Re: Gemini-2 momentarily went haywire
Very special skill, tools and techniques are required to remove a large scale chip on a multi-layer circuit board and if the board traces are damaged there will be new problems to solve.
A more like problem other than all those already mentioned is a microscopic crack at a connection point on the board or a cracked circuit trace. ? ?
When I worked on Large Scale computer systems long ago we used circuit coolant on isolated surfaces of a circuit board to locate solder cracks. ? ?Chill your controller in the refrigerator and repeat your trouble shooting process. ?Replacing a chip is extreme and the very last step. ? Currently I work around ?literally hundreds of SOC and surface mount components and never had a chip failure so look elsewhere. ? ? ? ??
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Re: Reducing DEC Backlash with Titan 50
Thanks, guys.
Paul:
Your write-up on adjusting the worm mesh is basically what I was doing with those bolts.... a tad of torque on the wing bolts, and I get the noise.? Back off just a little, but not totally loosened, and the sound goes away.
I would like to attempt to lubricate the worms.? My questions would be:
1.? I have a heavy scope.... C14 Edge.... do I need to remove all equipment from the mount to remove the worm gears?
2.? I think Scott has a video on greasing a worm, but it looked like it was on a G11.? Are there other sources to look at?
3.? Is it basically that I remove the worm block bolts to remove the worm housing block, and open it up?? I'm assuming the end cap needs to be removed.
4.? I think Scott was saying to use alcohol to remove old grease, and then apply new?
5.? Just re-assemble, and adjust the mesh (play with the block bolts again)?
Thanks a lot for your help.
Dan
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Re: Losmandy G11 Gemini 1 Battery
I certainly can see the benefits of monitoring current and volts for the Gemini?
--
Brendan
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Re: Reducing DEC Backlash with Titan 50
OK, what weight amount should I use? Do you do a final balance after adding that weight? ? Aubrey ? Sent from for Windows 10 ?
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From: Michael HermanSent: Sunday, May 9, 2021 9:54 PM To: [email protected]Subject: Re: [Losmandy_users_io] Reducing DEC Backlash with Titan 50 ? Aubrey, that is the great benefit of the hanging RA cord.? Hanging the cord and weight off to the East experimentally gives the lowest vibration (chatter) to the RA ring gear (worm wheel) as it is driven to the West by the worm.? ?? The torque on the RA axis is identical no matter what the RA position is or the Dec position.? It is the same torque regardless if meridian flip. It is the only way to get the torque to be uniform.?? Give this a try....and see for yourself.? I was quite skeptical and didn't believe it til I tested this method.?? ? Thanks Michael, but its not clear how this works on both sides of the meridian. I am also operating remotely so everything has to work without dragging, snags etc. ? Aubrey ? Sent from for Windows 10 ? ? Aubrey, To maintain a constant torque on the RA axis, which is what you are seeking, you need to use a weighted cord wrapped around the RA axis.? Using an unbalanced counterweight rod the torque will vary as the RA axis rotates.?? You put that hanging weight on after your counterweights are balanced.? I am using 1 pound weight....I had tried 7 pounds earlier.? I'm not sure what is an optional weight to use.? My scope is a C14EdgeHD.? ? Here is a way I implemented on my Titan RA.? I hope the photos are clear enough.? The weight hangs to the East and always provides an Eastward torque.?? ? ? Thanks Michael for the comments. Fortunately at this time I only have one issue. That is when I am starting out in the lower east imaging, I have nice round stars with 10 min subs. But as the Counter weight Shaft and weights begin to pass the 45 degree angle, I begin to have more flattened stars. As it gets closer to the Meriden I get round stars again. I think I might have too much east bias on the weights. I am getting about 1+/- Arcseconds PEC when guiding. But I have to use the onboard PEC function. I have noticed that if you want good results with the G2 PEC you pretty much have to run it on each target as you begin each DSO. If you do it that way it will work on both sides of the Meriden. I use Maxim DL 6. for guiding and an SX Superstar. My Telescope is the AT 10¡± RC with CF Arms and shroud and 60 mm guide scope so I am caring about 50 LBS load with my heavy camera. ? Aubrey ? ? Sent from for Windows 10 ? ? Aubrey, It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.?? You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!?? Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing). Have fun,...get some nice images! ? Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
Dan,
The lube on the Titan ring gear needs to reduce the worm friction to as low as possible.
My research on the "4-ball test" and the " Timken load" test shows the ?"CRC Brake and Caliper Grease" has the lowest scar length (0.6mm) and largest Timken load (50 lbs) vs the others I checked (Shell 33 and 64 and Arctic Jetlube and Superlube). All if these have the same rating for copper corrosion..."1B" meaning shiny (that's a 100C 24 hr test).??
Put try that CRC grease on your Ring gear and worm gears on your Titan and see if it eliminates your noise trouble.
Best, Michael
On Mon, May 10, 2021, 6:21 AM Paul Kanevsky < yh@...> wrote: Hi Dan,
Glad to hear you're making progress with backlash!
The sound appears to be caused by too tight of a mesh between the worm and the worm-wheel. Very tiny variations in worm and wheel can lead to increased binding which results in the occasional whiney noise. Also double-check that everything is well-balanced, the mount may be struggling under uneven weight distribution.?Here's how I adjust the worm mesh on a Titan (originally posted here /g/Losmandy_users/message/50534):
1. Loosen both of the wing screws on the axis you are adjusting
2. Loosen slightly one of the large bolts holding the worm assembly underneath and push the whole assembly very slightly out, away from the gear.
3. Try moving the motor with the HC to see if the axis now moves freely, without stalling or binding. If it doesn't, move the whole worm block even further out. Very little movement is needed here.
4. Once the motor is moving freely, tighten the large bolt but not excessively, enough so that the worm block can still be pushed with some force.
5. Test the motor again with HC. If it binds now, repeat steps 2-4 moving the worm slightly further out
6. Now, tighten both wing screws by the same amount, just enough so that they are not loose anymore, only until you feel some resistance
7. Test that the motor rotates freely. If not, go back to step 2 and try again.
8. Now, check for backlash. If there is too much, tighten the wing screws a 1/8 of a turn more, rotate both screws by the same amount. They should be harder to turn, as they are pushing the worm block closer to the gear, against the friction caused by the large bolt
9. Repeat steps 7 and 8 until just a little backlash is left.
10. Tighten the large bolt, but don't overtighten. When final tightening this, it can push the worm just a bit closer to the worm. If there's no more wiggle room, it can cause the worm to bind. I usually leave a little more backlash than I'd normally like at this point, so that when I tighten the large bolt, it takes up some of the remaining slack.
This usually takes about 5-10 minutes, and my adjustment is good for a year or two.
Regards,
? ?-Paul
On Mon, May 10, 2021 at 07:56 AM, <dkfcpalfd@...> wrote:
Paul:
Last night I cranked up TVC in G2.... up to 100.? Ran the GA, and I couldn't believe it, there was no backlash shown on the graph, in fact the actual plot was very close to and slightly left of the ideal curve.... I've never seen that before.? PHD2 told me I have no backlash, and no compensation is needed.? Amazing!!!
You were right, in that if I left TVC at 100 and tried guiding, the DEC guiding error was all over the place.? I cranked it down to 5 and it was still pretty rough, so I turned it down to 1 and that looked pretty good.
I also had been trying to calibrate a trial version of SkyGuard from Innovations Foresight.? Previously, I could not get it to calibrate, it was telling me it did not see enough movement on the Y axis.? That made me suspect DEC backlash.? So, with TVC set to 100.... it calibrated immediately, no problem.
At this point, I'm going to leave DEC Comp turned off in PHD2, and only apply TVC based on how my DEC guiding error appears.
I have only one more question:? Listen to the noise as I slew in DEC in the attached video file.? It only appeared after I started playing around with the DEC block bolts.? The noise seems to disappear if I loosen the wing bolts on the DEC block.? I thought I had it gone completely after installing the plastic shims, but it came back again last night.? I stopped the slew, loosened the wing bolts, and it disappeared.
My questions would be:? Is that noise indeed caused by improper adjustment of the bolts on the block?? Is the mount harmed potentially when that noise is happening?? What's the strategy for tightening those bolts?? I have the allen head bolts underneath backed out slightly, and use the wing bolts to tighten things up.? Too much torque on those wing bolts, and I hear that noise, or I get stalls.? Too little torque on the wing bolts, and I get noticeable play when rocking the scope back and forth by hand in DEC.? It seems like I have to have virtually no torque on the wing bolts..... stop turning when you feel it stop turning when tightening.? Is that OK?
Thanks so much.
Dan
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Re: Losmandy G11 Gemini 1 Battery
Hi gang,
As a simple temendy for Enol, just reduce the maximum slew rate.? There is a digital setting for that.?
If Enol's system runs out of current as the counterweight shaft moves toward horizontal, the problem is it is unbalanced.
________
An ammeter on the Gemini input is very useful.?
Without it you cannot determine the cause of the high current draw.? It could be one or more of:
a. Imbalanced scope load
b. Jammed worm gear
c. Bad wornout motor
d. Un-lubed worm or needle bearings need cleaning and re-lube
Best regards, and good luck, Michael
Yeah peak is a bit overrated mostly why¡¯d 200-250ma (if not less) at sidereal rate to 600ma slew?
but take into account both axes at this does so 1.2A peak.? It¡¯s hard to tell with digital readouts?
I run 3A @18vdc on a lab supply and it¡¯s perfect But also allow some variation for ¡°not all power supplies are equal¡±!
devices like the boost converter can handle 5A peak with good dissipation you can even parallel them
--
Brendan
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Re: Losmandy G11 Gemini 1 Battery
Yeah peak is a bit overrated mostly why¡¯d 200-250ma (if not less) at sidereal rate to 600ma slew?
but take into account both axes at this does so 1.2A peak. ?It¡¯s hard to tell with digital readouts?
I run 3A @18vdc on a lab supply and it¡¯s perfect But also allow some variation for ¡°not all power supplies are equal¡±!
devices like the boost converter can handle 5A peak with good dissipation you can even parallel them
--
Brendan
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Re: Losmandy G11 Gemini 1 Battery
On 5/10/2021 9:00 AM, Boreack wrote: Brendan, one question.
The manual of the G11 says you need at least 3 Amps to work propertly. I think this is for GoTo commands to work.
With your information, a GoTo only need 0.35 Amps at 17v, so 0.6 Amps at 12v. Something seems to be incorrect.
My actual battery supply 2.1 Amps max. With guiding, tracking, or one motor slew it work perfectly, but with a GoTo command at 800 velocity it start to move and suddenly stop.
Greetings, Enol. Just to add a data point.... I run my mount, two cameras and mini-PC all from the same 12V 5A power supply. I do not recall individual current draws but with everything running (and the imaging camera cooling), I never saw more than a total of 3A with the mount slewing. I know the recommendation is to use 17VDC but A) I don't see any need for more torque with everything balanced and B) running a brushed motor at higher applied voltage (and correspondingly lower PWM values to achieve the same speed) is harder on the brushes. Since slewing at full speed draws very little current (well under 2A in my case) I don't see the need for higher voltage. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: Losmandy G11 Gemini 1 Battery
Brendan, one question. The manual of the G11 says you need at least 3 Amps to work propertly. I think this is for GoTo commands to work. With your information, a GoTo only need 0.35 Amps at 17v, so 0.6 Amps at 12v. Something seems to be incorrect.
My actual battery supply 2.1 Amps max. With guiding, tracking, or one motor slew it work perfectly, but with a GoTo command at 800 velocity it start to move and suddenly stop.
Greetings, Enol.
Enol
.? Boost converter.? There are a lot of Chinese knockoffs on fleabay which have been known to fail.? Best you make your own.? The Ti data sheets and app notes are sufficient to build one but do use star ground return?
ive been thinking of doing one....just to try it.? I had the opportunity to test one.? It was excellent. I could hear the difference in the motors. ?
Cheers
--
Brendan
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Re: Reducing DEC Backlash with Titan 50
Hi Dan, Glad to hear you're making progress with backlash! The sound appears to be caused by too tight of a mesh between the worm and the worm-wheel. Very tiny variations in worm and wheel can lead to increased binding which results in the occasional whiney noise. Also double-check that everything is well-balanced, the mount may be struggling under uneven weight distribution. Also, make sure the worm is properly greased, dry spots can also cause binding.? Here's how I adjust the worm mesh on a Titan (originally posted here /g/Losmandy_users/message/50534):1. Loosen both of the wing screws on the axis you are adjusting2. Loosen slightly one of the large bolts holding the worm assembly underneath and push the whole assembly very slightly out, away from the gear.3. Try moving the motor with the HC to see if the axis now moves freely, without stalling or binding. If it doesn't, move the whole worm block even further out. Very little movement is needed here.4. Once the motor is moving freely, tighten the large bolt but not excessively, enough so that the worm block can still be pushed with some force.5. Test the motor again with HC. If it binds now, repeat steps 2-4 moving the worm slightly further out6. Now, tighten both wing screws by the same amount, just enough so that they are not loose anymore, only until you feel some resistance7. Test that the motor rotates freely. If not, go back to step 2 and try again.8. Now, check for backlash. If there is too much, tighten the wing screws a 1/8 of a turn more, rotate both screws by the same amount. They should be harder to turn, as they are pushing the worm block closer to the gear, against the friction caused by the large bolt9. Repeat steps 7 and 8 until just a little backlash is left.10. Tighten the large bolt, but don't overtighten. When final tightening this, it can push the worm just a bit closer to the wheel. If there's no more wiggle room, it can cause the worm to bind. I usually leave a little more backlash than I'd normally like at this point, so that when I tighten the large bolt, it takes up some of the remaining slack.This usually takes about 5-10 minutes, and my adjustment is good for a year or two.Regards, ? ?-Paul
On Mon, May 10, 2021 at 07:56 AM, <dkfcpalfd@...> wrote:
Paul:
Last night I cranked up TVC in G2.... up to 100.? Ran the GA, and I couldn't believe it, there was no backlash shown on the graph, in fact the actual plot was very close to and slightly left of the ideal curve.... I've never seen that before.? PHD2 told me I have no backlash, and no compensation is needed.? Amazing!!!
You were right, in that if I left TVC at 100 and tried guiding, the DEC guiding error was all over the place.? I cranked it down to 5 and it was still pretty rough, so I turned it down to 1 and that looked pretty good.
I also had been trying to calibrate a trial version of SkyGuard from Innovations Foresight.? Previously, I could not get it to calibrate, it was telling me it did not see enough movement on the Y axis.? That made me suspect DEC backlash.? So, with TVC set to 100.... it calibrated immediately, no problem.
At this point, I'm going to leave DEC Comp turned off in PHD2, and only apply TVC based on how my DEC guiding error appears.
I have only one more question:? Listen to the noise as I slew in DEC in the attached video file.? It only appeared after I started playing around with the DEC block bolts.? The noise seems to disappear if I loosen the wing bolts on the DEC block.? I thought I had it gone completely after installing the plastic shims, but it came back again last night.? I stopped the slew, loosened the wing bolts, and it disappeared.
My questions would be:? Is that noise indeed caused by improper adjustment of the bolts on the block?? Is the mount harmed potentially when that noise is happening?? What's the strategy for tightening those bolts?? I have the allen head bolts underneath backed out slightly, and use the wing bolts to tighten things up.? Too much torque on those wing bolts, and I hear that noise, or I get stalls.? Too little torque on the wing bolts, and I get noticeable play when rocking the scope back and forth by hand in DEC.? It seems like I have to have virtually no torque on the wing bolts..... stop turning when you feel it stop turning when tightening.? Is that OK?
Thanks so much.
Dan
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Re: Reducing DEC Backlash with Titan 50
Paul:
Last night I cranked up TVC in G2.... up to 100.? Ran the GA, and I couldn't believe it, there was no backlash shown on the graph, in fact the actual plot was very close to and slightly left of the ideal curve.... I've never seen that before.? PHD2 told me I have no backlash, and no compensation is needed.? Amazing!!!
You were right, in that if I left TVC at 100 and tried guiding, the DEC guiding error was all over the place.? I cranked it down to 5 and it was still pretty rough, so I turned it down to 1 and that looked pretty good.
I also had been trying to calibrate a trial version of SkyGuard from Innovations Foresight.? Previously, I could not get it to calibrate, it was telling me it did not see enough movement on the Y axis.? That made me suspect DEC backlash.? So, with TVC set to 100.... it calibrated immediately, no problem.
At this point, I'm going to leave DEC Comp turned off in PHD2, and only apply TVC based on how my DEC guiding error appears.
I have only one more question:? Listen to the noise as I slew in DEC in the attached video file.? It only appeared after I started playing around with the DEC block bolts.? The noise seems to disappear if I loosen the wing bolts on the DEC block.? I thought I had it gone completely after installing the plastic shims, but it came back again last night.? I stopped the slew, loosened the wing bolts, and it disappeared.
My questions would be:? Is that noise indeed caused by improper adjustment of the bolts on the block?? Is the mount harmed potentially when that noise is happening?? What's the strategy for tightening those bolts?? I have the allen head bolts underneath backed out slightly, and use the wing bolts to tighten things up.? Too much torque on those wing bolts, and I hear that noise, or I get stalls.? Too little torque on the wing bolts, and I get noticeable play when rocking the scope back and forth by hand in DEC.? It seems like I have to have virtually no torque on the wing bolts..... stop turning when you feel it stop turning when tightening.? Is that OK?
Thanks so much.
Dan
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Re: Losmandy G11 Gemini 1 Battery
Enol . ?Boost converter. ?There are a lot of Chinese knockoffs on fleabay which have been known to fail. ?Best you make your own. ?The Ti data sheets and app notes are sufficient to build one but do use star ground return? ive been thinking of doing one....just to try it. ?I had the opportunity to test one. ?It was excellent. I could hear the difference in the motors. ?
Cheers
--
Brendan
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Re: Losmandy G11 Gemini 1 Battery
Hi,
I'm interested, but shipping and taxes probably will cost more than the box itself. El you have a wiring and component diagram to made one??
Greetings, Enol.?
El lun., 10 may. 2021 3:44 a. m., Michael Herman < mherman346@...> escribi¨®: Dear Enol,
When properly balanced, and gears are not jammed, the G11 typically uses 0.20 to 0.25 amps in sidereal tracking.? If autoguiding, maybe 0.25 to 0.3 amps.? If fast slewing (brief times) expect 0.35 amps per motor.? This is using a 17V DC power supply, which gives 42% more torque than 12VDC only.??
I find it very useful to employ a power supply with voltage booster circuit, and with output ammeter and voltmeter.? The ammeter tells me if I have the axes balanced, and his much current my motors and Gemini are using.? The output voltmeter also tells if the input battery supply is drooping which will show up as output voltage drop.??
I make these supply units for Gemini-1 and -2.? Let me know if interested...!? Here are some photos...
All the best? Michael
Hi guys,
I have troubles with my actual battery, so I'm trying to get how amps this mount consume on a large night (7-8h).
I'm going to made a battery only for the mount. The rest of the components have other battery.
A 45Ah battery would work doing only 2 or 3 GoTo for autoguide aligment and night object without pass the 50% discharge, or I'll need a 60-70Ah battery?
The manual says you need at least 3Ah, I think for the GoTo commands to work. In tracking with guiding pulses how many consumes?
Greetings, Enol.
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Re: Reducing DEC Backlash with Titan 50
Aubrey, that is the great benefit of the hanging RA cord.? Hanging the cord and weight off to the East experimentally gives the lowest vibration (chatter) to the RA ring gear (worm wheel) as it is driven to the West by the worm.? ?? The torque on the RA axis is identical no matter what the RA position is or the Dec position.? It is the same torque regardless if meridian flip.
It is the only way to get the torque to be uniform.??
Give this a try....and see for yourself.? I was quite skeptical and didn't believe it til I tested this method.??
All the best, Michael
Thanks Michael, but its not clear how this works on both sides of the meridian. I am also operating remotely so everything has to work without dragging, snags etc. ? Aubrey ? Sent from for Windows 10 ? ? Aubrey, To maintain a constant torque on the RA axis, which is what you are seeking, you need to use a weighted cord wrapped around the RA axis.? Using an unbalanced counterweight rod the torque will vary as the RA axis rotates.?? You put that hanging weight on after your counterweights are balanced.? I am using 1 pound weight....I had tried 7 pounds earlier.? I'm not sure what is an optional weight to use.? My scope is a C14EdgeHD.? ? Here is a way I implemented on my Titan RA.? I hope the photos are clear enough.? The weight hangs to the East and always provides an Eastward torque.?? ? ? Thanks Michael for the comments. Fortunately at this time I only have one issue. That is when I am starting out in the lower east imaging, I have nice round stars with 10 min subs. But as the Counter weight Shaft and weights begin to pass the 45 degree angle, I begin to have more flattened stars. As it gets closer to the Meriden I get round stars again. I think I might have too much east bias on the weights. I am getting about 1+/- Arcseconds PEC when guiding. But I have to use the onboard PEC function. I have noticed that if you want good results with the G2 PEC you pretty much have to run it on each target as you begin each DSO. If you do it that way it will work on both sides of the Meriden. I use Maxim DL 6. for guiding and an SX Superstar. My Telescope is the AT 10¡± RC with CF Arms and shroud and 60 mm guide scope so I am caring about 50 LBS load with my heavy camera. ? Aubrey ? ? Sent from for Windows 10 ? ? Aubrey, It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.?? You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!?? Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing). Have fun,...get some nice images! ? Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Reducing DEC Backlash with Titan 50
Thanks Michael, but its not clear how this works on both sides of the meridian. I am also operating remotely so everything has to work without dragging, snags etc. ? Aubrey ? Sent from for Windows 10 ?
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From: Michael HermanSent: Saturday, May 8, 2021 10:14 PM To: [email protected]Subject: Re: [Losmandy_users_io] Reducing DEC Backlash with Titan 50 ? Aubrey, To maintain a constant torque on the RA axis, which is what you are seeking, you need to use a weighted cord wrapped around the RA axis.? Using an unbalanced counterweight rod the torque will vary as the RA axis rotates.?? You put that hanging weight on after your counterweights are balanced.? I am using 1 pound weight....I had tried 7 pounds earlier.? I'm not sure what is an optional weight to use.? My scope is a C14EdgeHD.? ? Here is a way I implemented on my Titan RA.? I hope the photos are clear enough.? The weight hangs to the East and always provides an Eastward torque.?? ? ? Thanks Michael for the comments. Fortunately at this time I only have one issue. That is when I am starting out in the lower east imaging, I have nice round stars with 10 min subs. But as the Counter weight Shaft and weights begin to pass the 45 degree angle, I begin to have more flattened stars. As it gets closer to the Meriden I get round stars again. I think I might have too much east bias on the weights. I am getting about 1+/- Arcseconds PEC when guiding. But I have to use the onboard PEC function. I have noticed that if you want good results with the G2 PEC you pretty much have to run it on each target as you begin each DSO. If you do it that way it will work on both sides of the Meriden. I use Maxim DL 6. for guiding and an SX Superstar. My Telescope is the AT 10¡± RC with CF Arms and shroud and 60 mm guide scope so I am caring about 50 LBS load with my heavy camera. ? Aubrey ? ? Sent from for Windows 10 ? ? Aubrey, It's the RA that this matters most on a Titan RA drive.? Variable friction causes the drive speed to slow then speed up...it's either periodic or non periodic error.? Either way you want it to be near zero friction.? That's what the bearings are for.? But the worm has the ring gear and no bearings at that interface...just friction.? So that needs the best lube and that's the question.?? You also want near zero backlash else you get autoguiding time lags and hysteresis that PHD2 does not like.? So that's the other end of the coin....no friction but no autoguiding!?? Between those two extremes is the optimization point.? Springs can help if they keep the surfaces in contact but not too tightly.? Lubes are essential to minimize friction. Aligning bearings to keep balls from pinching (the Titan has these bearings in a massive cylindrical sleeve...they can't go off axis...the OVision worm did this for the G11 and they used a Belleville R4 spring washer for the end bearing). Have fun,...get some nice images! ? Thank you. I have always just tightened my endcap down and did not notice it. I will check it out when it gets it¡¯s annual oil change. ? Thanks ? Aubrey ? Sent from for Windows 10 ? ? it¡¯s a spring washer rather than a spring, and is housed inside the worm block assembly.
Regards,
? -Paul
On Sat, May 8, 2021 at 12:47 PM, Aubrey Brickhouse wrote:
Can I ask a question on this subject. I have a fairly new Titan and I have never seen a spring in the assembly. I have relubed it several times but have never taken out the worm and so I can not say if mine has one or not. ? Thanks ? Aubrey Brickhouse ? Sent from for Windows 10 ? ? Dan, yes, indeed. I have a Titan50 and a G11 :)
The spring loaded adjustment I'm talking about is not for the whole worm block -- it's at the end of the worm block, on the opposite side of the gearbox. It pushes a spring-loaded bearing into the worm block, preventing it from moving horizontally, side-to-side. It may look like this, below, or have a single slot that you can use a screw-driver or a quarter to turn. If it's not pushed in far enough, the worm will float left to right:
Regards,
? ?-Paul
On Sat, May 8, 2021 at 10:27 AM, <dkfcpalfd@...> wrote: Paul:
Thanks for responding.? Do you have a Titan?? Losmandy has been telling me that they came out with spring-loaded worms for the G11, but not the Titan.? When I first heard about the spring-loaded worms for the G11, I initially was told that feature was in development for the Titan.? Then, several months later, that went away, and I have been hearing from them that spring-loaded worms may never happen for Titan.
Right now, I'm going to try adjusting up the TVC on the HC.... the Gemini-2 website says that is a built-in DEC backlash compensation adjustment that is available.
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Re: Losmandy G11 Gemini 1 Battery
Dear Enol,
When properly balanced, and gears are not jammed, the G11 typically uses 0.20 to 0.25 amps in sidereal tracking.? If autoguiding, maybe 0.25 to 0.3 amps.? If fast slewing (brief times) expect 0.35 amps per motor.? This is using a 17V DC power supply, which gives 42% more torque than 12VDC only.??
I find it very useful to employ a power supply with voltage booster circuit, and with output ammeter and voltmeter.? The ammeter tells me if I have the axes balanced, and his much current my motors and Gemini are using.? The output voltmeter also tells if the input battery supply is drooping which will show up as output voltage drop.??
I make these supply units for Gemini-1 and -2.? Let me know if interested...!? Here are some photos...
All the best? Michael
Hi guys,
I have troubles with my actual battery, so I'm trying to get how amps this mount consume on a large night (7-8h).
I'm going to made a battery only for the mount. The rest of the components have other battery.
A 45Ah battery would work doing only 2 or 3 GoTo for autoguide aligment and night object without pass the 50% discharge, or I'll need a 60-70Ah battery?
The manual says you need at least 3Ah, I think for the GoTo commands to work. In tracking with guiding pulses how many consumes?
Greetings, Enol.
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Losmandy G11 Gemini 1 Battery
Hi guys,
I have troubles with my actual battery, so I'm trying to get how amps this mount consume on a large night (7-8h).
I'm going to made a battery only for the mount. The rest of the components have other battery.
A 45Ah battery would work doing only 2 or 3 GoTo for autoguide aligment and night object without pass the 50% discharge, or I'll need a 60-70Ah battery?
The manual says you need at least 3Ah, I think for the GoTo commands to work. In tracking with guiding pulses how many consumes?
Greetings, Enol.
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Re: Full ceramic bearings on a G11
My advice to you having been down this road is, if you are happy with your current performance, leave it alone and get to imaging.? Don't let the hobby be about the mount.? I think the onus is on the reader to carefully interpret anyone's results before running out to buy a new part or modify the mount in some way (especially when the part is relatively costly like a ceramic bearing).? Plus you always risk not putting the pieces back together as optimally as you seem to have it now (or worse, causing damage like I did to one of my worms).
One can only assume Losmandy has investigated much of this, but they build to a price point and work within that to produce a cost-effective mount (e.g. the Ruland coupler in the original OPW is very costly).? And I'm sure their techniques and equipment have undoubtedly improved over the last 30 years.? So of course there are probably improvements that can be made, but like you say, it takes too much time which most of us have little of.? But if you want to put in the work, I'm sure many would be interested.
Keith
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Re: Full ceramic bearings on a G11
I posted 2 screen shots of two similar nights, one with the stock bearings and one with the ceramic bearing.
You are correct about the variables, and have been thinking about this. Should I go back to the stock bearings to get a sense of what has really changed? I did get very familiar with drive train, as I was dealing with it for several months when I first got the mount. I did not touch the stand off bolt that affects worm/ring gear mesh, and I use a straight edge to line up both blocks in order to keep the drive train as straight as possible. There are so many variables to take into account, that it seems almost impossible to do proper testing as hobbyist with limited time. I pretty much lost the winter months of imaging, and I really wanted to get back to it, so my metric was RMS improvement and how many frames I threw away per session(round stars). I did see improvement on both. I'm open to suggestions on testing and getting a clear answer.
Hugo.
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Both the inexpensive Meade DS and Celestron Nexstar GT mounts used Bellevue?washers on their worm assemblies. and wavy?washers elsewhere. Most step motors use one behind the bearing opposite the output shaft. I've got some surplus Tandon steppers made for IBM PC half height 5.25" floppy drives. When was that? In the '80s? Paid $2 a piece, so I don't worry about breaking them up for bearings, washers and fridge magnets.
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Bill P.
Michael Herman
Paul Kanevsky
Hugo_G