Star True North Sent: Wednesday, November 29, 2006 10:26:08 From: Gregory Kaiser (GKaiser@rfmd.com) Was wondering How a one star alignment followed by an iterative Goto from Vega to Polaris physically adjusting the mount each time for Polaris to center it, usually after only 3 times with my mount guarantees a good alignment even for Guiding and Imaging For exposures to 5 minutes. Since true north is 55 arsec from Polaris , how does this work out. It seems to. I tested it with Polar Scope + Calendar and clock on the mount . Polaris was centered in the eyelet at the current date and time I tested it.. It would seem that it would be off 55arsec from the center. Greg Gilbert, Az.
From: richard seymour (email@example.com) The simplest answer to "how does it work?" is that the Autostar knows how far Polaris is from the true pole (and it's 45 arcminutes, not 55 arcseconds, away). So if you tell the Autostar to GoTo Polaris, and then mechanically adjust the mount to improve its pointing at Polaris, you are, by doing so, also adjusting/affecting the mount's accuracy in alignment to the -pole- at the same time. It's as if you had a stick 6 inches long, and two paint spots on the wall spaced 6 inches apart horizontally. Call the right wall-spot "Polaris" and the left spot "Pole" Now "adjust" your stick so that the right end is "on" Polaris. When the stick is parallel to the floor, with the right end at "Polaris", then the left end will be found to be very, very close to "the pole". That's what's happening. have fun --dick
Thanks Dick, I think I understand now. When you say "Autostar knows how far Polaris is from the true pole" Does this mean the offset is calculated in to the Tracking as well as GOTO Or just the GOTO function. Since Autostar knows the date , time long. and lat. as well I can see now how it works. The other night I did a One star followed by several Goto's from Vega to Polaris And after the 3rd attempt adjusting the mount after each iteration at Polaris the final Goto from Vega to Polaris was dead center. I then checked the clock and calendar on the mount And adjusted the RA to match the current date and time and Polaris was almost dead center In the circlet Thanks again Mike for the Forward Greg
>When you say "Autostar knows how far Polaris is from the true pole" >Does this mean the offset is calculated in to the Tracking as well as >GOTO >Or just the GOTO function. Since Autostar knows the date , time long. >and lat. as well I can see now how it works. The Tracking expects/trusts you to have the mechanical RA axis pointed -at- the pole. Thus "tracking" merely involves rotating that axis to follow the stars. The DEC motor is not used in Polar tracking. This is how all pre-computer telescopes did it: a fixed-speed motor driving only the RA axis. After physical alignment, you'd unclamp the RA, point at your target, then clamp to "engage" the tracking motor. For the next target, you'd unclamp again and repeat. In the Autostar, the alignment process tells the Autostar where the stars are with relation to the motor encoders. Polaris' offset is taken into account during the process, and therefore does affect later GoTo operations. At the risk of totally confusing you, i could say that "Tracking" only requires -mechanical- alignment. You don't have to "align" the Autostar at all. GoTo's require -Autostar- (logical) alignments. If you use the Two Star (or Three Star) alignment technique, and -don't- follow it with the iterative Polaris/Vega sequence, you could have good GoTo's (since the Autostar has been "shown the sky"), but relatively poor tracking, since you may not have the RA Axis accurately aligned to the pole. have fun --dick
Subject: re: Beginner Problem Sent: Monday, November 27, 2006 19:41:38 From: richard seymour (firstname.lastname@example.org) Your symptoms (it says it's slewing, yet it's not moving) are most commonly caused by simply not tapping [enter] before tapping [goto]. This is -especially- true with the Planets. What's happening is that failing to tap [enter] means that you really have NOT fully selected a new target. So when you tap [GoTo], it Goes To the -previous- target, which is probably where you're already at. Hence: it says "slewing", but no apparent motion happens, since it's going to its current position. have fun --dick
Subject: Stiff RA Axis Sent: Tuesday, November 28, 2006 02:01:45 From: Frank J Mraz (email@example.com) Why the weight ? I wanted the RA axis to swing downward indicating a "loose" enough RA. It didn't move at all. Frank P.S. I changed the "Subject". Thanks for the reminder....
Subject: Stiff LXD55 Sent: Monday, November 27, 2006 21:09:14 From: Steve (firstname.lastname@example.org) When I did the hyper tune on my mount, I found that both the RA and DEC gears were very snug, in fact overly snug, in their housings. They are really just fat aluminum cylinders with gear teeth machined into one end. I cleaned all the gunk off and sanded them with several grades of wet or dry sandpaper, starting with 240 and ending up with 600. then cleaned again and polished with polishing compound until they were beautifully shiny. They really are a beautiful piece of metal when you get then all clean and done up. Then you do a similar treatment to the insides of the housings. When you get done, they will actually spin a bit in the housings with no grease, but you have to be careful taking then in and out, as they can get slightly cocked sideways and lock up to the point where they are difficult to take back apart. Reassemble with some good white grease, and you are gonna think you just rebuilt a Porsche transmission, well maybe that's a bit of an exaggeration, and I don't know if that would help Frank, but it sure helped my mount.
Subject: Techtips Sent: Saturday, November 25, 2006 16:14:50 From: Frank J Mraz (email@example.com) In your "LXD55 Technical Tips", you covered problems with a slipped RA gear. I checked mine as per your Tech Tip pages and did not find a problem, BUT my RA axis is still very stiff. This is a pre-owned LXD55 SN-10. What do you suggest ? FrankMike here: Do you know if the previous owner made any modifications to the mount, like removing/changing the lubrication? If the problem is with the gearbox, you might check the article "LXD55/75 Gear Box Maintanence"; perhaps that will help you. Does the stiffness occur with or without the axis lock engaged?
The previous is no longer alive...Sorry...He/She can't help us here. The gearbox isn't the problem as I removed it as per your instructions. The axis still turns stiffly. Stiffness occurs while axis lock is off. While on, I can never tell if the telescope is in or out of balance...Another problem.Mike here: Balance should be checked with the axis unlocked, not locked. Is the stiffness in just one location or throughout the entire movement of the RA axis? It could be that some lubrication is required or it could be that bolt that holds the RA mount together is too tight. I'm away from home now (and the LXD55 is boxed up anyway) so can't check mine.
The stiffiness is really only felt while UNLOCKED. When in the locked position, I can't tell if it is tight or not for the motor. Yes...Balancing ONLY when unlocked. How do I release that bolt that keeps the RA so tight?Mike here: As I said, I can't get to mine right now (I'm away and it is boxed up in the garage). But in looking at the photos from my article on the slipped RA gear, it appears there are likely two bolts on either side of the axis. These would appear to hold the mounting head to the mount itself. With the telescope and counterweight rod removed you could check those out. You might have to remove them to get at the bolt that holds turning portion.
Subject: Beginner Problem Sent: Thursday, November 23, 2006 04:22:21 From: Frank Mraz (firstname.lastname@example.org) I recently purchased a preowned LXD55 SN10 and while testing it, one thing seemed to be happening and I have no idea why. These are the facts...Put all necessary inputs (including quiet slew) and used easy align. Everything went fine during the align. Slewed to Mercury and Venus...still fine. Slewed to Jupiter, the handset showed moving, but no motors ran. Pressed mode and changed quiet slew to off. Tried Jupiter again and this time it slewed fine. What's happening ?Mike here: Did you do a CALIBRATE MOTOR and TRAIN DRIVES?
Yes, I did. Thank you...FrankMike here: Could have been just a temporary glitch. If it doesn't happen again then don't worry about it.
I am very certain it is due to an off-balance situation, BUT, I can't find that sweet spot because the RA axis is not loose enough.Mike here: Things would have to be pretty far out of balance for there to be no slewing. Could you have overtightened the axis lock? It should be easy to repeat the steps you first described and see if it happens again.
I bought the telescope AS IS. I need to start from scratch. FrankMike here: OK. Read the manual, three times. Then work with the telescope indoors until you understand how to operate it and WHAT it should be doing. Then you can go outside in tha dark and start using the telescope without the frustrations of trying to learn the telescope in the dark.
You mis-read my post. I have used the telescope MANY times and find that the RA axis is stiff and balancing is really impossible. Without the scope (but with the cradle) and just one weight, the mounting will show driving problems until the weight is very near the bottom near the tripod. I believe that the previous owner did some work on it and "perhaps" tightened the RA shaft. How to loosen it (or adjust it) is unknown to me. This was my original request. FrankMike here: Sorry, I was going on the Subject of your email. Without the scope mounted you shouldn't have the counterweight attached either. That will give an invalid balance condition. As to loosening the bolt, my LXD55 GEM head is still boxed up in the garage. Perhaps someone will respond to this posting.
Subject: LXD55 SN10 Sent: Sunday, November 19, 2006 04:37:57 From: Frank Mraz (email@example.com) I just purchased a used Meade LXD55 SN10 from a friend and I want to "upgrade" it to the level of the LXD75....Things like the 8x50 finder instead of the 6x30. Any sugggestions ? FrankMike here: You can replace the finderscope with other models and you can get the LXD75 tripod by itself.
Subject: LXD75 Mount Sent: Saturday, November 18, 2006 20:36:19 From: thomas robison (firstname.lastname@example.org) Quick question: Do you personally think the LXD mount is excessively noisy? And, at the retail price of $599, do you think it's a real value? Thanks, Tom Robison Seattle, WaMike here: The LXD75 mount is WAY better than the LXD55 mount. In comparison with similar mounts, it is appropriately priced. As to sound levels, in comparison to what? Certainly there is sound coming from it, especially at faster slewing speeds. But then even the WIYN 3.5m telescope makes noise when slewing. If you want a quieter (slower) slewing, you can set the AutoStar to "Quiet Slew".
Thanks for your reply. Guess I should have said whether it was loud enough to annoy neighbors late at night from the backyard. Also, can I use my Autostar hand controller from my ETX-125 interchangeably with an mount such as the LDX75? Or would this mess with the settings I have for the ETX which was supercharged by Dr. Clay? Thanks, again! I also looked at your picts from your trip this summer. Some really nice photos! As you well experienced, we had an incredibly beautiful, dry summer here in Seattle. TomMike here: That will depend on how close your neighbors are and whether they have their windows open. Invite them over to show them the sights through your telescope and maybe they will complain less. But the LXD is not silent so if they want silence and you want the LXD75 one of you will have to move. Yes, you can swap the AutoStar #497 between the ETX and LXD but you will have to reselect the telescope model, CALIBRATE MOTOR, and TRAIN DRIVES each time you do. And you should have the latest version of the AutoStar software installed. So, yes, you will change Dr. Clay's settings.
Subject: ETX 90 on LXD 8SC Sent: Monday, November 13, 2006 21:32:17 From: James Benet (email@example.com) saw your oracle observatory report page and wanted to ask you something: What adapter did you use to mount the 90 ETX tube to the 8" SC OTA? Im planning on getting that LXD telescopse since I have a spare 90 ETX OTA and wanted to mount it exactly as you did. I see that you added foam to make it stable. Im thinking you used the Meade Piggyback mount for 7-8" SC for it but not exactly sure. Im in love with that scope can you tell me how you like it? this one: http://www.telescopes.com/products/meade-piggyback-bracket-for-7-inches-and-8-inches-12198.html Im ordering from outside the US so that is why I have to be very precise as there is no return. Thank you for your help and your great sites. JamesMike here: I use the Meade Piggyback Bracket, model #07394, for piggybacking my Nikon D70 DSLR or ETX-90RA OTA or PST on the 8"SC. Works OK except for optical axis alignment; as you noted I need to add something to raise the ETX OTA. This is less an issue with a piggybacked camera and no issue (for me) when attaching the Personal Solar Telescope as I have no solar filter for the 8"SC that would allow to me to simultaneously view the Sun through the 8"SC.
Subject: Correct Balancing of LXD75 Mount Sent: Saturday, November 11, 2006 18:29:00 From: Dennis O'Hara (firstname.lastname@example.org) I am very new to equatorial mounts and goto mounts, i had a 4 inch refractor on alt azimuth for years and decided to go computerised, SO now i have a Meade LX50 OTA mounted on Meade LXD75 with Autostar using the mounting bracket. Attached to the scope is a telrad and 8 by 50 finderscope, my question it seems you cannot get an exact balance of the scope if it is good on one side of the mount, it is top heavy or whatever on the other, so i guess you just go for the mean, is that right ? amd when you use the autostar you have the RA and DEC clamped so all would be ok.??. if there is detailed info on setting the scope up correctly in dummies terms i would appreciated it, i am in Toowomba Qld. Australia.. Cheers MateMike here: Ideally you should be able to balance in both axes in all orientations. However, as you have noted, practically that is difficult to achieve with the supplied single counterweight rod. Depending on the accessories you add and their position, precise balance corrections will change and unless you add additional counterweight systems you will not be able to achieve 100% perfection. That said, unless the accessories you add are extremely heavy you normally won't have any problem if you get as precisely balanced as you can.
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