Cgem declination backlash. reverted back t0 PHD 1.

Cgem declination backlash Once they were tightened up the "play" was gone. Thus, the wobble Oct 22, 2019 · Declination Backlash in my Eq6R Pro mount - posted in Equipment (No astrophotography): While Im still getting fairly good results in PHD2, every time I run the guiding assistant it tells me there is a backlash reading between 11 and up to 20 seconds. Nov 16, 2012 · Further, some of the lower-end mounts have severe declination guiding problems, to the point that one enterprising person has created the "motor3" where he actually moves the entire mount to do declination guiding corrections. [PDF] Test for Right Ascension (RA) backlash and correction. Ive got it set up in ASCOM with the meade LX200GPS/R driver, and Ive deleted and reloaded both and it and the PHD2 program multiple times in the last month, so theyre both up to date. PHD2s guiding assistant measures about 600-750ms of backlash in declination Mar 31, 2014 · Periodic Drift on the Declination Axis - posted in Mounts: I have a relatively new Celestron AVX mount that actually guides and tracks fairly well (RA RMS values of about 0. The drive system, consisting of low cog DC Servo motors with integrated optical encoders, steel worm gears supported by precision sealed bearings, and brass worm wheels, ensures May 26, 2014 · My question concerns the balancing of an 11" Schmidt cassegrain on the declination axis. If you believe that the declination axis (DEC) of your HDX110 EQ-G mount has unwanted backlash, or on the contrary that the DEC worm and ring gear are binding due to being too tightly meshed, follow this procedure for adjusting the gear mesh. The moon moved 1/2-way Feb 19, 2012 · Declination guiding oscillations and drift - posted in Mounts: Ive been having some challenges with declination guiding on my AP600E. The fix appears to be relatively simple. Declination Backlash. When you are autoguiding, the guider movement is always less than the tracking rate, so the motor never reverses. Nov 14, 2022 · The CGEM, once the gearboxes are properly rebuilt track as well as your AZEQ6GT. Thats a big difference for someone who has on and off back The CGEM DX mount is equipped with a mounting plate that r. I basically have to choose between less backlash and less sound Jul 10, 2016 · Tuning CGEM for backlash or gear mesh - posted in Mounts: So I have been trying to fix my Cgem after a fall on grass a couple of months ago. Issue: The declination goto continues to move, not appearing to know where it is. The dec shaft is not true so I have varying backlash depending on the declination of the object. PHD came with the camera but Ive been having some problems getting it to track properly. Celestron CGEM 925 HD Computerized Telescope CGEM Series Manual - Page 26. Nov 8, 2008 · Celestron CG-4: slight rocking in declination - posted in Mounts: Is it normal for the head of my CG-4 to move slightly forward and back around its pivot (in declination) when a slight torque is applied to the end of the mounted optical tube? The declination axis is properly locked in place, but it does sometimes behave in this manner such as when I unintentionally apply too much force to the Feb 2, 2019 · CGEM gear reduction motor backlash - posted in Mounts: Just bought a used CGEM mount and found an issue with the gear reduction assembly in the RA motor. It took it forever to take up the backlash (the calibration detection in PHD didn't seem to handle that) so that by the time it recovered, it would typically overshoot the other Jun 27, 2019 · I reset everything, adjust the declination locking screw out about half a turn and the next guiding assistant gave me backlash of about 1500 and was able to recommend settings to correct it out. BTW, the RA and DEC gearboxes on my CGEM are interchangeable and, at one point, I did interchange them to see what happens. For the record, I am not using a friendly setup for this endeavor and I am considering cooling my jets and just going planetary until another mount is in the budget. Aug 24, 2024 · CGEM (version 1) Backlash - posted in Mounts: This has to be already covered but I cant find it. The computer could then drive both the DEC and RA motors to compensate for the misalignment Feb 17, 2012 · well. Stars through the guidescope w/ guide camera are perfect, and PHD2 can easily find and lock onto a star, and I am positive the camera settings/focal length in Apr 16, 2007 · Backlash is "play" in the gears which you can feel by trying to rotate the axis with your hands while it is locked. The amount of compensation neede d depends on May 6, 2013 · Dec Cogging on CG-5? - posted in Mounts: I have a CG-5 and auto-guiding in Declination has been a real exercise in frustration. According to Celestron, the mount, tripod and counter weight combined is about 91 lbs not including the OTA which will be an 8 Edge HD. If you slightly imbalance your mount (East heavy) the motor is always pushing the mount to the west, gravity is trying to keep it in the east. I suppose I should have expected that considering how much of Astronomy uses estimates. May 28, 2021 · My mount is belt modded, that reduces part of the backlash so take it in consideration. The first backlash is the gearbox backlash which extends from the motor to the worm gear. I currently have a CGEM that Ive performed a DIY hypertune on and with my Edge HD 8 w/ . Apr 11, 2012 · my point is that the CGEM with a long-FL load like the 9. Aug 31, 2021 · Page 2 of 2 - CGEM DEC motor gearbox backlash? - posted in Experienced Deep Sky Imaging: Scott Badger, Not sure if you are still here or not as it is over 2yrs from the lasts posts to this topic. My experiences nearly mirrors yours. plus mine has un-removable backlash on the DEC axis. Wondering if experts can advise if this looks more like Backlash, or Stiction. But the corona virus gives me a good opportunity to start using it again. due to imbalance, wind, a bump) and can't correct in time because of the huge backlash, this causes egg stars. As I watched, the dec line plunged completely off the screen and didnt come back up for about 5 of the horizontal graph graduations. When slewing under power the Aug 17, 2017 · Page 1 of 2 - east heavy balance. 5 arc seconds). 11097 CGEM 800 11098 CGEM 925 11099 CGEM 1100 203mm (8") SchmidtCassegrain 2032mm F/10 6x30 CGEM Computerized Equatorial Optical Coatings - Standard Secondary Mirror Obstruction by Area by Diameter Optical tube length Telescope Weight 480x 29x 14 . I noticed this, as well, and finally decided to open the gear box and see what I could learn. You would use a CGEM II if your telescope is too heavy for an AVX to carry, bearing in mind the 50% rule. This is especially true on new mounts direct from the factory. After experiencing nasty sticking in the RA Axis and (to a greater degree) the Declination Axis, I sent the mount off to be HyperTuned by Deep Space Products. Easy Problems To get warmed up, we can start by looking at some easy problems to diagnose. If I grab the counterweight shaft, there is a small about of play in the RA axis. I just took delivery of one and first impressions are positive. (azimuth axis of the se), the excessive backlash in the elevation gears gave it fits in guiding declination. But the alignment must be dead on because it simply will not autoguide in declination. I feel as though I am May 7, 2019 · Page 1 of 2 - Do these PHD2 graphs ring any bells? - posted in DSLR, Mirrorless & General-Purpose Digital Camera DSO Imaging: What is causing my AVX to be plagued by these sudden southward excursions, one every few minutes at irregular intervals? They show up as streaked or doubled star images. This will induce a small amount of declination drift. The declination o Buy Celestron CGEM II GoTo German Equatorial Mount with Tripod featuring Motorized Computer-Controlled EQ Mount, Low-Cog Dual-Axis DC Servo Motors, NexStar+ GoTo Hand Controller, 40,000+ Database, User-Defined Objects, Multiple Slew and Tracking Rates, Multiple Alignment Procedures, Backlash Compensation, Permanent PEC, Dual Vixen/CG-5 & Losmandy/CGE Saddle, 2" Steel Adjustable Tripod with Sep 26, 2016 · CGEM DX Backlash Question - posted in Mounts: Hello, The other evening while out observing, I had slewed to Mars and got it centered in the eyepiece. The ergonomically-designed CGEM II has a fresh, attractive, bold appearance – and a 40 pound payload capacity. I stopped the 1 – Strip Down and Cleaning of the Declination Axis; 2 – Lubrication and Reassembly of the Declination Axis; 3 – Strip Down and Cleaning of the Right Ascension Axis; 4 – Lubrication and Reassembly of the Right Ascension Axis; 5 – Adjusting Worm Gear Engagement – Motor Gears; 6 – Adjusting the Altitude Thrust Bearings The Advanced VX has basically no declination bearing and suffers from horrible backlash, periodic error, and guiding problems which cannot be fully remedied even with extensive DIY modifications. 60 - 0. 68 arc seconds . Nov 2, 2016 · CGEM with declination play. a. Nov 19, 2009 · CGEM Right Ascension Play - posted in Mounts: I just noticed a slight amount of play in the right ascension axis of my CGEM mount. I noticed this when looking at the moon last night. I think I got the gear mesh adjustment figured out and my DEC is pretty good. I had walked away and when I came back Mars had drifted to the left side of the eyepiece and when I attempted to recenter it the mount would not respond in the right direction. . Forgive me for this Normally, the mount just made the familiar rrreeeeeeeeeeeeee noise when slewing. both the right ascension and declination axes. Turn declination backlash correction on and set the maximum to 5000 or more. 14. 16 ArcSec RMS, as customer tested over 5 nights with an ES127. Sometimes the mount will go off in one direction (e. It usually only takes one Dec 26, 2020 · CGEM Declination Failure - posted in Mounts: Got a problem. View and Download Celestron CGEM 1100 instruction manual online. My first impression: Wow, I can actually balance the Decl Axis, thats pretty cool! Before servicing, the Decl Axis was sticking so . please look at the Declination axis. 7x focal reducer and celestron OAG with asi290mm Im able to pull off 0. The CGEM anti-backlash features allows the user to compensate for backlash by inputting a value which quickly rewinds the motors just enough to eliminate the play between gears. Set the RATE value to the one you use move often when manually slewing the scope - generally 4, 5 or 6. Im wanting to better tune my CGEMs backlash compensation. In this example, the guiding was about as good as the seeing conditions would allow. Then eventually, the declination axis gets far enough off, and I get a big correction back. Feb 23, 2024 · Page 1 of 2 - Declination issues. In short, it will be so difficult you will very likely quit. 17 - First version supporting the CGEM DX mount. Are you using the relays or ASCOM? I've found on many of the mounts I have owned that declination guiding through ASCOM results in 'backlash'. I ended up adjusting my polar alignment to ensure I was off in declination (using the declination adjustment on the mount) and then guiding in one direction using PhD. I can jiggle it back and forward a little. If it wiggles back and forth - that's backlash. Watching a lot of videos and I still come up stumped. Nov 8, 2019 · On a Celestron CGEM is it possible to move the telescope mount on top of the declination axis so that home position and the hole through the shaft for polar alignment are in line. I recently finished a hypertune of my CGEM (which went reasonably well and taught me a lot about the mount) and believe I have increased the backlash! The RA axis wiggles (whether fully loaded or not) about 3/32". If I hadn’t come across a second-hand CGEM for a good price, I was actually looking at the Orion Atlas Pro AZ/EQ-G, which also happen to be on sale for $200 off right now. My backlash is about 2. In fact, when doing drift measurements the DEC Celestron CGEM II – The CGEM II is little more than a scaled-up Advanced VX with a bigger mount head but otherwise, the same features and problems with its design. I loosened the four 5mm allen bolts and then for DEC and RA, I loosened one of the 2mm screws by 1/2 turn and then I tried to tightened the opposite 2mm screw. - posted in Mounts: Hi there! I seen many comments about the CGEM mount, and looking in to the different threads I found that making the Hypertune to my Mount will help to solve some issues while I improve the performace. Many time I have read to unbalance the mount so it is east heavy. It was reported many times. This is an AVX that has large declination backlash. I had the same issue with my Orion SkyView Pro mount. Jan 17, 2021 · As it turns out, the only “precision measurement” required during the field to clean much of the Declination backlash was a slight turn of a screw driver to force the Declination motor gear a little closer to its neighbor. As I was focusing, the scope would the slight distance with the pressure from my fingers. Figure 1. Jan 17, 2011 · Page 1 of 2 - CGE Pro -- Current Issue List - posted in Mounts: Hi all,If any of you CGE Pro owners could add to this thread with issues that youve had (or have) with this mount along with any success youve had in repairing the issue (alone or *cough* with Celestrons help), Id appreciate it. Jan 13, 2022 · AM5 has backlash on DEC. However, excess backlash can cause a delay in scope movement when using the hand control’s direction arrows. It wasnt that noticeable during gotos or slewing but when balancing, the RA would stick. I am definitely not getting good guiding. I use a Celestron CGEM for my mount. I understood what that means I just do not know how to do it properly. Again, declination backlash and stiction is not so obvious at small image scales, say anything above 2" / pixel. Oct 8, 2014 · About one month ago I tried adjusting the RA and DEC gear mesh on my CGEM. Ive been trying to work out this issue for the last couple of days and its driving me crazy. Feb 28, 2014 · For declination, one reasonable strategy is to have the scope intentionally off polar alignment by a small amount. The CGEM II is an excellent performer for visual astronomy as well as planetary imaging, which has similarly lax tolerances for tracking quality. I do have noticeable play in declination, which I think will be a matter of adjustment in some of the internal components. This avoids backlash, which is the biggest problem guiding in declination. View all Celestron CGEM - 925 Computerized Telescope manuals Jun 20, 2012 · My CG-5 has annoying declination backlash which turns auto guiding into operator intervention guiding . 8 rms then there is very little gain to be chased down reducing the backlash and I would spend the time on the skies and ignore the devil on your shoulder. However, Im having a problem on declination that seems to match the approximately ten minute worm and spur gear period that is common on a mounts polar/RA axis. Specifically, I tested it as follows (in daylight): Turn on, confirm location at the fixed RA and DEC indicator arrows; confirm time and location (etc). 57 arc seconds 843x unaided eye Dec 29, 2010 · Page 1 of 2 - PHD-CGEM Guiding Problem - posted in Beginning Deep Sky Imaging: What would cause the dec guiding to go whacky. I have a CGEM for +11 years with 2yrs under a TeleGizmo365 cover and then 9yrs in my outhouse Jun 4, 2018 · Newest PHD2 has much better DEC backlash comp. I do DSLR astrophotograhy with a main scope being celestron 8” SCT. Sep 12, 2011 · What's Wrong with the Celestron CGEM Mount? Greg Marshall, 9/12/11. 1) does the G-11 need to be East-heavy? 2) how sensitive is it to declination balance? 3) are there problems guiding in declination? (excessive backlash, stiction) 4) how sensitive is it to balance? For context, I started seriously trying to image with a CGEM Dec 15, 2024 · The Orion Sirius is what we call an entry-level, Computerized German Equatorial Mount, or CGEM for short. When the mount does a goto to a star in the east, it appears to finish its goto by moving ‘higher’ in the sky I. I mounted my Meade LX90 8 on a used Celestron CGEM version 1 mount. The gears must be checked across the full range of motion. But my quick calculation over a bearing distance of 100mm suggests less than 1/10 that amount. My mount is more than 10 years old and admittedly I have not been using it because of busy schedules. You could try enabling that. Jun 9, 2016 · CGEM- gear adjustment or backlash? - posted in Mounts: Was using the CGEM last night and alignment was a real pia Problem seems to be when I am placing the star in the reticle center using fine adjustment the keypress on direction key can take 5-15s before the mount actually moves. I checked the RA locking brake and it is tight. Probably, in his view, proper threading with a larger-diameter bore is good enough (there will also be more Jul 31, 2020 · The CGEM can have enormous backlash in declination. Jul 4, 2013 · Used the cgem hc to move star North when clear dec backlash came up, star did move nicely 3 pix north and N calibrate started and 45 steps later star did not move. 5 minute test Feb 13, 2020 · The CGEM II has larger worm wheels, can carry more weight, has a bearing in declination, but otherwise is just about the same precision as the AVX. However, it also seems to affect the amplitude or aggressiveness of the backlash Oct 12, 2021 · Never look at the graph and concentrate of the roundness of the stars. That software stand a chance, mass produced mounts need to be as mechanically perfect as you can get. Point the scope towards the southeast, up at about 45 degrees from the horizon. Spacers were low-grade, hard plastic, and spacing was poorly implemented; Motor spur gears were not meshed properly Mar 10, 2013 · The CGEM mount will always have a little bit of backlash - it's just not manufactured better. During tracking, the declination axis is completely stopped (there are some high end mounts that can use a custom tracking model that does declination correction, which can run the declination motor *very* slowly, but that's not happening here). It seems that the HyperTune has left the movements in RA and declination so smooth, that the saddle knobs on the declination axis are now heavy enough to cause the 6 AT6RC telescope to fall/rotate in their direction when clutch is not 4 0. Not exclusive to longer exposures, but the probability increases the longer you go. On the back end I use a 2" visual back with a televue shorty diagonal and televue eyepieces, a tetrad and a 9x50 orion viewfinder (straight-thru). You have the ability to set max backlash comp value, and it detects oscillation caused by excessive DEC correction much much better than before. The CGX is a much heavier payload mount than the CGEM II and is also far more reliable and autonomous, qualities I’ve come to appreciate both as an astrophotographer and when I’m observing visually. I didn't notice any significant change in DEC backlash but the RA PEC curve had to be retrained. During this interval, the declination gears aren't fully engaged and the axis doesn't Dec 14, 2023 · The motors come out and go back in pretty easy, access is under the connector/power cover. At this moment it sells for $1179 (May, 2023) and is regularly “on-sale”, making it one of the few entry-level astrophotography mounts around the $1000 dollar range you can use with a decent telescope and camera. The Declination axis is tight. As a result, Ive been doing a lot of research. Peter . You'll see in the article that you want somewhere between 8 to 20 steps for RA and declination. g. So lets say I use a solar filter could I adjust backlash effectively with the sun? I could use a reticle and place the edge of the sun at center and then Aug 9, 2017 · CGX DEC backlash sanity check - posted in Mounts: I cant seem to get decent guiding no matter what I do and getting a round star isnt possible unless I do really quick exposures. I still had a residual 1. 5 guiding speed (maybe more, can't recall exactly). After fixing things like belt mesh and worm gear mesh, I am now focused on the gear mesh inside the RA/dec motor housing. Simple trigonometry suggests that a tilt of 5 microns over a distance of 100mm results in a 10 arc second change. The amount of compensation needed depends on the slewing rate selected; the slower the slewing rate the longer it will take for the star to appear to move in the eyepiece. Im 99% sure my mount is about as good as it can be mechanically as Ive spent considerable time hypertuning it. The second backlash is between the worm gear and the king gear. then the star jumps in the reverse direction, and the commands go the Jul 8, 2010 · Page 1 of 2 - CGEM Problem - Worm Adjustment - posted in Mounts: Heres the setupI took my CGEM out 2 nights ago, Tuesday night, and I experienced trouble. In the 7 seconds it would take to wind up the backlash (running at guide rate) the guiding parameters may have changed. 00286 degrees = 10 arc seconds. Once ready, select “Start Training” and wait for the number of cycles chosen to be recorded. Was it worth it? - posted in Mounts: Hi All, Im currently staring at this sale everyday for the Skywatcher EQ6R pro, its very tempting to buy. That’s the standard configuration for a lot of mounts. The declination axis is a different beast. Azm Backlash corresponds to the left/right buttons, while Alt Backlash corresponds to the up/down button. It picks Aug 27, 2012 · Page 2 of 2 - CGEM Declination axis shift - posted in Mounts: Stan, I dont see the need for insinuating that helicoils would not be propitious for Eds business. Confirm for a one-star alignment. I have tried some manual guiding as PHD2 suggests. It is also worth noting that for me I find low DEC aggression works best with backlash comp to minimize over correction. I believe that, when you’re just getting into the hobby, it’s vitally important to realize that the mount is more important than the telescope you plan to Aug 29, 2014 · Page 2 of 3 - cgem tracking vs avx tracking - posted in Mounts: Im not certain where you get that +/-50 microns. I have a Celestron CGEM mount Dec 17, 2024 · The Celestron CGX is Celestron’s newest heavy-payload computerized equatorial mount and is, in a way, the successor to the Celestron CGEM II and CGE mounts. There is absolutely no play in the declination worm and as little backlash in the gears as possible without binding them. This causes big Jun 15, 2022 · But by far the best way to solve backlash issues is to dismantle DEC, clean, re-grease and adjust. Some mounts have backlash compensation where they run at a (much higher) speed when the axis reverses. The counterweight shaft is also screwed in tight. If you are new to astronomy, you may wish to start off by using Aug 27, 2012 · Page 1 of 2 - CGEM Declination axis shift - posted in Mounts: Last night I noticed a slight shift or rocking in my dec axis. Also, set the declination guide speed (a setting made with the mount's hand box) to 90% instead of 50%. 2 sec with 0. 005/100) = 0. Jul 8, 2013 · Scoring found on the Declination ring gear; Backlash screws in DEC were cross-threaded and had to be reworked. Backlash or Stiction ? PHD2 - posted in Beginning Deep Sky Imaging: Hello Imagers. Backlash can occur when the direction of motion on the axis is reversed. and it still has an eye-popping amount of declination backlash. Feb 3, 2020 · Celestron Advanced VX Review Video Main advantages of the Celestron AVX Price. I know Im a n00b but now Im starting to wonder if its lack of experience or something else. This mount is pretty well designed in that it is belt driven, so there’s only one place where backlash could occur: on the worm itself. It seems like it is inconsistent. Sometimes it responds, sometimes not. That would make guiding in declination a big problem. arctan (0. Heres a sample PHD graph: I did some measurements of my declination backlash and its about 20 arc-seconds Ive been advised to mis-align my polar axis a bit (right now I can do 4 minutes unguided @ 720mm) so that declination corrections will only be in one direction. 6. However, when fully assembled Aug 29, 2014 · The CGEM can be guided in Dec as long as it doesn't have to reverse in direction and it doesn't have the periodic variation in Dec tracking. I would have thought these were stiction except Declination Backlash Compensation Most commonly-used mounts have some backlash in declination. I often try for as long sub-length as I can Oct 17, 2010 · CGEM Backlash and Special Rate 9 interaction - posted in Mounts: Today while doing testing to isolate an ST4 South guide signal failure, I seem to have found another benefit for changing the Special Rate 9 slew rate. CGEM II telescope mount The CGEM II German equatorial mount has been designed with the highest quality materials to ensure stability and durability All this adds up to a telescope that gives you a lifetime of enjoyment with a minimal amount of maintenance Furthermore, the CGEM II mount is versatile — it will grow Buy Celestron 11" SCT Telescope with CGEM II Equatorial Mount featuring 11" Catadioptric Telescope, f/10 Focal Ratio, 2800mm Focal Length, StarBright XLT Optical Coating System, Database of 40,000+ Objects, Multiple Alignment Systems. You can also find topics like "Huge backlash on AM5" on the Zwo forum and other sources on the web. Our StellarDrive 6R ULTRA, based on the EQ6-R will run 0. Oct 10, 2017 · Beginner guiding woes (CGEM + PHD2 + SharpCap) - posted in Beginning Deep Sky Imaging: Hola! Reaching out to the CN populace for some help, thanks for any advice! So Ive begun trying to PHD2 guide with my new qhy5l-ii-m and attempting to polar align through SharpCap. Jun 9, 2022 · You can get around backlash in PHD2 quite easily. I can mostly deal with the backlash in PHD2, especially if the seeing is good and no wind, but it prevents me from ever getting a calibration without one of the warnings (not the same Aug 3, 2021 · For most mounts, 6-10 cycles are ideal, but for the CGEM, CGEM II, and CGEM DX, we recommend using a multiple of 3 runs (3, 6, 9) to give the best results due to their non-integer gearing. On the front end I have a soft dew shield. For my seteup I use a 400mm focal length refractor guide scope attached to the mount with a QHY5 guidecam. Sep 29, 2012 · mount option - posted in Mounts: I have a CG5AT which has worked well. I have a question for the mentors around here. The DEC is toodling along on its merry way, and then there is suddenly a huge ~ 1/2 arc-minute lurch, after which guide pulses have no effect, followed by a double sized lurch in the opposite direction, again with guide pulses having no Dec 7, 2017 · Celestron CG-5 backlash limits - posted in Mounts: I have quite an old celestron cg-5 mount and in recent times I’ve noticed declination backlash becoming worse and worse. There is no need to over-analyze the difference between these two mounts. 6 arc-sec. For equatorial mounts with built-in motors on both the Dec and RA axes (both go-to mounts and non-go-to but motorized mounts) there are some additional habits you can form, when using the electronic control pad, to reduce the impact of backlash. I do want to know if this is Feb 17, 2012 · well. It became progressively worse and two weeks ago, a rubbing The CGEM II, with its 40 lbs load capacity, is the latest update to the venerable CGEM mount and provides a sturdy and rigid platform for the fully-loaded RASA 8. alanCinG thE ount in accepts the Celestron CGE style (3”) dovetail bar . The "wha-wha" sound is not bad for the mount. Doing this over and over it seems even after placing calibration stars that the final alignment would be Sep 16, 2013 · CGEM DX & PHD declination flatline - posted in Mounts: Hi all,I just setup a new CGEM DX with an Orion Awesome autoguider for astro tracking. I can see this in my guiding graph with the Yaxis (declination) in Maxim, as the graph shows very little variation around the centroid position. Jan 20, 2011 · Page 1 of 2 - CGE Pro Declination Play Fixed - posted in Mounts: A few people have encountered an issue with their CGE Pro where there was some play in the declination axis. PHD will send guiding pulses but nothing seems to happen. Series Mount! The CGEM DX series continues in Celestron’s proud tradition combining large aperture optics with the sophistication and ease of use of our computerized GoTo mount . The mount gave unacceptable results at 750 mm focal length . 25, which is much heavier than the 80 mm APO. A CGEM is a must-have bit of gear and the foundation of any astrophotography rig. 25, recovers slowly from vibrations. 25 on a CGEM mount. When I open the graph function in PHD the declination axis is flat-lined and the tracking is inaccurate. - posted in Mounts: OK, very rookie question. The telescope may not immediately start moving in the reverse direction, even though the motor is turning. CGEM II telescope mount The CGEM II German equatorial mount has been designed with the highest quality materials to ensure stability and durability All this adds up to a telescope that gives you a lifetime of enjoyment with a minimal amount of maintenance Furthermore, the CGEM II mount is versatile — it will grow Mar 25, 2020 · I finally decided to just test the backlash on the declination axis by slightly pushing on the telescope while it was mounted. Had to do an impromptu tuning procedure to get the RA axis to rotate smoothly so I could balance it well. All telescope motor drives have some backlash because, if gears are too tight, they can cause motor binding, premature gear wear, and inaccurate tracking. The CGEM is considerably more massive. Howe Jul 29, 2017 · CGEM Worm adjustment bolt locations? - posted in Mounts: I have some slop in both RA and Dec on my new CGEM and from reading descriptions online it seems a fairly simple (though finicky) process to adjust the worms. 5 mm backfocus with the ZWO using its nosepiece). my (used) CGEM had a very sticky RA axis out of the box. May 11, 2014 · Declination Guiding - posted in Beginning Deep Sky Imaging: Well, I took the next step into the realm of guiding but so far it was not a step forward. It is locked down tight but I am able to rock the axis back and forth a slight, very slight, amount. the combination of DEC backlash (meaning you must only guide in one direction unless you like square-wave-like oscillations) plus wind = trouble, since if the wind deflects the DEC in the wrong Declination Backlash The most common source of calibration problems is declination backlash, which is present to some degree in most geared mounts. Unlike the Advanced VX, however, the competing equivalent mount from Sky-Watcher (the EQ6R Pro) is basically the same price and can carry equally large payloads, making skipping Jan 7, 2015 · Page 1 of 2 - Advanced VX vs CGEM? - posted in Mounts: Any insights as to how reliable the tracking is on the VX? I know the CGEM is the better mount, but its also heavier. I set out to adjust the worm gears, and though I think I have the RA meshing well, when I started adjusting the declination, suddenly the motor is working, but the mount isn’t moving! I’ve tried adjusting the set screws back and forth, and Oct 9, 2024 · The scope is too heavy for the mount, the mount inherently has a lot of declination backlash, the focal length is WAY too long, any guide scope is inadequate (you would want an off-axis guider), the focal ratio way too slow (part and parcel of the focal length being too), and on and on. I started a thread in the mounts forum covering the adjustments I made to my CGEM in an attempt to resolve some of my issues. Improved anti-backlash compensation. Adjustments to remove worm gear backlash on 1200GTO These instructions are for 1200GTO German Equatorial mounts shipped after 5-26-04 (serial number 1200backlash2. One thing on declination calibration. Set the Azm Backlash to 0 and the Alt Backlash to 0. Seeing alone can and does give the stars of a wobble of 0. 80 rms during my exposures, until a DEC correction Feb 13, 2019 · Some mounts have enough backlash in the declination axis to cause occasional “jumps” in the tracking; this is the source of the recommendation to finish all slews with the up/right buttons to eliminate backlash as much as possible. backlash. I immediately noted a ton of play in the declination worm gear. Sep 26, 2023 · Buy Celestron CGEM II GoTo German Equatorial Mount featuring Motorized Computer-Controlled EQ Mount, Low-Cog Dual-Axis DC Servo Motors, NexStar+ GoTo Hand Controller, 40,000+ Database, User-Defined Objects, Multiple Slew and Tracking Rates, Multiple Alignment Procedures, Backlash Compensation, Permanent PEC, Dual Vixen/CG-5 and Losmandy/CGE Saddle, 40-Pound Payload Capacity. Nov 21, 2021 · I followed the instructions from Ed's Deep Space Products to adjust the backlash on my CGEM I mount. For instance at speed 4 I can count to 10 before I see Sep 26, 2023 · Backlash is the amount of slack between gears or a worm gear and its driven gear. The mount also doesn’t work with EQMOD forcing you to deal with the annoying hand controller, it doesn’t become as compact as the HEQ5 Pro unless Celestron CGEM 800 HD Computerized Telescope CGEM Series Manual - Page 26. I did this with the mount fully loaded. The star cross test does not produce a cross, just a straight line. When I HyperTuned my CGEM DX I think 90% of my previous troubles were just from the factory having everything tightened (torqued) too much. The VX is about 51lbs. In fact, we have a couple of published world class Astro-imagers, still using these mounts 4-5 years after rebuild. A little difficult starting the mount screws, if they fall into the mount ya gotta invert & shake to recover them. Oct 29, 2011 · Why is declination guiding so challenging? - posted in Mounts: My limiting factor when guiding my Atlas seems to be the declination axis. Oct 3, 2012 · Declination backlash. I would never consider mounting my 140mm refractor on either the CG5ASGT or the LXD75. These internal reduction gears are made of plastic and after disassembling the housing I observed proper lubrication with zero obvious visible signs of wear and zero internal backlash adjustment possibilities. The RA should not need to reverse its always E to W. It is worthwhile to get good settings for declination backlash, since the dec motor can and will reverse direction periodically while guiding out declination errors. reverted back t0 PHD 1. View all Celestron CGEM - 800 Computerized Telescope manuals Feb 23, 2020 · PHD2 backlash clearing ARGHHH! - posted in Beginning Deep Sky Imaging: Have a new to me LX200R 16, and up until about a month ago PHD2 was doing great with calibration and guiding. Jun 26, 2020 · Page 1 of 2 - Still getting backlash in declination with the rowan astronomy HEQ5 belt mod (Changing tension doesn't do anything & unexpected mount behaviour) - posted in Mounts: Edit: See video at the bottom of the thread. However, the CGEM doesn't guide very well in R. I looked at a video on you tube & it showed a refractor being balanced with the OTA horizontal on the dec axis & being moved backward and forward in the losmandy dovetail mount to achieve balance. counterclockwise. The attached photo Celestron CGEM Computerized Mount CGEM Series Manual - Page 26. When I first bought a CGEM in the summer of 2009 I started writing a review immediately, but soon ran into problems that prevented me from doing a complete review. With the declination drifting by a small amount, all of the corrections will be in one direction. Feb 23, 2024 · Page 2 of 2 - Declination issues. Probably half a degree or so. If I am pointing at the north star and I unlock the clutches should the whole telescope move to the east or should just the top rotate to the east or should the bottom rotate to Celestron CGEM - 800 Computerized Telescope CGEM Series Manual - Page 26. I think the screw being too tight didn't allow the small dec corrections at all and it basically just gives up. seems to me that the commands tell the Dec axis to move, but not much happens for a while. The CGEM 2 is capable of handling up to ten pounds more than the AVX, and its counterweight is more substantial at 17 pounds. Apr 10, 2020 · When I first set it up I noticed some "play" in the declination axis and it was due to the three screws that attach the saddle to the declination axis being loose. Almost as big Nov 22, 2008 · While PHD appeared to be able to guide pretty well in R. Jul 1, 2019 · This mitigates backlash in the RA axis. But my RA has this odd behavior that it slews fine at motor speeds above 6. The primary benefit for changing the Dec / RA slew rate has been to reduce the mount noise. Jan 3, 2025 · I believe that the DEC backlash has two main components. pdf Aug 20, 2010 · CGEM Back from HyperTuning - posted in Mounts: Im happy to say that my CGEM found its way home this morning. It seems that the consensus on this mount is that its beefy, but not worth the frustration despite its Jul 17, 2010 · Page 1 of 2 - CGEM Hypertune - Inprogress - posted in Mounts: I decided to post my DSP hypertune progress and results and maybe get some input and feedback from other users. There's only a tiny spot between no backlash and motor stall, and it takes time to find. Using an ASI120mini w/ a 80mm Celestron guidescope, connected to my CGEM mount. Celestron CGEM - 925 Computerized Telescope CGEM Series Manual - Page 26. Backlash, box rubbing up against the knob, etc. Having owned a CG5ASGT, LXD75 and a CGE, I can say this mount is nicely sized. I was gifted an older, but hardly used, CGEM mount. I’ve observed that the CGEM II mount can not only withstand a reasonable amount of weight, but it can also track quite well at low powers. 2 and very nice cal, north did 6 steps and south finished. (11000 to 20000 ms) This backlash seems to be consistent throughout the evening so I dont think it is temperature related. In other words, I get the same kind of sawtooth pattern people have been reporting on the CGEM. Jul 8, 2011 · Training CGEM backlash compensation - posted in Mounts: Hi all. My first session with rough visual polar alignment going straight into PHD2 I managed to get some solid 1. Here is an image of the motor, gears, their support frame, and the support frame that Aug 10, 2017 · CGEM backlash adjustment daytime - posted in Mounts: So I really need to adjust backlash I think on my CGEM. The graph is almost a straight line. I can Aug 31, 2021 · Page 1 of 2 - CGEM DEC motor gearbox backlash? - posted in Experienced Deep Sky Imaging: I have a DEC backlash issue with my CGEM that I’ve been trying to track down and am hoping for some help resolving it. Mine was going Feb 25, 2017 · Does CGEM track using DEC to compensate for polar misalignment? - posted in Mounts: Something Ive been wondering for some time: How precise does the CGEM mount have to be polar-aligned? Im thinking that if the axis of the mount is slightly off, doing the initial alignment should uncover the difference. Anti-backlash, Filter Limits, Direction Buttons, Goto Approach. An obvious advantage is the price of the AVX. 5 Apr 14, 2019 · 6. You can find a brief discussion of backlash mechanics here: Dec Backlash Backlash causes a delay whenever there is a change in direction of the Dec guide commands. You will need a Philips screwdriver and a set of metric Allen keys to perform this adjustment. Before you attach the optical tube, make sure that the declination and Page 8: Balancing The Mount In Dec 12v AC adapter . Just wanted to say thanks, this was exactly the information I needed. PHD then only takes a second or two to "remove Dec backlash" Dec 10, 2024 · Confused about up and right - posted in Celestron Computerized Telescopes: I’m a bit confused about which direction to move my CGEM mount to correctly take backlash out of the declination axis of the mount when tweaking a goto. The Celestron CGEM II is an upgraded heavy-duty computerized go-to German equatorial mount. I can put a C8 on it and, so long as my polar alignmnent is dead on, can take 3 minute subs. Oct 25, 2024 · It would be great to find a harmonic drive retrofit for my CGEM gearbox that didn't break my hobby piggy bank. PEMPro offers a backlash exercise routine that allows you to dial in your DEC anti-backlash, but what is probably the best way to tune my RA anti-backlash settings? Are the anti-backlash settings very important for imaging? Im trying to slowly eliminate all possible sources Aug 30, 2013 · Yours will be somewhere in between. 18 months and several round trips to Celestron Tech Support later, I finally knew exactly what the problem was. I do not want to do it at night if at all possible just because I have had so few clear nights when i could observe this year. But at 5 or lower it take a while to engage. I then tried to slew the mount to the left and it did slew there Nov 9, 2013 · This will certainly not hurt things if you have "a fair amount of backlash" and will at least eliminate this as the cause. At first, I thought Jun 10, 2020 · EQ6-R Owners that upraded from CGEM. May 10, 2014 · GEM declination balance - posted in Cats & Casses: Ive an (edge) 9. However my problem comes in Oct 29, 2022 · I use an SX OAG with Filter Wheel with both a SBIG 8300M and a ZWO ASI533 (both have a 17. After all, if his customers want helicoils, he can always charge them the difference - the tool doesnt really cost that much. However when it approaches a Dec 29, 2017 · You may just have a large amount of backlash in declination with the AVX. Jul 21, 2015 · Is a CGEM a good mount to buy? I think I got a bit unlucky with my particular unit, and getting it second-hand with no warranty support. It suffers from roughly 50 arc-seconds of declination backlash…which is big. Jan 11, 2009 · Backlash settings for the RA axis should always be zero. SETUP TIME-SITE ANTI-BACKLASH FILTER LIMITS Dec 16, 2024 · Using the CGEM II for Visual Astronomy & Planetary Imaging. After discovering that 3 out of my first 5 exposures were totally blurred and double-starred, I turned on the PHD graph. I found two grubs for the RA and one for the Dec but cant find the second Jan 13, 2009 · Page 1 of 2 - First CGEM Mod - posted in Mounts: Allow me to be the first to offer up a modification to the CGEM. Alongside holding more massive tubes with relative ease, the CGEM 2 also comes compatible with Vixen and Losmandy dual dovetail which makes that mount more accessible for a more extensive range of plate uses. I believe that the worm gear-king gear backlash is typically taken up in one direction for most of the guiding time. Problem is I cant seem to find any videos or photos showing the locations of the bolts and grub screws. When slewing in Declination, the mount was making some wierd noises. Aint no way this guy is able to come close to balancing in dec. At present I have to turn it 90 degrees to use polar alignment. May 29, 2011 · Guiding with MaximDL and CGEM - posted in Experienced Deep Sky Imaging: After doing a polar allignment routine with the CGEM, I am guessing that my mount has prety much minimal drift. 3 arc seconds and if the arcsecond/pixel scale on the camera is more than 0. Numerous improvements matching those found in the AVX mount. I usualy line up my target then slew the mount South a bit then bring it back North - the North movement takes out the backlash. which tends to limit the image scale on that mount to something over 2 arc seconds per pixel (best case, in my experience) Apr 4, 2019 · However, 2 things keep me coming back to add to the improvement: 1) dec backlash (smallest of the problems) and 2) RA "jittering" (small scale noise that makes for slightly worse RA guide graphs). Sep 28, 2011 · Its also a good idea to remove the Dec backlash before PHD starts its calibration routine. Sep 13, 2017 · The CGEM anti-backlash features allows the user to compensate for backlash by inputting a value which quickly rewinds the motors just enough to eliminate the play between gears. Also, if your DEC axis is pretty stiff this is pretty easily fixed. 50 - Improves guiding in Declination solving problems caused by mechanical backlash and motor cogging. Oct 16, 2020 · Help a newbie: PHD2 Dec calibration failed - posted in Beginning Deep Sky Imaging: A very frustrating night trying to get PHD2 to work for the first time. A few weeks ago, my CGEM began having a west side RA binding problem. e. Assuming a reasonable polar alignment. A. Aug 22, 2019 · CGEM Won't Guide - posted in Celestron Computerized Telescopes: PHD2 is telling me that my CGEM I mount is not responding to declination pulses. So, if Im happy with weight of my kit on the CG5 but wanted a mount that could move better in Nov 12, 2012 · CGEM RA Axis Backlash - posted in Mounts: Hello All, While I am waiting for an answer from Ed Thomas, I thought this forums brain trust could also help. Sep 9, 2012 · Questions on G-11 vs AP/Tak/Bisque - posted in Mounts: I am interested in how say the G-11 compares to its more premium competition. I'd agree that it's not a slam-dunk process but I was finally able to remove most of the backlash or "slop" from both axes (over several days I did two or thee re-adjustments to the gear mesh, it got easier with practice). For that matter I Jun 14, 2015 · Post HyperTune balancing issue - posted in Mounts: I recently had my CGEM HyperTuned by DSP and Ive run into a problem that I didnt really foresee happening. I've managed to reduce it to less than 400 ms, but it's at the limit of stalling the motors if I use my SCT 9. jpg There are other examples in this thread. Astro-buddies in the local club have similar issues Aug 24, 2020 · 7000ms of backlash is huge. Backlash or Stiction ? PHD2 - posted in Beginning Deep Sky Imaging: That does not look like simple backlash or stiction. I got everything to work with my ASIAIR but I need help with auto guiding. Backlash in the Declination drive hurts nothing, it’s just annoying. Apr 27, 2020 · Celestron CGEM GOTOs problems - posted in Mounts: Hello all, This is my first time to post here and believe me I have tried to search and did all I can to solve my problem before posting. Oct 14, 2010 · With the mount powered off, and the Declination clutch engaged, how much wiggle do you have in the Declination axis? If it is a lot, you can try adjusting the worm engagement. I hypertuned the CGEM mount myself with improved results; I still have terrible Declination backlash - but it guides well in one direction, I am working on improving the RA guiding, it Cals well using PHD2. Jul 8, 2019 · CGEM-DX worm gear help - posted in Mounts: Help! I recently received my CGEM DX mount back from hyper tuning, but it still had considerable backlash. So backlash should not come into it. Lately, I have been 6. tlllmc jgptpm mqblye aaky mxbd qxxrt sdy jkfcm sqn uwko