Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Hi Michael,
That's sounds good to me, My old AVX mount needed to be as tight as it could, to work properly. I've just gathered from earlier threads that you only need as to tighten the RA and DEC on a Losmandy G11 just enough.? HAPPY SKIES AND KEEP LOOKING
UP Deric
Sent from my Galaxy Tab A
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-------- Original message --------
From: Michael Herman <mherman346@...>
Date: 5/16/20 7:25 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
Hi Deric,
I believe that Brian is going to pursue the issue, and respond.??
Like I said, I can't really see any normal way this effect could occur...certainly not in a G11.? ?It was reported as a rare issue on GM8 mounts, but never similar problem with a G11.? The issue with GM8 was detectable, by measuring variations
in the tiny gap between the black anodized sections of the body.??
I will say you be aware of this: On all worm drive systems, the worm center axis is supposed to be at the exact center of the ring gear height.? On mounts like the Orion Atlas/Synta EQ6, there are thin plastic shims to adjust the height of the
internal ring gear.? But the Losmandy systems do not use any shims at all.? Instead the worm height is precisely set by the worm blocks and the worm R4ZZ bearings, and the worm dimensions.? It's therefore the ring gear height that I suspect...something is
pulling that up and down...it should not.
Another clue is that Mark Crossley's website , mentioned he had to add a thin shim under one worm block to get his G11 worm perfectly centered in the ring gear.? It's good to check that heights match correctly, if you find worm gear to ring gear issues.? It was easier (not exactly
easy!) to check in the original 2-block drive design.??
The worm height is set by it's blocks, but the height of the ring gear is set by the flat needle bearing, and it's facing flat race washers.? The races and flat bearings all have a variance in thickness, which might affect this height.? ? The
clutch disk is above that and should not affect the worm to ring centering.??
Let's let Brian work on an official answer to this rare issue of clutch knob force affecting the worm and ring gear.? It remains a puzzle to me.??
All the best,
Michael
Michael, interesting, I've been told that all you need to do is tighten the DEC and RA clutches just enough so they will not move. That over tightening can put stress on the worm and motors. So you dont see that this is a issue? "HAPPY SKIES
AND KEEP LOOKING UP"
Deric
Sent from my Galaxy Tab A
-------- Original message --------
Date: 5/16/20 3:11 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.? Note
that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull on
the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to tilt
the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
Best,
Michael
On Sat, May 16, 2020, 8:05 AM Henk Aling < haling@...> wrote:
Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear
pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure
itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and
documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms,
and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
|
Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Hi Deric,
I believe that Brian is going to pursue the issue, and respond.??
Like I said, I can't really see any normal way this effect could occur...certainly not in a G11.? ?It was reported as a rare issue on GM8 mounts, but never similar problem with a G11.? The issue with GM8 was detectable, by measuring variations in the tiny gap between the black anodized sections of the body.??
I will say you be aware of this: On all worm drive systems, the worm center axis is supposed to be at the exact center of the ring gear height.? On mounts like the Orion Atlas/Synta EQ6, there are thin plastic shims to adjust the height of the internal ring gear.? But the Losmandy systems do not use any shims at all.? Instead the worm height is precisely set by the worm blocks and the worm R4ZZ bearings, and the worm dimensions.? It's therefore the ring gear height that I suspect...something is pulling that up and down...it should not.
Another clue is that Mark Crossley's website , mentioned he had to add a thin shim under one worm block to get his G11 worm perfectly centered in the ring gear.? It's good to check that heights match correctly, if you find worm gear to ring gear issues.? It was easier (not exactly easy!) to check in the original 2-block drive design.??
The worm height is set by it's blocks, but the height of the ring gear is set by the flat needle bearing, and it's facing flat race washers.? The races and flat bearings all have a variance in thickness, which might affect this height.? ? The clutch disk is above that and should not affect the worm to ring centering.??
Let's let Brian work on an official answer to this rare issue of clutch knob force affecting the worm and ring gear.? It remains a puzzle to me.??
All the best, Michael
Michael, interesting, I've been told that all you need to do is tighten the DEC and RA clutches just enough so they will not move. That over tightening can put stress on the worm and motors. So you dont see that this is a issue? "HAPPY SKIES
AND KEEP LOOKING UP"
Deric
Sent from my Galaxy Tab A
-------- Original message --------
Date: 5/16/20 3:11 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.? Note
that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull on
the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to tilt
the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
Best,
Michael
On Sat, May 16, 2020, 8:05 AM Henk Aling < haling@...> wrote:
Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear
pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure
itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and
documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms,
and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
|
Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
My experience is that overtightening causes it all to jam up. Not great.
?
There is also a different feel of the worm spur gears when turned back and forth when trying to sort out backlash etc. Overtightening gives misleading ‘feel’.
?
Overtightening is not good. I do it up tight and then back but 1/3 to ? a turn – G11 Dec.
?
Please LISTEN to my attached video, does this sound right. Tight then turned back by a 1/3 of a turn. Even looser or tighter it sounds the same.
?
?
?
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Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Deric Caselli via groups.io
Sent: Sunday, 17 May 2020 7:46 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
?
Michael, interesting, I've been told that all you need to do is tighten the DEC and RA clutches just enough so they will not move. That over tightening can put stress on the worm and motors. So you dont see that this is a issue? "HAPPY
SKIES AND KEEP LOOKING UP"
Sent from my Galaxy Tab A
-------- Original message --------
Date: 5/16/20 3:11 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.?
Note that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull
on the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to
tilt the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
?
On Sat, May 16, 2020, 8:05 AM Henk Aling <haling@...> wrote:
Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a
consistentworm gear pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure
itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and
documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms,
and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient, you are hereby notified that any use, disclosure, copying or distribution of
this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Thanks Richard, for clarifying?that.? I thought that 1.4 kg was too small to pull that RA up off the clutch disk.??
I'm quite happy with the way my mount systems are working.? The moonlight and high humidity have stopped my imaging work for the moment.??
For the past week I've been visiting my family in the LA area.? I feel happy to have human touch for the moment, after 2 months of isolation at home.? But work and home maintenance require me to head home for awhile.? So I plan to drive home from Long Beach on Monday, to the San Jose area where my mounts and telescopes are.? I am dreading the drive back home to isolation again.??
I just ordered a cute little fiber input spectrometer, to hook up to that C14 system.? I should be able to get images, and stellar or nebula spectra from that.??
I also have a bunch of nice 300 and 500 sec RGB subs of M51 and some of M81 to process, debayer, and stack.? ?I'm waiting for planetary season to bring Jupiter, Saturn and Mars around again.? That's really what the C14HD was intended for.??
Meanwhile, trying to stay safe and healthy in this crisis.??
Stay well all!
Michael
Hi Michael
?
Bit of confusion, when RA is horizontal and I’m balancing the RA, I use portable electronic luggage scales,
at the end of the weight shaft to pull up and same to pull down, when the number is the same I call it balanced. Number is around 1.4 kgs.
?
With RA clutch “disengagement” system is in place, I do the same with luggage scales at the end of the horizontal weight shaft, the reading to move RA now is 0.2 kgs.
?
My dovetail weight is around 24 kgs.
?
Guide scope is SharpStar 61 EDPH with QHY5-III 178.
?
Nice – your G11 does look max’ed out !
?
Cheers Richard
?
From: [email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 7:25 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I'm curious: what is the kind of scope loaded on your G11T?
Can you estimate the total scope load weight on your dovetail?
I don't have a GT11 (yet) though I certainly have scopes heavy enough to warrant getting that size of mount.? I have several G11s, and a GM8 and a GM811.??
That your pull to get near zero clutch force is only about 1.4 kg ~ 3 lbs seems way too small.? I think the equation would be like?
Force = [Total weight of dovetail load + counterweights] x [cosine(elevation angle)]
Maybe your (very newish) system already has a wavy washer in the RA, and your lifter is just adding a little umph to that?? Brian could tell if the G11T has such a wavy washer in it's RA.? (The Titan RA clutch disk is about 6 inch diameter.)
So if you are at a pole your elevation angle would be 90 degrees, and there will be zero downward force on your RA clutch.? If you were at the equator, you would have 100% of the total weight on your RA clutch disk.? In between it would
go like the co sine function of the elevation angle.
I have about 130 lbs total scope + counterweight load on my maxed out G11.? ? That's a near 50 lb C-14HD, top dovetail and 80mm guide refractor, about 50 lbs of counterweights.? At my latitude of? 37°21', the cosine would be? 0.79.? So
I calculate needing 103 lbs pull to lift all the weight off the RA clutch disk.? I likely need some oak to lift that!!!??
At that point, I will give the ammeter test a try first.??
If I could make a software gadget... worth a try... I'd have something drive the Gemini to switch the RA drive using (a button for)? CW sidereal drive, or (a different button for) CCW sidereal drive, and a Pause/stop button.? ?Then, you
could pause, and shift the counterweights, and run back and forth CW va CCW directions to observe the drive current.? In that way, you would not need to change from Scope East vs Scope west positions.??
Someone recently asked about battery power needs to run a mount.? Some thoughts on that follow:
What current draw should you expect to use to run a G11 and Gemini, say?
(Note: Power =Amps x Volts, so the current should be smaller if the supplied volts is higher....if it were all due to motor power...but it isn't all motor power).
My amps used on a balanced G11 mount is around these values:
?Sidereal tracking with PHD2 ~2 sec pulse autoguiding:?
? ?0.17 amp at 17 volt DC power ~ 0.25 amp at 12 Volt DC power
Fast slew to distant target, or Park at CWD from a distant target:?
? ?0.6 amp per axis at 17 V ~ 0.9 amp at 12 Volt DC power.? So my max on my 17 volt system is about 1.4 amp.? On a 12 V system might be bear 2 amps max.? This fast slew time is brief...maybe 10 seconds max.
Dew heaters use up a lot of amps...a lot of a battery capacity will be drained quickly by the heater.? I estimate about 10 ohms per dew heater cable, so estimate about 1.2 Amps continuous per dew heater cable if powered at 12 volts.? If
you use a digital control, this is reduced by the duty cycle (on time/total time).? But if you are running off a field battery...watch out for killing your battery!? I did kill a 12 V gell pack battery by overdraining it on feeding a dew heater... can be a
costly lesson.??
So I'd run my mount and laptop off one battery, and use a separate battery for the dew heater(s).? If the dew heater battery is exhausted, you won't wipe out your camera and laptop.?
You might damage the dew heater battery if you drain it below some voltage level (like I'd guess 10 volts for a nominal 12 volt battery).? Below that you'd probably kill a wet cell.??
Thinking out loud: if you want a circuit to stop battery drain at some desired voltage, (say 10 volts) contact me and I'll make you up a battery drain protection circuit.??
All the best (a Starbucks Frappuccino at dinner is keeping me up most of the night.? At least it wasn't a COV19 attack... this virus panic is horrible...)
I'll mention:? I have a batch of Gemini-2 power booster units that I recently made up.? These have an output current digital luminescent meter (ammeter) for the output current.? The output voltage
is boosted to 17.1 volts internally by a polarity-protected circuit, from nominal 12 volts input.? That output voltage is also displayed by a digital luminescent display.? The polarity protection is to assure that anyone connecting to a battery input in the
dark has no worry about mistaking + for - pins going in... the box automatically switches it to be correct polarity going out to the Gemini unit.??
Here is a photo of a power booster unit driving the RA on that overloaded G11 mount. (And a daytime photo of the overloaded G11 as well). You see that the RA drive is only using about 0.16 amp...because
the RA is well balanced.? Most of that 0.16 amp is just running the Gemini (mine are Gemini-1, but you'd get about the same running a Gemini-2).? I get the same 0.16 amp running even a light scope and load.??
Anyone interested in trying one of these units...please contact me off line. I have a small batch of Gemini-2 units ready to go.? If you need a Gemini-1 unit, I will make them up too.? They all
come with the correct output cable to go to the specific Gemini units.? ?
?
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don’t have the desire to do anything on the RA.
?
Without the “pull” system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With “pull” system in place, I’m down to 0.2 kg. It’s almost neutral. Haven’t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope
cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.?
The wavy washer requires a slot machined in the drive clutch plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive
seems to have no trouble.? I can also use the current meter on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily
with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally – threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it’s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
This e-mail and any files attached are intended solely for the use of the addressee. They may contain privileged or confidential information. If you are not the intended recipient,
you are hereby notified that any use, disclosure, copying or distribution of this e-mail is strictly prohibited. If you receive this message in error, please notify the sender immediately and delete the message and any attachments from your system. Thank you.
|
Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Michael, interesting, I've been told that all you need to do is tighten the DEC and RA clutches just enough so they will not move. That over tightening can put stress on the worm and motors. So you dont see that this is a issue? "HAPPY SKIES
AND KEEP LOOKING UP"
Deric
Sent from my Galaxy Tab A
toggle quoted message
Show quoted text
-------- Original message --------
From: Michael Herman <mherman346@...>
Date: 5/16/20 3:11 PM (GMT-06:00)
Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob
Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.? Note
that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull on
the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to tilt
the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
Best,
Michael
On Sat, May 16, 2020, 8:05 AM Henk Aling < haling@...> wrote:
Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear
pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure
itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and
documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms,
and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
|
Hi Michael
?
Bit of confusion, when RA is horizontal and I’m balancing the RA, I use portable electronic luggage scales,
at the end of the weight shaft to pull up and same to pull down, when the number is the same I call it balanced. Number is around 1.4 kgs.
?
With RA clutch “disengagement” system is in place, I do the same with luggage scales at the end of the horizontal weight shaft, the reading to move RA now is 0.2 kgs.
?
My dovetail weight is around 24 kgs.
?
Guide scope is SharpStar 61 EDPH with QHY5-III 178.
?
Nice – your G11 does look max’ed out !
?
Cheers Richard
?
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From: [email protected] <[email protected]>
On Behalf Of Michael Herman via groups.io
Sent: Saturday, 16 May 2020 7:25 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I'm curious: what is the kind of scope loaded on your G11T?
Can you estimate the total scope load weight on your dovetail?
I don't have a GT11 (yet) though I certainly have scopes heavy enough to warrant getting that size of mount.? I have several G11s, and a GM8 and a GM811.??
That your pull to get near zero clutch force is only about 1.4 kg ~ 3 lbs seems way too small.? I think the equation would be like?
Force = [Total weight of dovetail load + counterweights] x [cosine(elevation angle)]
Maybe your (very newish) system already has a wavy washer in the RA, and your lifter is just adding a little umph to that?? Brian could tell if the G11T has such a wavy washer in it's RA.? (The Titan RA clutch disk is about 6 inch diameter.)
So if you are at a pole your elevation angle would be 90 degrees, and there will be zero downward force on your RA clutch.? If you were at the equator, you would have 100% of the total weight on your RA clutch disk.? In between it would
go like the co sine function of the elevation angle.
I have about 130 lbs total scope + counterweight load on my maxed out G11.? ? That's a near 50 lb C-14HD, top dovetail and 80mm guide refractor, about 50 lbs of counterweights.? At my latitude of? 37°21', the cosine would be? 0.79.? So
I calculate needing 103 lbs pull to lift all the weight off the RA clutch disk.? I likely need some oak to lift that!!!??
At that point, I will give the ammeter test a try first.??
If I could make a software gadget... worth a try... I'd have something drive the Gemini to switch the RA drive using (a button for)? CW sidereal drive, or (a different button for) CCW sidereal drive, and a Pause/stop button.? ?Then, you
could pause, and shift the counterweights, and run back and forth CW va CCW directions to observe the drive current.? In that way, you would not need to change from Scope East vs Scope west positions.??
Someone recently asked about battery power needs to run a mount.? Some thoughts on that follow:
What current draw should you expect to use to run a G11 and Gemini, say?
(Note: Power =Amps x Volts, so the current should be smaller if the supplied volts is higher....if it were all due to motor power...but it isn't all motor power).
My amps used on a balanced G11 mount is around these values:
?Sidereal tracking with PHD2 ~2 sec pulse autoguiding:?
? ?0.17 amp at 17 volt DC power ~ 0.25 amp at 12 Volt DC power
Fast slew to distant target, or Park at CWD from a distant target:?
? ?0.6 amp per axis at 17 V ~ 0.9 amp at 12 Volt DC power.? So my max on my 17 volt system is about 1.4 amp.? On a 12 V system might be bear 2 amps max.? This fast slew time is brief...maybe 10 seconds max.
Dew heaters use up a lot of amps...a lot of a battery capacity will be drained quickly by the heater.? I estimate about 10 ohms per dew heater cable, so estimate about 1.2 Amps continuous per dew heater cable if powered at 12 volts.? If
you use a digital control, this is reduced by the duty cycle (on time/total time).? But if you are running off a field battery...watch out for killing your battery!? I did kill a 12 V gell pack battery by overdraining it on feeding a dew heater... can be a
costly lesson.??
So I'd run my mount and laptop off one battery, and use a separate battery for the dew heater(s).? If the dew heater battery is exhausted, you won't wipe out your camera and laptop.?
You might damage the dew heater battery if you drain it below some voltage level (like I'd guess 10 volts for a nominal 12 volt battery).? Below that you'd probably kill a wet cell.??
Thinking out loud: if you want a circuit to stop battery drain at some desired voltage, (say 10 volts) contact me and I'll make you up a battery drain protection circuit.??
All the best (a Starbucks Frappuccino at dinner is keeping me up most of the night.? At least it wasn't a COV19 attack... this virus panic is horrible...)
I'll mention:? I have a batch of Gemini-2 power booster units that I recently made up.? These have an output current digital luminescent meter (ammeter) for the output current.? The output voltage
is boosted to 17.1 volts internally by a polarity-protected circuit, from nominal 12 volts input.? That output voltage is also displayed by a digital luminescent display.? The polarity protection is to assure that anyone connecting to a battery input in the
dark has no worry about mistaking + for - pins going in... the box automatically switches it to be correct polarity going out to the Gemini unit.??
Here is a photo of a power booster unit driving the RA on that overloaded G11 mount. (And a daytime photo of the overloaded G11 as well). You see that the RA drive is only using about 0.16 amp...because
the RA is well balanced.? Most of that 0.16 amp is just running the Gemini (mine are Gemini-1, but you'd get about the same running a Gemini-2).? I get the same 0.16 amp running even a light scope and load.??
Anyone interested in trying one of these units...please contact me off line. I have a small batch of Gemini-2 units ready to go.? If you need a Gemini-1 unit, I will make them up too.? They all
come with the correct output cable to go to the specific Gemini units.? ?
?
Not sure what my RA washer configuration is, mount is only 1 ? years old. Dec I pulled apart heaps and don’t have the desire to do anything on the RA.
?
Without the “pull” system, due to higher system load (which is why I bought the G11GT), I measure about 1.4 kgs at the end of the weight shaft to pull up and same to pull down.
?
With “pull” system in place, I’m down to 0.2 kg. It’s almost neutral. Haven’t tried to get to neutral, will try to see what I can get to next time I setup.
?
Yes, Dec much easier to do, including a little push from the counterweight end to completely free it all.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 2:37 PM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
The extra photos explain your design...the bolts in front push on metal plates, and lift the upper front wood piece, which is attached to the wire holding the front polar scope
cover.? Very clever!
The takeaway for me was that, using this method, you did find the RA axis much easier to rotate for perfect balance.? You got the same benefit as the "wavy washer" new design.?
The wavy washer requires a slot machined in the drive clutch plate area which my earlier mount designs don't have.? So...you provided some ideas to try.? ?
As for me, to date, I have used a "push" in both rotation directions on my RA axis to get a sense of the RA counterweight balance.? As long as that is pretty close, my RA drive
seems to have no trouble.? I can also use the current meter on my Gemini power supply to measure the sidereal drive current with the scope on the East, vs West, side of the mount.??
For DEC, it is far easier...just put the counterweight rod horizontal, and loosen the DEC clutch knob. Then there is zero weight on the DEC clutch and that axis swings around easily
with no friction.? That is simple to rebalance.??
Thanks again Richard for sharing your wood lift design.? Something new to try out...!? ?
?
Hi Michael
?
I had the idea and then just made it up quickly using some left over wood from a wine rack, 150 ib tracer wire and large swivel from fishing tackle shop, two large screws, a couple
of washers and a pin of some sort (or use an allen key).
?
If designed professionally – threaded tube could screw into the RA cover thread and then have the frame and finally something like the Dec clutch tightening knob that threads onto
the same threaded tube.
?
Hope the pictures make sense.
?
Regards Richard
?
?
From:
[email protected] <[email protected]>
On Behalf Of Michael Herman via
Sent: Saturday, 16 May 2020 10:15 AM
To: [email protected]
Subject: Re: [Losmandy_users_io] Balancing RA
?
Hi Richard,
I watched your video...now that you mention your "gear puller" I see your wooden rectangular enclosure briefly appears in the video.
I see that the wooden rack pushes down on the RA body mounting, and the front wooden part is attached to the RA front polar scope cover.? There are what appear to be wires pulling
up on the RA cover knob, and the wires lift the RA weight off the RA clutch, so it will rotate more easily.??
How do you adjust the wires to pull up?? I see some bolts in front.? Can you sketch or describe how that mechanism?works?
Anyway, that's quite a clever wood lifter idea.? Thanks for sharing that?with the group.
?
Hi Rick
?
I have a G11GT so it’s the Titan RA. I use electronic luggage scales and at the end of the weight shaft pull up then pull down, adjust until the numbers are the same.
?
The heavier your load and higher the altitude the worse it gets.
?
Lately I build like a gear puller to help with the balancing the RA. Pulls the weight off the clutch plate so balancing much more accurate. See video attached.
?
?
?
From:
[email protected] <[email protected]>
On Behalf Of rboudah via
Sent: Saturday, 16 May 2020 12:07 AM
To: [email protected]
Subject: [Losmandy_users_io] Balancing RA
?
Hi just received new G11G and was trying to balance the RA axis and at my latitude of 45 degrees and there was way to much friction to balance the mount. This mount definitely needs
the wavy washer. To get around this I used 2 methods to find balance.
1. Set the altitude adjustment to 0 so that all loads are on the bearings and none on the friction plate. This works perfectly.
2. I have an amp meter on my battery box so I set the RA axis to horizontal and slewed in one direction and then the other waiting for the current to steady . I adjusted the weight so that the current was the same. This I could do with the altitude at 45 degrees.
Both were very close to each other.
Rick
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Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
The lowest clutch pressure without slippage is the best setting but this only works well if the mount is reasonably well balanced. There is noting in the mechanical design that would cause more or less pressure to change the tracking pe se, the axles are rolling on bearings and the thrust bearings are carrying the thrust load of the clutch. If you apply enough force there will be additional crag that can affect PE but why apply more than enough force than necessary to lock the clutches?? ??
--
Chip Louie - Chief Daydreamer Imagination Hardware
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Re: G11G First Night - Not So Good
Rick at what point in this guidelog did you have PEC on?
did you do it at the start and maybe disable/reenable?
Also pls check your TVC value = 0 on hand controller?
Brian
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Re: G11G First Night - Not So Good
>>>
For PEC I used the functions in the ASCOM driver.
Got it - yeah i thought you might have
Built-in PEC is really only for visual. I don't recommend it for imaging
Here is the log.
For PEC I used the functions in the ASCOM driver.
As for PEMPro I was hoping to avoid spending another $150 , but mostly having to learn yet 1 more piece of software.
Rick
-- Brian?
Brian Valente portfolio
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Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Michael
I seem to remember a post at least a year ago that detailed bearings that were not pressed in co-linear with the flat surface so that tightening the clutch plate put uneven pressure on the whole assembly. In fact, the post claimed if you put enough pressure, i.e., torqued the crap out of it, the flat surface may warp. To check co-linearity takes a dial caliper and checking bearing depth from four spots 90 degrees apart from the flat surface. This post said that once the bearings were pressed in evenly, the ring to worm contact surface also became even.
Chuck
-----Original Message----- From: Michael Herman <mherman346@...> To: Losmandy_users < [email protected]> Sent: Sat, May 16, 2020 01:11 PM Subject: Re: [Losmandy_users_io] G11 Dec Axis, How Tight to Do Up Clutch Knob Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.? Note that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull on the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to tilt the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
Best, Michael
On Sat, May 16, 2020, 8:05 AM Henk Aling < haling@...> wrote: Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms, and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
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Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Dear fellows,
I have read many similar reports over the past few years, about worm to ring gear tightness being affected by clutch knob tightness.
Strictly speaking, from the design itself, if all the parts are solid and all the shafts are perpendicular, there should be no effect of the clutch knob force.? At least, I should say, I can't see a part that should be affected.
Why: let's take the DEC axis (RA is similar).? Starting from the body section, there is a flat metal section above the 1.25 inch OD cylindrical needle bearings, holding the flat needle bearing, and it's flat upper and lower race washers.? Note that (on my systems) those 2 washers are not identical, so the assembly order matters: the lower flat washer should be the thin one, then the flat needle bearing, then the thicker flat race washer.??
The top of the ring gear is the bottom surface below the clutch pad.? The flat ring gear below the clutch pad is held firmly in place by the DEC body held by the RA section below it.? The ring gear aka worm wheel cannot shift from the pull on the flat clutch surface above it.? So the worm gear, also attached to the DEC body, should never see any distortion from the clutch knob pulling down on the upper clutch plate.
But many people see something happening... what could be causing it?
Let me toss out an idea...perhaps the assembly of the upper flat needle bearing races is done wrong:
If the lower race washer were the thicker one (by mistake in assembly), the upper race washer may be too thin to stay centered on the 1.25 inch axis.? If not centered, perhaps in that case pulling down on the clutch shaft could start to tilt the ring gear with respect to the worm gear. Then the effects you notice...the clutch knob force affecting the worm gear might occur.
Anyway, that's the only easy explanation I can suggest...
Best, Michael
On Sat, May 16, 2020, 8:05 AM Henk Aling < haling@...> wrote: Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms, and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
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Re: G11G First Night - Not So Good
Here is the log.
For PEC I used the functions in the ASCOM driver.
As for PEMPro I was hoping to avoid spending another $150 , but mostly having to learn yet 1 more piece of software.
Rick
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Re: G11G First Night - Not So Good
Hi Rick
if you'd like some constructive feedback, i'd really need to see the actual guidelogs themselves
it should show a good calibration, a guiding assistant run, and at least 15 mins of uninterrupted guiding
regarding PEC, i'm not sure how you went about it? For me, it usually takes quite a while using PEMPro to gather the correct data with enough worm cycles, select the best fit algorithm, and rerun the results to see if the curve needs to be inverted.?
If you're not doing something roughly along these lines with PEMPro, i'm not surprised PEC doesn't show any benefit, and would probably make it worse
Here is the same data with the PHD2 Viewer.
I found there is a lot of drag on the spur gears from the motors and you can not feel the point at which the worm releases and yet still no backlash. The video shows what to look for and does not have motors attached.
My initial results looks OK so I decided to give PEC a try but was getting no improvement. Then things started to get much worse as shown in PHD2 Final.jpg. As you can see the DEC is fine but RA got about 5 times worse with the peak at 1/2 worm frequency.? These were looking at 2 different areas of the sky the initial file was of M13 which was in the eastern sky the final file was the trifid nebula in the southern sky. Could there be a worm gear issue.
All of the PHD2 settings were similar on these 2 attachments. I tried other control schemes but none worked any better.
-- Brian?
Brian Valente portfolio
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Re: Star GPS NX / G-11 Gemini
If anyone is interested in a working Star Gps system, I have one for sale. I am also selling it with the later adapter to use it with the gemini 2 if you ever want to upgrade!
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Re: G11G First Night - Not So Good
Here is the same data with the PHD2 Viewer.
I found there is a lot of drag on the spur gears from the motors and you can not feel the point at which the worm releases and yet still no backlash. The video shows what to look for and does not have motors attached.
My initial results looks OK so I decided to give PEC a try but was getting no improvement. Then things started to get much worse as shown in PHD2 Final.jpg. As you can see the DEC is fine but RA got about 5 times worse with the peak at 1/2 worm frequency.? These were looking at 2 different areas of the sky the initial file was of M13 which was in the eastern sky the final file was the trifid nebula in the southern sky. Could there be a worm gear issue.
All of the PHD2 settings were similar on these 2 attachments. I tried other control schemes but none worked any better.
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Re: G11G First Night - Not So Good
Hi Rick
I'm a little confused about what you have here - are you measuring periodic error correction while guiding?
if you are not doing PE correction, then the PEMPro log viewer is not a good way to view your results. use the PHD Log viewer instead.?
i don't know how you are going about this, but there's a number of things you mention that are not correct
- you do not need to remove the motors to adjust the worms, and adjusting the worms is probably not necessary for what you are trying to do right now anyways
(the following only applies if you are doing PE correction)
- PEC correction is only for RA, it has nothing to do with DEC
- your initial PEMPro PE run (uncorrected) looks on the good side of pretty typical:?+/- 4" (the mount is spec'd at?+/-5")
- the correction run (second run?) looks bad. What fitting algorithm did you use?
Again, if I misunderstood what you are doing, my apologies, and use PHD log viewer instead
Here are a couple of shots using PEMPro Viewer to show last nights initial run with a new G11G. The first one was good in DEC and not bad in RA. Then tings got bad with the RA by the end of the night. Huge deviations at exactly 1/2 worm period. Anyone else seen this before.
This morning I redid all of worm adjustments as per the video on YouTube. Discovered you must remove the motors so you can feel the drag when adjusting the last screw that pulls the worm back from the gear.
Also if Losmandy is reading these please mill some slots down the sides of the the motor heat sinks to get better access to the mounting screws.
Guiding is PHD2 with a ZWO ASI290mm on their 60mm guide scope. This is solidly mounted on top of a C8 and has usually produced? .9 to 1.5rms with a CGEM mount.
Rick
-- Brian?
Brian Valente portfolio
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Re: G11G First Night - Not So Good
Get you a set of ball end hex wrenches. That will make getting the screw out much easier.
Greg Morris
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G11G First Night - Not So Good
Here are a couple of shots using PEMPro Viewer to show last nights initial run with a new G11G. The first one was good in DEC and not bad in RA. Then things got bad with the RA by the end of the night. Huge deviations at exactly 1/2 worm period. Anyone else seen this before. I tried learning and applying PEC a few times but that did not help. Each PEC learning curve looked completely different.
This morning I redid all of worm adjustments as per the video on YouTube. Discovered you must remove the motors so you can feel the drag when adjusting the last screw that pulls the worm back from the gear.
Also if Losmandy is reading these please mill some slots down the sides of the the motor heat sinks to get better access to the mounting screws.
Guiding is PHD2 with a ZWO ASI290mm on their 60mm guide scope. This is solidly mounted on top of a C8 and has usually produced? .9 to 1.5rms with a CGEM mount.
Rick
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Re: G11 Dec Axis, How Tight to Do Up Clutch Knob
Thanks for bringing this up.? The worm gear pressure depends on the tightening of the worm gear (assuming no spring loaded ones) but also on the tightening of the clutch knob.? I finally figured out that the only way for me to achieve a consistentworm gear pressure is to shim the outer block with some foil against the frame, then pressing inwards and axially while tightening it.? That was the only way in which I could get my EQStar motors to make a full turn.?
I was happy, then I found to my surprise that the pressure depends equally on the tightening of the clutch knob.? I don't think this is right but it is what it is.? My plan is to mark the clutch knob position with a piece of tape on both sides.? The pressure itself does not matter much IMHO, what matters is that you achieve the same pressure each time.? So if you can mark it you should be good.? Find that point then adjust the worm gear using shims.?
At least, that works for me.? IMHO regulating the worm gear is a huge issue.? I thought it was good for me to upgrade from my AVX to a Losmandy, wanting to buy American.? It almost got me out of the hobby, unfortunately.? If someone would have researched and documented this, that would have helped greatly.? Just trying to do this manually as is still shown on the video, simply does not work with the Celestron or EQStar motors, and will lead to much frustration.? I can't tell you how many times I adjusted the worms, and having goto motors (not the ones with the Celestron kit) is virtually necessary to test it.
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Re: Star GPS NX / G-11 Gemini
Hi John, I’ve never used a Star GPS, but if a weak Gemini battery would cause a “GPS Timed Out” message, it may be good to replace the battery and reset all the parameters. I used to replace them every six months, which eliminated a lot of sudden, late night issues. HTH.
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My Star GPS has been working perfectly with my Gemini 1 for a long time. I always power up the GPS and allow it time to get a fix before starting the Gemini. Once the Gemini starts it would always say "SRAM/RTC Updated" but last night it said "GPS Timed out" and I tried 3 times but the same?? Nothing has changed as far as I know and the internal battery in the Gemini was changed on March 19 2019. Any suggestions?
?Thanks
John
--
Dean
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Michael Herman
Chip Louie
Ross Elkins
Greg