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Re: Stiff RA axis on brand new GM811G
Neverfox:
The RA never does swing completely freely as there is a fractional inward vector force of the downward weight of the mount pressing on the clutch. The wavy washer helps but does not eliminate it. This is normal. If you want the best free wheeling motion, you can crank the altitude down to near zero and make the RA axis horizontal (careful you don't tip over!). That way you have minimal pressure on the clutch disc. This is a pain since your lose your latitude setting and you need to redo polar alignment. If you never change your rig setup this could be a way to go. The Losmandy video shows the Titan mount which may be a bit different. My G11G never rotates that freely. But if you just loosen the the clutch knob and go for telescope east heavy (this is for the Northern Hemisphere), this should be sufficient. By swinging RA lightly with your hand, you should be able to see where it feels the best. But never a free swinging motion like some other mounts. |
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Re: Stiff RA axis on brand new GM811G
Sonny Edmonds
My GM811GHD was "sticky" like that as well when brand new. The Wavey Washer fixed it.
One of the biggest improvements I made was when I installed the on my 811. I have to move most of my mount out, and back in, each night that I use it. (which is a LOT!) If the weather is going to be clear, I leave my tripod set-up, covered, and it stays near perfectly aligned. (But I always PA, and build a new model.) But the RAEXT allowed me to make "Chunks" out of my mount. In doing so, my balance weight (1 - 11 pound) stays where it is on the CW shaft bar, and the whole Dec axis with the CW is one sub-assembly. So it is in balance when mounted to the RA. My telescope assembly, likewise, is a "chunk" that when it mounts in my saddle I have a ?clamped as a stop that indexes my D-bar in the clamp and it lands in balance every time. The DVA is underhung on my , and it stops against the front of the clamp. By doing this, dismantling and reassembling my mount all the time has become a breeze, and it assembles in balance each time. (When I have checked it, it is boringly in balance!) Incidentally, I balance mine with my wiring harness attached so it is factored in to the over all balance. (I'm also the guy who uses a digital level to make sure my tripod is plumb to the Earth before assembly. ;^) ) -- SonnyE (I suggest viewed in full screen) |
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Re: Stiff RA axis on brand new GM811G
Brian,
Thanks. I tried the lower altitude trick and that gave me a less sticky experience on the stickier side (while actually making the less sticky side more sticky). In any case, I was able to get enough free movement that I could find a balance point I believed. So as long as what I'm experiencing isn't abnormal, I'm satisfied. It's a little frustrating to have to take the mount out of the usual altitude setting if I need to rebalance, but hopefully a few pieces of tape will work more often than not. FWIW, before trying the hack, I did make just to demonstrate how sticky it was at first, which seems a lot more than the mount in the Losmandy video. |
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Re: Gemini2 HC touch screen problem
Did you try plug the HC into the other serial port? ?Remember to increase the baud?
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Re: Gemini2 HC touch screen problem
Hello Brendan, Thanks a lot for the response. I opened up the HC again and checked for anything pressing. I tried to use the display without the cover and still the same issue. SD card is okay and I cleaned up the connections. Nothing seems to change the behavior. Regards Hemant On Mon, Dec 28, 2020 at 3:47 PM Brendan Smith <brenatlilydale@...> wrote:
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Re: Stiff RA axis on brand new GM811G
We have a video that covers how to balance the mount along with additional balancing tips (watch to end): On Mon, Dec 28, 2020 at 1:54 PM Paul Goelz <pgoelz@...> wrote: On 12/28/2020 3:32 PM, neverfox@... wrote: --
Brian? Brian Valente portfolio |
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Re: Stiff RA axis on brand new GM811G
On 12/28/2020 3:32 PM, neverfox@... wrote:
With the clutch knob loosened, the axis doesn't swing freely like I've become accustomed to with other mounts.and..... seems to be on older mounts not fitted with a wavy washer, but mine has said washer. Is what I'm experiencing normal or should I be reaching out to Losmandy? If it is normal, how do I balance in RA with that much tolerance?I'll let Brian weigh in on whether that is normal or not. However, my new(ish) GM811 is the same. The RA axis never becomes fully free like the DEC axis. To balance, I just nudge RA in both directions with the clutch fully loose and see how long it coasts after I let go. Adjust the counterweight until it coasts about the same in both directions for the same amount of force. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com |
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Re: Gemini2 HC touch screen problem
Hi Hermant
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Stiff RA axis on brand new GM811G
First of all, glad to be part of the group, as I just received my GM811G today, which is also my first Losmandy. Everything is set up but I'm a bit perplexed by the RA axis.
With the clutch knob loosened, the axis doesn't swing freely like I've become accustomed to with other mounts. I can pretty much get it to stay put in any position unless I move the counterweights a good deal. I can move the weights 4-5 inches with no apparent change in the balance. That just doesn't seem right to me as I'm not sure how I would verify when or if I've actually achieved proper balance. I have about 25lbs of payload and two 11lb counterweights (works with one, but it just ends up further down the shaft and doesn't change what I'm describing). I've come across mention of this issue when poking around but it always seems to be on older mounts not fitted with a wavy washer, but mine has said washer. Is what I'm experiencing normal or should I be reaching out to Losmandy? If it is normal, how do I balance in RA with that much tolerance? |
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Gemini2 HC touch screen problem
Hello all, I am facing a strange problem with my HC touch screen. Center left part of the screen does correctly respond to touch. Touching that portion of the screen is recognized as touch towards the center of the screen. Attached is an image that shows?response of touch screen along all four edges. Top, bottom and right edges seem fine but left edge shows?a strage D shaped response. Calibration, reflashing the firmware, resetting SRAM, nothing works. I opened?the HC up just in case something was pressing against the screen but that doesn't seem to be the?issue as well. The behaviour is very consistent and does not change at all. My guess is that this is a problem with the touch screen itself. Has anyone else faced this issue? Anything I can try before considering a replacement? I see that that touch screen is a part of a blue screen display board from thaieasyelec. I can't find a replacement for the board. Not sure if I can change out the touch screen overlay - seems to be a few dollars from ebay but not sure of the compatibility. Any suggestions? Regards Hemant |
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Re: ES Losmandy G11 RA Backlash
Mark. Thanks so much. In my ignorance I have maintain the clutches fairy tight to help with unloading and setting up. I had no idea I could damage the Mount. Thanks again and I¡¯ll keep them very loose from now on. ?Tom --- mjcw500@... wrote: From: "Mark Christensen" <mjcw500@...> To: [email protected] Subject: Re: [Losmandy_users_io] ES Losmandy G11 RA Backlash Date: Sun, 27 Dec 2020 18:21:57 -0800 Persons Coverdale, By locking the clutches (including when person-handling the mount in and out of the boxes) you are taking an unnecessary risk of damaging the AL worm. I once saw a cheaper (poor quality cast gears) mount shred a section of its worm wheel (aka ring gear in some quarters) when the user hefted it with the counterweight attach. An extreme case but an extreme result. You may get lucky on any give trek and you may not. Why take the risk in the future? Mark C. |
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Re: ES Losmandy G11 RA Backlash
Persons Coverdale,
By locking the clutches (including when person-handling the mount in and out of the boxes) you are taking an unnecessary risk of damaging the AL worm. I once saw a cheaper (poor quality cast gears) mount shred a section of its worm wheel (aka ring gear in some quarters) when the user hefted it with the counterweight attach. An extreme case but an extreme result. You may get lucky on any give trek and you may not. Why take the risk in the future? Mark C. |
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Re: ES Losmandy G11 RA Backlash
hmm I don't see the calibration prior to the GA run, but it looks to me like you may have had an orthagonality?problem there Towards the end of the log the long guiding runs look pretty good, you're only .05 pixels difference between the axis. I think RA needs to be more responsive, so a faster guiderate 0.5 or higher would probably do it On Sat, Dec 26, 2020 at 7:47 PM Sunil Bhaskar Bhaskaran <cyclops12321@...> wrote:
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Brian? Brian Valente portfolio |
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Re: ES Losmandy G11 RA Backlash
Brian,
?
? ? ? ? ? ? ? ? I wanted to share the screen so that you can have a better idea as to why I had chosen the numbers for guiding :D. I am attaching the phd2 log during which I ran the guide assistant. As for the guide speed the phd2 wizard automatically chose this value. I had good success with .4x speed but will try out .5 tonight and compare results. One small change was observed by me today morning - even after almost eliminating DEC play the mount seems to have? developed significant DEC play now. Is it possible that weather caused some compression or something? It did get chilly yesterday. I had just to change my exposures in phd2 from 2 to 3 and vice versa as the moonlight or something was really blowing up my stars. Only reducing the duration managed to help me atleast guide the mount little bit.
?
Sunil
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Re: ES Losmandy G11 RA Backlash
Hi Sunil Ah - i did not see a guiding assistant run there Screen captures aren't useful for analysis, if you can upload the log that included the GA run that would be great. Are you sure the log you previously uploaded was after this? The exposure time i saw was 1 second. Based on your previous log you uploaded, RA was performing under what you set for min move and there was no backlash compensation applied, so all the things I mentioned are still valid recommendations. also I would say your guidespeed is too low at 0.4x - you want to be at least 0.5x or higher Guiding Assistant is sometimes just a guideline, and in your case if you are looking for guiding better than what it recommended, you will need to tweak those settings On Sat, Dec 26, 2020 at 11:24 AM Sunil Bhaskar Bhaskaran <cyclops12321@...> wrote: Brian, --
Brian? Brian Valente portfolio |
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Re: ES Losmandy G11 RA Backlash
Mark, ?Your comment on Sunil having is clutches unlocked to transport got me?to thinking. I transport my G-8 into the Mojave Desert for?Bortle 1/2 imaging and never do anything to the clutches. Am I risking damage to my drive trains or anything?else by not releasing the clutches? The entire mount is a foam and?plastic box latched tightly shut. Thanks Tom? --- mjcw500@... wrote: From: "Mark Christensen" <mjcw500@...> To: [email protected] Subject: Re: [Losmandy_users_io] ES Losmandy G11 RA Backlash Date: Sat, 26 Dec 2020 07:08:53 -0800 Sunil, First reaction is that RA backlash should never matter when guiding: The scope should be slightly heavy eastward and the guide rate should be less than 100%. That way the RA never reverses and hence backlash is a complete non-issue. To debug the problem I suggest you turn off dither along with any other "feature" - when diagnosing problems the simpler the configuration the better. It may be the fact that you have dither turned on for both axes that is causing RA backlash to show up. Second reaction is, have you tried readjusting the RA worm? That needs to be done with the motor removed while rotating the worm by hand so you can see and feel what is going on. The worm wheel (large gear attached to the axis) needs to go through the full rotation so that you don't bind on the (unknown) high spot on the gear. Third reaction is, I hope for your sake than when you shipped it the clutches were loose! Best Wishes, Mark Christensen |
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Re: ES Losmandy G11 RA Backlash
Brian,
? ? ? ? ? ? ?All the values entered in the toolbar(except the Hysterisis) was recommeded by phd2. The one thing I gotta mention is that the weather here is a bit hazy so I was taking longer duration guide pulses (2s - 3s) I believe.I have enabled backlash compensation and ran guiding assistant. I am attaching calibration and guiding assistant info as well. |
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Re: ES Losmandy G11 RA Backlash
Mark,
? ? ? ? ? ?Appreciate the responses. The truth is I have been battling this issue for the past 8 months when I couldn't use the mount at all. Before that it functioned well. Not this bad. To answer you questions :? 1)RA Backlash : I apologize for the wrong methodology . I was referring to the worm wheel an the worm block wiggle. No matter how much I tighten, there seems to be movement when I wiggle the counter weight shaft. There is no DEC play but there is severe RA play. 2) I have tried adjusting but these seem to be very different from the traditional G11 worm blocks. No offence but the Gemini 2 ones look way better and sturdier than the one I have. The worm cover is just that - a cover. I I have seen videos from the Losmandy channel in youtube but the motor assembly is very different. While Gem2 is servo mine is stepper.WHen I tried to remove it, something was preventing it from coming off. Do I need to loosen the couplings which connect the motor to the worm mesh? 3) The mount worked fine for a while. But being in a humid and ununsed state took its toll I guess. The lube inside had solidified and I had to relube everything except the worm wheel. |
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Re: ES Losmandy G11 RA Backlash
HI Sunil Here's my observations from your guidelog looking at your two longest runs 1. your settings are not very optimized for your conditions and equipment. your min move on RA is too high, it's at 1" and you are guiding at 0.82" so i'd say for that min moves your guiding is where i would expect it. Run guiding assistant and/or set that value lower 2. your seeing looked less good in the second long run (segment 11), i think your exposure time should be longer to even that out - maybe 2.5-3 seconds 3.? you should enable dec backlash compensation in PHD which will clean up your DEC guiding. a guiding assistant run should make a recommendation there, but if not i would start with 800ms with a max of 2500ms and let it adjust itself 4. after tightening up min mov in RA (and DEC too), if you still need better guiding results you can try predictive PEC algorithm for RA. i'd set the period to 239.9 and disable auto adjust period.? that should be a good start On Sat, Dec 26, 2020 at 5:16 AM Sunil Bhaskar Bhaskaran <cyclops12321@...> wrote: Hi, --
Brian? Brian Valente portfolio |
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Re: ES Losmandy G11 RA Backlash
oop sorry i see it here in the op let me look at it On Sat, Dec 26, 2020 at 5:16 AM Sunil Bhaskar Bhaskaran <cyclops12321@...> wrote: Hi, --
Brian? Brian Valente portfolio |
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