Last updated: 31 May 2003
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Last updated: 31 May 2003 |
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Subject: Bent Encoder Revisited Sent: Saturday, May 31, 2003 16:09:02 From: StarManGMH@aol.com Just wanted to let you know I received my $75.00 order from Meade. They sent the whole motor, covers, and coil cord. Pretty cool considering I thought I was paying for just the encoder wheel itself. I haven't had time to put it on yet but it shouldn't be too hard with everything all together. Thanks again for the help you gave me. Gary Hatfield Thaxton, VA
Subject: LXD 55 go to/slewing problems Sent: Saturday, May 31, 2003 10:39:40 From: Gailwov@aol.com Unfortunately, I lost your last response to me but I recall that you said something about gear slippage. I did find the gold gear loose on RA, also noticed a little "play" in the silver gear on both axis but set screws are tight so I'm assuming this is ok. Does that sound ok to you? I'm gonna give it another try at my first clear opportunity to see if things are any better. Only other suggestion you had was to download new software which I haven't done at this point. Thanks for your help. Warren Vaughan Williamsburg, VAMike here: The setscrew could be "tight" but the gear might still slip if the setscrew is not against the flat side of the shaft.
Subject: LXD55, align with Compass Sent: Thursday, May 29, 2003 19:14:41 From: Russell Gibbons (rgibbons@marvell.com) I had tried to align with a compass, but found it inaccurate. Large pieces of metal and the motor magnet can shift the needle, Also magnetic north is several degrees from true north, and moves every year. (You can find the offset from magnetic north at: www.geolab.nrcan.gc.ca/geomag/mirp_e.shtml) I ended up mounting a compass to the scope, doing a polar alignment, then made a permanent marking on the compass over the needle while aligned. (The air bubble in a cheap compass can be used to level the scope in a pinch.) Note on 3rd party power supplies and batteries: Don't use the thin wire that Meade has on the battery pack, It is too resistive for the large current needed at fast slew rates. Using a thicker wire allows the scope to slew about 30% faster. Russ GibbonsMike here: Yep, Magnetic North may be different from True North by up to almost 20 degrees and is also susceptible to influences from other sources.
Subject: Polar Alignment of LXD-55 Mount Sent: Thursday, May 29, 2003 09:12:07 From: SJC@pwlaw.com (Steven Christiansen) I own a Meade ETX and LX200 scope and have always enjoyed your site. I recently purchased a Meade LXD-55 scope and mount. I understand there is a "step-by-step" list posted on your site on how to best get a good alignment of the LXD-55 mount. Can your tell me if such a list exists and how to find this list on your site? Thanks, Steve C. Steven J. Christiansen Salt Lake City, UTMike here: The instructions on the ETX Site are for the ETX models. Check the LXD55 Information section on my LXD55 Site.
Subject: Tripod Knob
Sent: Wednesday, May 28, 2003 17:36:45
From: Thomas Rutherford (rutherfordt@earthlink.net)
Do you (or anyone else) know the thread pitch of the black plastic
"knob" which holds the triangular tray to the LXD tripod? I have
managed to misplace mine and would like to try to find a replacement
locally instead of going through Meade.
Thanks.
Tom Rutherford
Mike here: Meade might send you one for free; couldn't hurt to ask.
Subject: LXD55 10SN alignment/slewing problems Sent: Wednesday, May 28, 2003 07:30:35 From: Gailwov@aol.com Recently I read with interest John Goodman's problems which happen to be very similar to mine. John and I exchanged notes and I now see that he's on the way to a solution, hopefully. Here's the deal with me. . . received my scope in January and early on had successful 2-star alignments but lousy go-tos. Later, for some unexplained reason couldn't get successful 2-stars. Most recently have gone to one-star alignments using Arcturus and had the scope slew to or below the horizon. When I slew back to Arcturus, do a sync, and do a go-to someplace else I get the slewing message but nothing happens. I've done the train, calibrate, even the reset at one point but to no avail. Also begin each session by leveling and aligning to Polaris. . . having it in the center of the 26mm field of view. I've got about 45 years of amateur astronomy under my belt so I'm not clueless. . . or I didn't think so. This thing is so far off that it leads me to believe that I've got more serious software or drive problems. Any suggestions before I throw in the towel? Warren Vaughan Williamsburg, VAMike here: Your comment about no slewing occurring when doing a GOTO following a SYNC concerns me. It sounds like you may be experiencing some gear slippage. Is the "no slew" in only one axis or both? You might want to check the gears.
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After I complete a one star alignment, then select something, hit enter, then go-to I get a "slewing" read out with no motion, no sound, on either axis. Love your web-sit but I'm so full of tips, many that I've tried with no success, that I really getting frustrated with this thing.Mike here: I presume the telescope slews during the alignment process and that you press ENTER once you have centered the alignment star(s). Have you tried updating to the current Autostar version from Meade's site (2.6Ed). Not that there is a bug fix for what you are experiencing but the just loading the new version might fix the problem if the problem is within the Autostar.
Subject: LXD 55 SC 8" Sent: Wednesday, May 28, 2003 08:13:46 From: Javier Villarreal Nuez (JVILLARREALP@gruma.com) I read your site about the percetages adjustments and did some changes yesterday. I first put 17% on the R.A and didn't get a diference (i calibrated after each change) and the went up to 50% with no apparent change in response, i even tried 99% without response on the "1" and very little (with very long waits) on "2" speed. Do you know what can be wrong?. I was using a terrestrial object and high power (10mm recticle eyepiece with 2X barlow). Maybe the object was in a position where the telescope was way out of balance or something. Do you recommend that i do this with a celestial object?. Have you done this with your LXD55 SC8" ?. Thanks for all your help. Javier Villarreal PS: I changes both axes in case i was changing the wrong one.Mike here: Personally I have not had a need to change the percentages on either any of my ETX telescopes or the LXD55-8"SC. I'm somewhat surprised that you didn't see any change. I would hope that the telescope was not so out of balance that the movement would have been affected.
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Thank you Mike !!!. I'll try tonight again using celestial objects and let you know. It would be a good advise maybe not to use certain objects to adjust percentages. ... Have a great day Javier ...
Subject: Polar alignment of lxd 55 sc Sent: Sunday, May 25, 2003 09:29:34 From: "Neil Sinclair" (neil.sinclair3@ntlworld.com) I have read through your problems and found that Dick Seymour (email 10 May) is having similar problems to myself. I have taken the scope out aligned the starleg to north via a compass. I live inBelfastso latitude is 53 - 54 degrees north. I have made sure the tripod is level. I dial in 54 degrees in the latitude dial. When I look through the polar alignment finder Polaris is not even close. I have to raise my lat to about 75 degrees to get polaris within the FOV. What should my RA and Dec setting circles be set at? Is there anything else I should be doing while setting up. Thanks Neil SinclairMike here: If the tripod is level and the telescope is pointed at Polaris when in the GEM Polar Home position, then you have the proper set up regardless of what the tripod latitude scale shows. Don't worry about what the setting circles show if you plan to use the Autostar. As long as the RA rotational axis of the GEM head is parallel to the Earth's axis, you are OK. That means it would be horizontal at the Earth's equator and pointed straight up at the North Pole. As Dick pointed out, the telescope optical axis should also be parallel to the RA axis. If you have problems with the setup, remove the OTA and practice setting up the tripod/GEM in the right Polar Home position. Once you get comfortable aligning the GEM head to Polaris, then you can remount the OTA.
Subject: Hi there !!! Sent: Friday, May 23, 2003 08:29:52 From: Javier Villarreal Nuez (JVILLARREALP@gruma.com) I have the exact same telescope you have, i think it is the best combination for the LXD55 mount !!. I have a little question for you, it is normal that when you slew towars one direction and then change to another it takes time to respond ?, mine does. You have to keep pressing the arrow key for a little while and then it starts moving. Is it normal or is there something loose inside the gear?. It takes longer to respond if you use "3" or "4" speed buttons but actually it happens on all. It becomes a little frustrating when centering an object because you keep pressing and suddently it moves too much and you get past the point you wanted. Also, taking the opportunity if not too much to ask: Is there a way to manually guide a long exposure astrophoto on the LXD55 ?. I noticed that when you move the telescope with the arrows it deactivates the tracking for a little and then when you release the arrow it takes a little to recover the R.A tracking. Maybe that is kind of like the same problem i have above. Thank you for you web page, excellent information !!! Best regards Javier ..Mike here: Yes, the two are related. Check out the "percentage" articles on the Autostar Information page on my ETX Site. By fine-tuning these values you can adjust the amount of delay.
Subject: LXD55 Sent: Wednesday, May 21, 2003 13:19:21 From: "Dave" (david.godley@btinternet.com) Hi Mike, glad to see you are supporting the LXD55SC.... I received mine yesterday but persistance cloud in the S.E of England means it hasn't seen 1st light yet! Having just read thro' when you 1st received yoursMike here: They finally admitted it was an "optional" part.I found the same part, 2" fitting missing as well........ before I hassle my local importer, did you ever get to the bottom of whether it was supplied or not? Did they send you one? Buy the way, I too purchased a new ETX125 UHTC and eye piece set on 1st of February, afterspendinga lot of time with a 90. Clear skies Dave
Subject: Update Sent: Tuesday, May 20, 2003 14:31:52 From: "John K. Goodman" (jgoodman@rhythm.com) Hi Mike, Well after I mentioned your name regarding my LXD55 problems, they very very accomodating indeed, and immediately sent me a new DEC motor. Initiall I see a huge improvement. GOTO's are much better, although not perfect. However I believe I am experiencing "rubber-banding". When i try to fine-tune a GOTO using the Autostar buttons, after I let go of the button the motor creeps back down in the opposite direction for a few seconds. Is this rubber-banding? Should I re-calibrate and re-align? thats what Ive read so far as the best solution..... anyway, thanks again for all your help! -- _____________________________________________ John K. Goodman - Character Animator/TD Rhythm & Hues Studios - Los Angeles, CA http://users.cwnet.com/jgoodman/index.html *** this message was printed with recycled electrons ***Mike here: Rubberbanding is a good indicator of the need for retraining. Anytime you update the Autostar ROM or make any changes that would affect the gears or motors (like swapping them out), you need to retrain.
Subject: re: LXD-55 solar tracking Sent: Monday, May 19, 2003 08:11:34 From: Dick Seymour (rseymour@wolfenet.com To: galvan@dosgatos.com To answer your original question, you can change the tracking rate by: Setup > Telescope > Tracking Rate > Custom > and then enter a number. The "units" are tenths of a percent of sidereal. So Lunar tracking is -35 ( 3.5% slower than sidereal) Solar Tracking is about -1 (-0.1%) So, even if we can't find the -real- problem immediately, at least you can change the tracking to keep the sun in place. Does the scope go too fast? or too slow? The fact it tracks stars and planets OK is puzzling. More background on the Autostar's operation is at: http://www.weasner.com/etx/autostar/as_info.html You could also try locating bright stars or planets during the daytime to verify your alignment, but it sounds like you already have the setup and technique well worked out. good luck --dick
Subject: re: Solar Tracking (LXD55) Sent: Monday, May 19, 2003 08:31:26 From: Dick Seymour (rseymour@wolfenet.com) To: thx1326@swbell.net As the text says, the data are merely the exact moment of Spring (or the sun passing the Vernal Equinox). (my Almanac is not within reach, and i'm in a slight rush..) Even your Autostar can give you that number (under Events) The accuracy of the Asteroid method isn't too great, so the error from using an "old" year is not going to affect the results very much. (compare the results of the numbers given.. you'll see the result is functionally the same). have fun --dick
Subject: LXD-55 solar tracking Sent: Sunday, May 18, 2003 13:48:27 From: "A. Galvan" (galvan@dosgatos.com) My name is Tony Galvan. I live in Goleta and recently acquired a LXD-55 to replace an GM-11 and GT-1 I've had to sell due to a bad hip. Can't carry items over 30 pounds. I kept a C8 for solar work and find solar tracking very awkward with the LXD-55. I have a Nexstar5 and it does decent job of keeping the sun in the FOV but I need the extra focal lenght the C8 gives for solar viewing. I need the tracking for illustration purposes. Because of the hip problem I've given up astrophotography for the time being and gone back to the sketching activity. I tried the custom tracking rates and going up and down did not make any difference. I did a basic polar alignment and then slewed to the sun. The sun drifts out of view with a 25mm eyepiece in about 40 seconds. Mostly RA corrections. Are you aware of any firmware updates or patches which might incorporate the solar rate into the Autostar. While I miss my two monsters at least I can carry this unit. It holds a C8 and C102. Any suggestions are appreciated. tony Gato viejo, raton tierno Birdman to the Stars www.dosgatos.com www.dosgatos.com/africa www.dosgatos.com/astro www.dosgatos.com/birdsMike here: I suspect that any "fixed object" will also move out of the FOV if you are experiencing that much error in sidereal tracking. The Sun "moves" 360 degrees in one year. That is about 1 degree per day. Or 2.5 arc minutes per hour. Or 2.5 arc seconds per minute of time. That compares to the sidereal rate of 15 degrees per hour, or 15 arc minutes per minute. So with perfect sidereal tracking, in 1 minute of time the Sun would have moved only 2.5 arc seconds or about 0.1% of its diameter (0.5 degrees = 30 arc minutes = 1800 arc seconds). I doubt that you would detect that over the course of a normal observation.
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Do you suspect an RA motor problem? Is there a way to realign a target after say 10 minutes and then hold the Enter button down for the five seconds to reintialize? I've not done anything to the mount but I am going to disassemble to clean and relubricate with white lithium grease. When the locks are loose the RA and DEC movements do not move freely, unless it's grossly unbalanced. Not knowing anything about the Meade Auto series, does Meade not program solar rates on the other scopes? Would adding a planetary object allow it to track at a more acceptable rate? thanks for your help.Mike here: Well, I would suspect a polar alignment problem (not knowing how you are set up). If you are using the Autostar during the daytime you have to align the GEM to the proper polar axis and then (assuming you are even aligning the Autostar), accept the alignment stars as centered even though you can not see them (which is what I do during the daytime). There are two obvious questions: have you calibrated/trained the drives AND how is tracking at night?
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I did the auto align like you mentioned, accepting the two alignment stars that were chosen. It's also the same process I use with the Nexstar. My location is marked for the postion of each leg and the latitude angle is unchanged from a night session last week. I've used the mount once at night (just received it last week) with a C102 refractor and it did fine. Tracked the planets and the moon without any problems. GOTO was not dead center but within the FOV. I have not trained the motors.I am reading up in the training part and will do that during the week. As I understand it the mount should be able track the sun once polar aligned, correct? I'll train the motors and let you know how that works out. Thanks again. tMike here: Since the solar rate and the sidereal rate are so close, yes, you should be able to track once properly aligned. CALIBRATE and TRAIN DRIVES is a necessary step the first time a particular Autostar is used with a particular mount. After that, you only need to do it when you update the Autostar ROM or when it misbehaves.
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I will do calibration and training the week. I am also going to enter the coordinates for my observing site. Thanks for your help. t
Subject: Which Scope Sent: Friday, May 16, 2003 22:24:24 From: Csrr71@aol.com I am an amateur astronomer on the Gold Coast, Queensland, Australia. I have been interested in astronomy for 2 years now and I am thinking of purchasing a scope, either a LXD55 SN 10" a LXD55 SC 8" cor a LX90 8'. I am not to sure which way to go as the Equatorial Mount seesm to be complex whereas the idea of a LX90 fork mounts sounds easier. Also What benefit do I get by going for the 8" SC over the 10" SN. Does the SC make up for the 2" difference in apeture. Also the size of the tube on the SN concerns me., might be a bit hard to transport and store. And if I was to do Astro Photography would the fork amount be a disadvantage over the equatorial. While i'm writing I want to let you know I really find your site usefull and informative. Keep up the good work. Cheers Chris DouglasMike here: Yes, the LX90 is easier to set and use for visual and some photographic work. The LX90 has the same OTA as the LXD55 8"SC model so the difference is just the mount and drive mechanisms (better in the LX90). There have been reports that the 10"SN is a little too large for the LXD55 mount. If you want more details with larger images (planets, moon) then the longer focal length of the 8"SC versus the SN could be a factor. If you add the UHTC then you get more light to your eye than older 8" models.
Subject: Solar Tracking Sent: Wednesday, May 14, 2003 15:42:22 From: Thx1326 (thx1326@swbell.net) How come there are not any updated coordinates for solar tracking?The latest on the site is 2001.Is this a particularly hard thing to do?Or is there a site on the web where I can obtain and plug in the coordinates replacing those in the 2001 file? Thanks in advance for the help. Another opinion. Im thinking of doing a major upgrade. Ive been researching both the Meade LX200GPS / 12 and the Celestron 11GPS.Both have pros and cons.Drive and configuration in the Celestron looks a little better but the Meade has a electric micro focuser and one more inch of aperture.Celestron also seems to have the edge on motors and bearings. Any thoughts? Warp SN10-UHTC / AR6 LXD55Mike here: Which "site" do you mean for solar tracking? Meade (or its lawyers) doesn't like to provide sun viewing information. But since the sun is pretty easy to locate, with proper protection, you can just assume sidereal tracking. Over the viewing time you will probably look at the sun, tracking will be OK. As to Celestron vs Meade on the high-end, personally, I think Meade is more well established in professional telescopes. That's just an opinion based upon where I see Meade telescopes vs where I don't see similar Celestron telescopes. But I have only a limited sample size...
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Thanks for the feedback. I have always been a Meade supporter - they certainly have treated me right. However, the control layout, the motors, the arms, the bearings - all look ssubstantially better and more well thought out than on the Meade LX200 - not that it is not a nice scope - just details. Do you know anyone with a Celestron C11GPS that would give an opinion? If you do, have him email me. Thanks again!Mike here: OPT had a report on one on their website. I couldn't find it now but search their site; you might be able to find it.
Subject: re: LXD polar alignment problem/cleaning Sent: Saturday, May 10, 2003 20:46:01 From: Dick Seymour (rseymour@wolfenet.com) To: col@12kc.freeserve.co.uk You wrote: ====== I have tried to line upon Polaris and found that having set the declination of the scope to my home position of 51 degrees north, that Polaris is much higher in the sky. Does this mean I have to put in a much higher latitude on my scope (like 70 degrees?)? I thought that as a rule of thumb with the latitude position set, when the starred tripod leg is facing north and the scope is in line with that leg that Polaris was more or less in the finderscope. Could you help me please? ======= The DECLINATION of Polaris is 89 1/4 degrees So the barrel of the telescope should be so-close-it-hurts parallel to your RA axle. Parallel to the polar finder scope. You set the latitude adjustment of your tripod to 51, bring the barrel to Dec=90, which should be dead parallel to it (this is what the LXD55 Adjust procedure does) and evrybody should be aimed pretty close to Polaris. good luck --dickAnd more:
Sorry to bother you again. I am still unable toget Polarislined up. As far as I can see, the Home position should be when the star marked tripod lrg points north with the counterweight over it. With the latitude set correctly and the tube also pointing north, Polaris should be close to the field of view shouldn't it? I have just about managed to get the scope to angle 51 degrees north, but Polaris is still quite a bit higher. so there seems to be something wrong, and therefore the Autostar is not able to perform properly without lots of SYNCHing. I've tried to get the telescope to a higher latitude to line up with Polaris, but trying to get the T-handles to turn now is near-on impossible as the turns get stiffer and stiffer, and nowit is physically impossible to screw it any further as one T-bar handle is right up against the scope. In this case then the telescope cannot physically point any higher at the Polar Home Position. (What would I have done if I was at say 60 degrees north then?). Does this mean there might be something wrong with my mount? Also you said about the temperature equilibrium etc. meaning leaving the scope outside for 20-30 mins per inch of aperture. Does this mean leave it outside for 3 to 4 hours with an 8 inch LXD55 SC-8 for example?? I would be concerned about that re weather and people walking past my house. I have yet to see Jupiter any clearer really than with my ETX90 so I feel a bit disappointed at the moment. But I am waiting for my other eyepieces to come soon. I have an Orthoscopic(?) 9mm and it is not clear through there really either. I also have some specks of stuff on my glass. They won't come off with a fine puffer-brush, so what do you recommend to clean it? I have read various recipes......... I do hope I can get all these problems sorted, as I feel at the moment I have spent an awful lot of money for no extra satidfaction at the moment. I hope you don't mind helping me out Mike. Thank you. Regards Colin Scrivener, Herne Bay, EnglandMike here: Just to clarify, when you say "51 degrees latitude" do you mean you are raising the telescope GEM polar axis 51 degrees or 39 degrees above the northern horizon? If you remove the polar alignment scope cap and rotate the OTA so that the alignment scope is unobstructed, do you see Polaris through the alignment scope? Don't worry how close it is to the "crosshair"; I just want to know that it is in the field of view of the polar alignment scope. And yes, the T-handles do get "stiff" as you increase the "climb"; removing the counterweight and OTA until you get the latitude set correctly can help a lot. The longer you let the telescope cool down the better the views will be but don't sacrifice NOT using the telescope just waiting for it to reach thermal equilibrium. See the "Cleaning Optics" article on the Buyer/New User Tips page on my ETX Site.
Subject: LX55 SC-N8 vs ... Sent: Saturday, May 10, 2003 17:47:17 From: "Don Brabston" (brabston@ix.netcom.com) Your ETX and LXDD web sites are great! Ive been an amateur astronomer for 40-45 years, although I've not done any telescope observing for 30 years or so. (My son and I went out to the desert to observe the Leonid meteor shower a year and a half ago, which was beautiful. We also went on a tour upMauna Keawhere the tour company got out a couple of Clestron 8 scopes for an hour or so of observing. As my son said, I knew more astronomy than the tour guides did. My last telescope was a Criterion Dynascope 6 Newtonian reflector bought in about 1960.) At any rate, Im now considering buying a new telescope and am doing my normal system engineering tradeoff spreadsheet. I want to spend about $1000-$1200. I mainly want to do visual observing, but may want to add some simple photography later. I would like portability, so components (OTA, mount, etc.) in the neighborhood of 20-25 pounds individually should be about right. The Meade line of scopes looks like it has more selection than Celestron. Im considering an ETX-125EC (with the special deals of free Autostar, deluxe tripod, and the extra set of Plossl eyepieces), the LXD55 SC-8 and LXD55 SN-8 (both with Autostar GoTo controllers). Any thoughts on these scopes? What about the UHTC (Ultra-high Transmissions Coating) is it worth the price? The ETX-125EC with the free Autostar and tripod along with the extra Plossl eyepiece set is a really great deal. Hows the mount on the ETX? Is the ETX suitable for some photography? How is the LX55 mount? It seems that Ive seen some griping about the mounts on the Yahoo LX55 group. It seems to me that an f/8 scope (which is what my Dynascope had) should be about right. An f/10 is closer to f/8 than an f/4. The LXD55 SC-8 Schmidt-Cassegrain is an f/10, while the LXD55 SN-8 is an f/4. Would I notice the difference in visual observing? How about photography? I see on your website that you are working with OPT inOceanside. Ive talked a bit to Woodland Hills Camera & Telescope which is much nearer to me inManhattan Beach. What do you know about Woodland Hills? One last question (for now): in my youth, I didnt need glasses. Now I wear bifocals (sigh). Should I get a distance-only pair of glasses for observing or should I use the telescope focusing to observe without glasses? Once again, your web-site is great. I'll use it for a lot of tips whichever scope I choose. TIA for answering my questions. DonMike here: I like my LXD55-8"SC for the views; 8" f/10 makes a nice scope! But for ease of use and portability while still providing good views, the ETX line is the way to go. I have several models of the ETX telescopes; my ETX-90 gets the most use but for your purposes you probably want to look into the ETX-125EC. Yes, the current deals make the ETX a nice purchase; of course, you can get the $99 eyepiece set with the LXD55 as well. For some types of astrophotography, the ETX can do the job (as you can see on my ETX Site) but for slightly more serious photography, the LXD55 GEM mount will do better. If you want the largest view of planets, the 8"SC would be better than a SN; but for wide field use the SN would be best. Yes, the UHTC makes a definite difference, even on the ETX-90 (I've compared two ETX-90 telescopes, with and without UHTC). I recall reading lots of positive comments about Woodlands Hills but have no direct experience with them myself. As to glasses, you can probably focus the eyepiece to your eyes but if you want to avoid changing the focus for other people then you would want to use distance glasses since ideally the eye should be focused to infinity.
Subject: screws loose and corrector Sent: Saturday, May 10, 2003 10:55:49 From: ACG Tek LLC (acgtek@yahoo.com) I bought a 10 inch Schmidt Newtonian used for 965 dollars total. When it arrived, however, I was horrified to discover that two of the screws INSIDE the OTA that were holding the back of the mirror INSIDE of the OTA had fallen out. Through a painstaking effort, I managed to get them out. Now I am noticing that optics are being affected and wish to somehow get the screws back in. People have advised me to TAKE OFF the corrector plate and screw the screws in, which sounds like a very dangerous and accident-prone procedure. What do you think? Your opinion would be very much appreciated. Thank You ===== ACG Tek LLCMike here: Yes, that could be risky. Certainly you would need to recollimate (not a difficult task by itself). If you are careful you should be OK.
Subject: LXD55 8"SC Gear Problem Sent: Friday, May 9, 2003 09:06:14 From: GHVideos@aol.com I took my telescope outside the other night for the first time in over a month and noticed that whenever I changed direction in RA, the gears jumped. It's smooth enough as it moves, it just occurs when you change direction. I've never noticed this before. Any ideas? Many thanks. Hugh Palfrey EnglandAnd more:
I've just emailed you regarding a possible gear problem with RA. However, I've just removed the inspection panel and then used the autostar arrow keys to move it in RA. The gears appear to be working very smoothly. I have noticed, however, that when you lock the RA, there is a bit of play in the counterweight arm assembly. The counterweight bar and locking nut are tight enough, but you can see a bit of play (perhaps a 1/4 inch) in the GEM head itself. Could this be the cause?Mike here: Do you mean that the GEM head is loose on the tripod? I had a similar problem (but didn't know it at first). See the "Warnings" page.
And:
Thanks for your quick response. No, the GEM head is tight. No problem there. If you lock the RA and wiggle the end of the counterweight shaft there is slight movement in the RA assembly. When you use autostar to change directions, there is a noticable "jerk" in the tripod and GEM head caused by changing directions in RA. There definitely appears to be some internal problems with the mechanics. The GEM head is definitely tight, though. I experienced the same initial problems that you had with tightening it, but by lifting the head slightly prior to screwing the knob ensured a tight fit. Thanks again! Hugh EnglandMike here: Well, there should not be a jerk in movement. It sounds like something might be catching someplace. You might try slewing back and forth several times through a large range; perhaps that might loosen it up.
Subject: LXD polar alignment problem/cleaning Sent: Friday, May 9, 2003 15:13:25 From: "Colin Scrivener" (col@12kc.freeserve.co.uk) I wrote to you a few weeks ago, pondering over which telescope to buy. Well I plumped for the LXD55 SC-8 for the portability and the longer focal length. I have tried to line upon Polaris and found that having set the declination of the scope to my home position of 51 degrees north, that Polaris is much higher in the sky. Does this mean I have to put in a much higher latitude on my scope (like 70 degrees?)? I thought that as a rule of thumb with the latitude position set, when the starred tripod leg is facing north and the scope is in line with that leg that Polaris was more or less in the finderscope. Could you help me please? I have also noticed that looking at Jupiter for example, it seems to goclear sometimes then goes a bit fuzzy. The Moon is also very "shimmery". I am not sure if this is my eyes!! But I have also noticed twospecks on the objective glass as well as a sort of mark on my Barlow lens. I am not sure whatiscausing this "in and out of focussing", but have you any ideas and I would also like your best recommendation for cleaniing the glass. I think it will take me a while to get to grips with my new "Beast". Thank you very much for your time. Regards Colin Scrivener, UK, EnlgandMike here: There can several reasons why the latitude scale shows one thing and the sky another. The GEM head base might not be level, the scale might be off, or you might be seeing Polaris' difference of slightly less than one degree from the True North Pole position. I've started using the One Star Polar alignment and it seems to work fine if you follow the prompts. If you want more accuracy in polar alignment you would want to do the "drift method" of polar alignment BEFORE aligning using the Autostar. Are you allowing time for the telescope to reach thermal equilibrium with the outside air temperature? That can take 20-30 minutes per inch of aperture. The effect you describe sounds like either currents inside the tube or atmospheric currents. The latter can be caused by heating rising from rooftops, streets, or parking lots, or just from atmospheric turbulence. You might want to see the various articles on Telescope Performance on the "Observational Guides/References" page on my ETX Site.
Subject: re: Power to the scope... Sent: Monday, May 5, 2003 22:42:03 From: rseymour@wolfenet.com (Richard Seymour) To: jreed@esc18.net Your "500 amp" battery should work quite happily. The "300 amp" battery would also work happily, just for half the time. Those numbers are "cold cranking amps" (CCA)... and are a reasonable number for selling the battery to the car-starting market. But they have little information for our (relatively) low-current usage. For us, "ampere hours" (AH) are the more useful number. I've done web-trawls on the subject, and the answers range from: "there's no correlation between AH and CCA" to some simple formula (which i forget.. let's say it's CCA/x=AH, and i forget the X) I'd guess that the 500 CCA corresponds to a 17 AH battery. And a 17 AH battery can operate an LXD55 for about 10 hours. Mike has assembled a large spreadsheet of these things, http://www.weasner.com/etx/buyer-newuser-tips/powersupplytable.html look for any with 500 or 300 in their model numbers for rough equivalences. have fun --dick (who uses a 17AH on his LX200gps)And:
Joe Reed wrote: > > Thank you!!!!!!! My mind has been eased. I surely didn't want to fry my > new computer. I really appreciate all the help. Whoa! I forgot to mention that it's not a great idea to run other devices from your telescope's battery ...without knowing how they operate. The best method is to have a separate battery for Kendricks-style dew-heaters (they have an electrically "noisy" controller), although simple always-on homemade "resistive" heaters are safe. Laptops are another potential source of problems... *some* 12v-to-laptop are wired such that if you connect the laptop to the telescope you pass full battery voltage through the "common ground". Safe ones carry the battery's negative terminal through the 12-to-laptop up-converter ... unsafe ones (and i'm told RadioShack sells some of these) pass the +12v line through the converter as the common wire. Folks on the LX200gps group have reported having their rs232 serial line (the 505) get very very hot (melted insulation) in such a battery-telescope-505-laptop-RadShack->back-to-same-battery hookup. Two separate batteries would be safe. have (safe) fun --dickAnd more:
Mike Weasner wrote: > > Thanks for the clarification Dick. I have said I'm not an electrical > engineer! I am. > I always get confused by all these numbers!!! I find the cold cranking amps (CCA) an extremely misleading spec. (although, back in my car days, it was my physicist friends who were adamant to buy batteries based upon the "lowest internal cell resistance" which can be directly converted to CCA. As your next electrical engineering lesson: the AMP rating of a battery is a capacity rating: similar to "how many gallons does the the water tank hold". The CCA is similar to: "how big across, and how long, is the hose from the tank to me". Voltage is "how tall is the tank, or how powerful is the pump forcing water down that pipe" (i.e. pressure). Voltage is usually the thing which causes damage to circuitry. Amperage doesn't hurt (unless something else goes wrong). A fuse in the wire prevents "amperage"-related damage. have (wet or dry) fun --dick
Subject: Mounting non-Meade scopes on the LXD-55
Sent: Monday, May 5, 2003 09:35:19
From: "MORRIS, MARK" (MMORRIS@mii-rmcc.com)
I have not chimed in for a while but I still check every update, on both
sites. And both are as usefull as ever. Your step-by-step on removing
the RA gear box and tightening the gear set screws will be invaluable
for many of us. Thank You!!
The adapter plate needed to mount ota's to the LXD-55 is the same as for
the Vixen, Celestron, and Orion mounts. I have a TV-76 mounted on my
LXD-55 Mount using a Great Polaris adapter plate. So, a c-102 should
mount with a CG-5 adapter plate.
Mark A. Morris
Subject: What is the best value at 8'' Sent: Sunday, May 4, 2003 20:01:36 From: Anonymous This is a wonderful site and we all thank u for thatJ I really have to make a tough decision on which telescope LXD 55 8SC UHTC ($1350) or LX90 UHTC ($1650) or LX200 GPS UHTC($2150) is the best value for money and really need some expert advice. I would have already bought the LXD55 SC if they weren t all these problem reports. Is there any good article that compare all of the above scopes. It s even getting more confusing with all these offers. Which one is the best for astrophotography? Thanks in advanceMike here: The simple answer is "look at the price". The 8"SC OTA is the same on all three models. The best for astrophotography would be the LX200. The best all-around for less cost would be the LX90. At the lowest cost end is the LXD55.
Subject: LXD55 questions Sent: Thursday, May 1, 2003 12:27:57 From: "John K. Goodman" (jgoodman@rhythm.com) I wrote to you before regarding purchasing the LXD 55 SC8". I have purchased it since then, but have been having some basic problems I dearly hope you can help me with. (Meade has not been much help at all.) Please bear with me here, as Im trying to understand whether its user error(probable), or a bad mount(I hope not). Im a generally very technical person, but I feel like an idiot with this. However I also feel like Im getting close to understanding it. _______________________ Before doing all this I have trained the drives and calibrated them. 1. I set up the tripod. Its leveled perfectly. Facing north perfectly. 2. I attach the mount and I set up the Polar Home position as specified on page 17 of the manual (I have already tediously aligned the polar scope eyepiece using the allen screws) Im in LA so my latitude is set to 34 degrees. (give or take a bit to get polaris perfectly centered in the polar scope) 3. In helping to set up PHP, I used the setup at OPT's pages here: http://www.optcorp.com/pdf/TipsTricks1.pdf I balance everything and attached arrow decals as specified. Easy to get back to PHP now. 4. I tweak the dovetail so the scope and 8x50 finder are also aligned with the polar scope. Everything has polaris centered now. 5. I turn the DEC setting circle to 90degrees. This is done according to the instructions on page 50 of the manual Appendix B "Axis Alignment Procedure" a. what does this accomplish exactly? it doesnt tell the autostar anything right? (in fact when the scope is set to PHP the Autostars DEC readout is *NOT* 90 degrees, but more like 0 degrees)... b. what does setting the DEC setting circle to 90deg do? c. what should the RA setting circle be set to? Im using this for now, to set the RA setting circle. www.geocities.com/jascarden/addendum/polar_alignment1.htm d. What is the purpose of setting circles when you have autostar? this is a fundamental thing Im not understanding and is probably key to my problems, but anyway.... Now, the crux of the problem... 6. If I do an easy align, it says "make sure youre Polar aligned" and hit Enter. Well, I am already, so I hit enter, and it says (e.g.) "Slewing to Arcturus". But it invariably winds up nowhere near Arcturus, usually 20-30 degrees further east. So I use the AS arrows and line it up and sync. Then I tell it to goto back to Polaris and it again goes way off, nowhere near Polaris. I again use the AS arrows, line Polaris up and sync it. Then I tell it to go back to Arcturus. Its way off again. You get the idea by now. 7. If I do one or two-star align, starting from PHP, the scope first slews way over to the left in RA, does a little DEC adjustment, and then asks me to re-center Polaris using the alt/az knobs on the lower mount. (Is this right? Why does it do this if ive already aligned polaris in Polar Home? why is it slewing way over and then asking me to realign? is it a cord wrap thing?) Anyway, so i do, and then it tries to find Arcturus. But it invariably winds up nowhere near Arcturus, usually 20-30 degrees further east. So I use the AS arrows and blah blah blah, same as above. Do you have cord wrap turned on or off? would this affect #7 in anyway? Also, as a test, when i set the setting circles to match the Autostar RA/DEC settings, and then slew in both axis, the RA circle will still always match the Autostar RA setting, BUT the DEC circle always goes out of sync with the Autostar DEC setting. Is this normal? is it the same on your mount? Does it really matter? or is the DEC encoder hosed? is there another way to tell? Do I need to do the LXD55 Adjust menu item as stated in page 53 of the manual? Have you done this? did it help anything? I guess thats it for now, I know this is long and tedious and probably very basic, but Mike If you have time to reply Id sure appreciate it. I generally love this scope and mount and just want to be able to operate it correctly. Thanks very much. -- _____________________________________________ John K. Goodman - Character Animator/TD Rhythm & Hues Studios - Los Angeles, CA http://users.cwnet.com/jgoodman/index.html *** Do geese see God? ***Mike here: Generally, ignore the setting circles when using the Autostar. Here's what I used to do: set up in the Home position (Polaris in the Finderscope), select Easy 2 star, center each star when prompted (wait for the beep!). This usually gets good GOTOs. However, I recently tried using the 1 star alignment. Follow the prompts to center Polaris and then center the alignment star when prompted. This seems (in my brief usage) to give better GOTOs. I live just south of LA so I use the same latitude (I'm using Torrance actually). Cord wrap is for the ETX models and likely has no affect on the LXD55 mount; it is just to avoid an internal cable from wrapping up as the ETX rotates. Initial alignment star errors of 15 or 30 degrees sounds like a TIME error; check Daylight Savings in the Autostar. As to the mechnical tweaks you have done, I haven't done them (no apparent need to yet). Let me know if the procedures I've described help.
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