Re: Case for G1 Hand Controller
Hi David,
Sorry, I have no idea.
But I can bob this to the top for you.
Hopefully one of the other chaps have an idea.
But, Merry Christmas!
--
SonnyE
(I suggest viewed in full screen)
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Re: *Exact* method for minimizing backlash with spring loaded worm
On Sun, Dec 20, 2020 at 07:15 PM, Brian Valente wrote:
That is a bit of art to it is to find that point
And it is a learned art. Like muscle memory, or the right Thumb Tight. The parts are all as precision machined as is possible. But everything has to be broken in. And the human touch allows for the finest of adjustment. Once you learn it. And why it's a Learned Art. ;^) That's why when I see where somebody takes their mount apart, then complains it doesn't work right, I will usually just walk away from the post. I actually followed a thread where some new owner was whining and after several posts, the guy admitted he had not actually used his new mount due to the weather. He'd been occupying his time taking his brand new mount apart to look at the pieces, then reassembling them. :^0 I wouldn't give two hoots in hell for that mount. There is no way to tell what that owner may have done. But for sure, all possible human touch adjustment was gone. Gone to incessant tinkering of a bored mind. You can lead a horse to water, but you can't make him think. Martha sez, "If it works, don't "Fix" it. Mine is still breaking in. And it gets better and better. I marvel at what long exposure imaging I can do. YMMV ? -- SonnyE (I suggest viewed in full screen)
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Re: Spring Loaded Worm - Is this normal?
Hi Al
>>>I'm wondering exactly what the role is of the two screws that pull the blocks perpendicular to the ring gear.??
can you snap a picture of exactly which screws you are referring to? I just want to be clear on this
>>>
Brian I'd be curious whether this matches your experience and any recommendations.
When i'm tracking, no motors really make any noise for me. Are you referring to slewing or something else?
HI folks, I've been reading this thread with interest having performed the same operation lately myself.
I'm wondering exactly what the role is of the two screws that pull the blocks perpendicular to the ring gear.? When should they be adjusted, and how tight should they be?? It seems from my efforts that they need to be reasonably tight to prevent backlash, but I do worry about reducing the mobility of the SLW.
Finally, I don't know if this might be helpful for others, but I find that my system makes three different tones (I have a recent build 2020).? One is a fairly atonal gear noise when things aren't tight enough, another is a medium-high pitched humming tone when things are just right (to my perception anyway) and a third is a warbling high pitched tone when things get too tight.? Unfortunately I haven't been able to create the middle option consistently across the rotation of RA so I end up with a bit of #1 and #2.? Brian I'd be curious whether this matches your experience and any recommendations.
Thanks
-Al
-- Brian?
Brian Valente portfolio
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Re: First time using PHD2
Hi Robert
i don't think you necessarily need smaller pixels, but posting your guidelogs would help clarify that
Within the last few years PHD has done an excellent job in sub-pixel accuracy, down to 1/10th of a pixel.
I guide with a lodestar all the time (8.2um pixels) and can get as low as 0.6" guiding
Thanks Brian - yes I think it is all working as it should but I need to change the guide camera to get a lower number of arc seconds per pixel - with the camera/scope combination I used it was at around 8 arc seconds per pixel.
-- Brian?
Brian Valente portfolio
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Re: Mounting a Guide Scope to a G11 Mount
Hi
Thanks to everyone for your recommendations and advice on selecting and mounting a Guidescope on my G11.
Regards
Terry
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Re: Spring Loaded Worm - Is this normal?
HI folks, I've been reading this thread with interest having performed the same operation lately myself.
I'm wondering exactly what the role is of the two screws that pull the blocks perpendicular to the ring gear. ?When should they be adjusted, and how tight should they be? ?It seems from my efforts that they need to be reasonably tight to prevent backlash, but I do worry about reducing the mobility of the SLW.
Finally, I don't know if this might be helpful for others, but I find that my system makes three different tones (I have a recent build 2020). ?One is a fairly atonal gear noise when things aren't tight enough, another is a medium-high pitched humming tone when things are just right (to my perception anyway) and a third is a warbling high pitched tone when things get too tight. ?Unfortunately I haven't been able to create the middle option consistently across the rotation of RA so I end up with a bit of #1 and #2. ?Brian I'd be curious whether this matches your experience and any recommendations.
Thanks
-Al
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Re: First time using PHD2
Thanks Brian - yes I think it is all working as it should but I need to change the guide camera to get a lower number of arc seconds per pixel - with the camera/scope combination I used it was at around 8 arc seconds per pixel.
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Re: First time using PHD2
Thanks John - that document looks really useful
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Re: First time using PHD2
Hi Ian
You would need to upload your guidelog to see what is going on
I am happy to look at it, but you may also be better off posting to the PHD forums
from what little i can see in your screen capture, it's possible things are okay except the RA clearly shows some excursions
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Re: First time using PHD2
Hi Ian,
Please see attached document about analyzing your PHD2 guiding. From a glance at your guide output, the regular sine wave pattern in RA suggests regular periodic error your mount is trying to keep up with. Sounds like you need some worm block fine tuning or perhaps a new worm. That is a whole loaded topic and some of the adjustments can be found within the Losmandy YouTube videos. That might be a good place to start. With my Gemini 2, I would run PEMPro and upload the correction curve to the mount, but I don't know anything about the older drive systems.?
For guide cams, folks were using a Starlight Xpress Lodestar for quite awhile, but now many seem to be favoring the ZWO ASI120 or 290's, which are better cams for a lower price. The 290 is working OK for me.
I'm sure you'll be getting better and more detailed feedback here as Monday rolls around.
Regards,
John
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Re: *Exact* method for minimizing backlash with spring loaded worm
On 12/20/2020 10:06 PM, Michael Herman wrote: Hi Paul,
That "out of round"observation sounds like something could be damaged or mis-assembled., or just a bad component.? There is virtually no way a new component would be "out of round", Because of the relatively high spring tension and critical adjustment of the stop screw, VERY small worm eccentricities will have a large effect on the drag. I don't think anything is bent or damaged.... or even out of tolerance. It just isn't perfect and I never expected it to be. The mount is only a couple months old and was like this as received.... I could always hear the motor load changing up and down during a slew on both axes as the worm revolved. Because the spring tension is as high as it is but mitigated by the stop screw, the drag can increase and decrease a lot as the worm rotates unless the worm is absolutely perfect. c) off center axis ring gear? The eccentricity in my case is at the worm fundamental (about 750mS at slew speed), so the ring gear would not be responsible. Anyway, that's the way you diagnose a bad part...by swapping RA and DEC components, and keeping track of the results. In my case, the two worms seem to behave about the same so I'm in no hurry to swap them. And to be clear, they are not terrible. I have about 7-10 arcseconds of peak RA periodic error with PEC and tracking disabled. I'm not complaining about that at all.... I was just curious how the factory recommends dealing with worm eccentricities when adjusting the stop screw for best results. My guess would be to adjust on the loose side for RA (where backlash is not an issue except for pointing) and tighter for DEC? Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: *Exact* method for minimizing backlash with spring loaded worm
you're right - things that are best done "by touch" are tough to describe in writing
I can just relate my experience, which I think mirrors yours
i did a bunch of these with Scott and I initially adjusted it along the lines of what you described - just the smallest amount of tension
But Scott was pretty specific that it needed to go just a little further. I was struck that the factory adjustment seemed to move quite frreely, but it was only just at that point where it moved freely. That is a bit of art to it is to find that point
Brian-
This is such a "feel" based thing that I think it's difficult to convey in an online discussion. Like adjusting valves in an engine or a bicycle hub correctly...
Put it this way, tightening of the bolt to back the worm off just slightly too far, (by my measure), makes the whole system feel "sloppy" at the gear box gears. The point I try to get to seems to eliminate that without causing enough drag to be discernible in the sound/function of the motor.
?
Does that seem about right, or should it be at the "sloppy" stage?
-- Brian?
Brian Valente portfolio
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Re: *Exact* method for minimizing backlash with spring loaded worm
Hi Paul,
That "out of round" observation sounds like something could be damaged or mis-assembled. , or just a bad component.? There is virtually no way a new component would be "out of round", but... it?could be one of three low probability causes. ? My suspicions are:
a) a bad worm bearing. These are R4 size (R4ZZ or others that size).? These are used in roller skates and rollerblades, etc. so a huge market volume.? you can buy super quality listed as "ABEC-7" for about $13 each.? I recommend you replace the ones in your RA and if the DEC is the problem, replace those too.? These are small bearings, and not all that strong.? Still,?I've never heard of?them getting broken except when I try to remove a stuck one.? However the center rotating part can become?loose if the bearings are not strongly held in place by?the bearing blocks, or if a bearing block is off kilter.??See the possible bearing block trouble that Mark Crossley identified in his website .?
b) damaged Worm axle (that is 1/4 inch diameter). The modern worm is made of brass, and the older version was made of?stainless steel.? I suppose it might be possible to bend the worm shaft if the mount was severely dropped.?But I've never seen a bent worm on any of my mounts.? Brass is softer than stainless steel, but still very strong stuff.?? Solution: switch the RA and DEC worms.? Does the problem move with the worm (if so, it is definitely a damaged worm), or does it stay with the axis (bearing or ring gear problem)?
c) off center axis ring gear?? The ring gear is not really precisely centered but instead is mounted on top of the upper flat "thrust bearing" that is a flat needle bearing.? The center of that bearing rides on a brass cylinder up the middle of the axis.?The assembly order of the parts matters: the upper flat thrust bearing has a thin "race washer" under the bearing, and a thicker race on top of the bearing.? The
thinner?race must be the lower?one, else the ring gear won't be able to touch and be centered by the low brass cylinder.? If the upper thrust bearing is not centered right, then I think?the ring gear could rotate?off center.? That assembly must be correct.? It wouldn't go wrong by itself.?
Anyway, that's the way you diagnose a bad part...by swapping RA and DEC components, and keeping track of the results.??
Best of luck with this effort,
Michael
On Sun, Dec 20, 2020, 1:55 PM Paul Goelz < pgoelz@...> wrote: On 12/20/2020 4:24 PM, Brian Valente wrote:
> Hi Anthony,
>
> I spent quite a bit of time with Scott on this and you actually want no
> friction in there just at the point where there is no friction. It¡¯s
> hard to convey that in a video I know but that is my best advice to you.
> I did about two dozen of these practicing.
Out of curiosity, how do you deal with imperfect worms?? Both of mine
are slightly out of round such that the friction changes as the worm
turns.? Currently I split the difference but is his recommendation to
adjust so that there is no added resistance at the TIGHTEST portion of
the worm rotation?
Paul
--
Paul Goelz
Rochester Hills, MI? USA
pgoelz@...
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Re: *Exact* method for minimizing backlash with spring loaded worm
Paul-
I have had similar concerns about the very slight eccentricity of the main gear. As you slew around the circumference of it, if the worm is too tight, you can hear the motor working harder.
This is in part how I arrived at my method.
-A
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Re: *Exact* method for minimizing backlash with spring loaded worm
Brian-
This is such a "feel" based thing that I think it's difficult to convey in an online discussion. Like adjusting valves in an engine or a bicycle hub correctly...
Put it this way, tightening of the bolt to back the worm off just slightly too far, (by my measure), makes the whole system feel "sloppy" at the gear box gears. The point I try to get to seems to eliminate that without causing enough drag to be discernible in the sound/function of the motor.
?
Does that seem about right, or should it be at the "sloppy" stage?
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Re: What to ask/check when buying a used G11?
Stephen - it sounds like you have it nailed.?
We should probably be asking *you* for advice :)
On Sun, Dec 20, 2020 at 3:58 PM Stephen Leander < sleander1@...> wrote: [Edited Message Follows]
Well, of course the weather is not cooperating, cloudy and windy here today, so doubt I'll get it out tonight.? I spent some time familarizing myself with the mount, get my scope on a Losmandy plate and balanced (not much to it), pulled the RA and DEC shafts to clean the clutches and check the grease.? RA clutch pad is in pretty poor shape, DEC is a little better, will order replacements from Losmandy tomorrow and might clean and re-grease when I replace the pads with SuperLube, but the existing grease looked and felt fine.? Got my computer and PHD talking to the mount over Ethernet, firmware was already up-to-date, just need the weather to get better.
I also ordered up some shorter USB cables and a hub that I'll mount on the plate to clean up the cables a little bit, no really good way to run cables on this mount. Oh, also had to order up a new battery for the mainboard, using a CR2032 (same voltage, less mAH capacity) I had with a penny as a spacer to make it work for now.? I'll run it thru the baseline with PHD2 as soon as I can!
Thanks!
Steve
-- Brian?
Brian Valente portfolio
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Re: What to ask/check when buying a used G11?
Well, the clouds cleared and the wind died down, so I started to stage the equipment outside around 5pm, and that pissed off Mother Nature apparently - she turned the wind back on. Put everything back inside...? Life here in the Rockies!
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Case for G1 Hand Controller
I have a G1 in with a damaged HC case.
Does anyone know what brand and model that case is?
Thanks
David
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Re: *Exact* method for minimizing backlash with spring loaded worm
>>>
Currently I split the difference but is his recommendation to adjust so that there is no added resistance at the TIGHTEST portion of the worm rotation?
it's a two-part answer first, yes you split the difference. It's the same advice as with a non-spring loaded worm (SLW). it's worth going through and finding the tight spot and ensuring it's not too tight. With a SLW it will be less sticks-or-not, and more gets-tighter
second, when you get back to the looser part of the worm, you may find it's fine. if you think it's too loose, you can tighten the spring a little more and then back it off using the second screw. this will give the worm a bit more tension.?
You want to watch for stiction so if you start to see that, you may need to back off the tension a bit?
On Sun, Dec 20, 2020 at 1:55 PM Paul Goelz < pgoelz@...> wrote: On 12/20/2020 4:24 PM, Brian Valente wrote:
> Hi Anthony,
>
> I spent quite a bit of time with Scott on this and you actually want no
> friction in there just at the point where there is no friction. It¡¯s
> hard to convey that in a video I know but that is my best advice to you.
> I did about two dozen of these practicing.
Out of curiosity, how do you deal with imperfect worms?? Both of mine
are slightly out of round such that the friction changes as the worm
turns.? Currently I split the difference but is his recommendation to
adjust so that there is no added resistance at the TIGHTEST portion of
the worm rotation?
Paul
--
Paul Goelz
Rochester Hills, MI? USA
pgoelz@...
-- Brian?
Brian Valente portfolio
|
Re: What to ask/check when buying a used G11?
Well, of course the weather is not cooperating, cloudy and windy here today, so doubt I'll get it out tonight.? I spent some time familarizing myself with the mount, get my scope on a Losmandy plate and balanced (not much to it), pulled the RA and DEC shafts to clean the clutches and check the grease.? RA clutch pad is in pretty poor shape, DEC is a little better, will order replacements from Losmandy tomorrow and might clean and re-grease when I replace the pads with SuperLube, but the existing grease looked and felt fine.? Got my computer and PHD talking to the mount over Ethernet, firmware was already up-to-date, just need the weather to get better.
I also ordered up some shorter USB cables and a hub that I'll mount on the plate to clean up the cables a little bit, no really good way to run cables on this mount. Oh, also had to order up a new battery for the mainboard, using a CR2032 (same voltage, less mAH capacity) I had with a penny as a spacer to make it work for now.? I'll run it thru the baseline with PHD2 as soon as I can!
Thanks!
Steve
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Michael Herman
David C. Partridge