Re: DEC axis a bit stiff on G-11
Chris my washer is in the position you speak of. Even when the nut is totally loose it is still stiff. I don't know why and either does Losmandy. But I do know that it is hard to get a good balance when the dec shaft doesn't move until it's way overweighted.
Greg
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Re: DEC axis a bit stiff on G-11
Read my problems on "High Worm Torque". If the wavy washer is next to the baring race(that is how it comes from Losmandy), move it to under the out to under the nut on Dec. & RA. The wavy washers are too large for the bore and scrape on the shaft. Chris
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DEC axis a bit stiff on G-11
My G-11 is about 2 months old. Bought it right from Losmandy so it has all the new updated parts. My problem is the dec axis seems a bit stiff. I had to order the curly spring washer for the RA axis to make it swing easy when doing a balance setup. I asked if they make one for the dec axis but they said no. So is there any way to make the dec axis move a little easier? When trying to balance in dec the mount is so stiff it's hard to get it right. I have to have it pretty overloaded on one side to get it to swing in that direction. And yes I did loosen the nut all the way to loosen it up.
Greg
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Forgot to give you depth:. ?7.5 to 8" would work.
On Sep 26, 2017 10:11 AM, "Linda Thomas-Fowler linda@... [Losmandy_users]" < Losmandy_users@...> wrote:
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Can anyone tell the approximate length x width x depth for the gm811g mount? I¡¯ve got one on order and need to figure out what I¡¯m going to transport it in. Alas, the website doesn¡¯t provide that info so I¡¯m hoping someone here can enlighten me.
Thanks!
Linda
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Just bought a G811G.
I would allow for 19" H by 15" W by itself.? Odd shape in a box, not rectangle, you know. This is just the two heads together without the 16" CW bar or mount and cup. Trpods all different sizes.
Astromeb
On Sep 26, 2017 10:11 AM, "Linda Thomas-Fowler linda@... [Losmandy_users]" < Losmandy_users@...> wrote:
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Can anyone tell the approximate length x width x depth for the gm811g mount? I¡¯ve got one on order and need to figure out what I¡¯m going to transport it in. Alas, the website doesn¡¯t provide that info so I¡¯m hoping someone here can enlighten me.
Thanks!
Linda
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I have a GM-8 in a Pelican iM2750 and that could probably handle a full G-11, especially now that the motors are tucked in. You can look for the dimensions for that box. I have room in there for a pie tin that I use for a tray on the tripod and other stuff. I've got the counterweights and the extension tube in another box.
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Can anyone tell the approximate length x width x depth for the gm811g mount? I¡¯ve got one on order and need to figure out what I¡¯m going to transport it in. Alas, the website doesn¡¯t provide that info so I¡¯m hoping someone here can enlighten me.
Thanks!
Linda
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Wow, thanks, I wish I had Wilmslow's info about 6 months ago, thanks. Note, a friend just emailed me, his washer is over size too. Chris
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Hi Guys,
Yes, I'm with Chip on the parts order... and so does Mark Crossley, who has put nice photos at his website: ?
The images are here:
The top photo shows the original (now thought wrong) order, and the photo below it with the wavy spring washer between the clutch knob and the black thick disk (now thought more correct).
Best, Michael
On Sep 25, 2017 19:50, " christystrang@... [Losmandy_users]" < Losmandy_users@yahoogroups.com> wrote:
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It does.?When I disassembled the unit I looked at the thin bearing washer and said, that is not good, but Losmandy has been making quality mounts for a long time so it must be ok. I thought
this arrangement most likely would keep the clutch clean. But I did put the wave washer next to the nut. I am thinking I should make felt packing to help keep the open clutch clean. I still may have a small alignment problem
so if someone knows if the bearing blocks are removable please let me know or a drawing.
Chris
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It does.? When I disassembled the unit I looked at the thin bearing washer and said, that is not good, but Losmandy has been making quality mounts for a long time so it must be ok. I thought
this arrangement most likely would keep the clutch clean. But I did put the wave washer next to the nut. I am thinking I should make felt packing to help keep the open clutch clean. I still may have a small alignment problem
so if someone knows if the bearing blocks are removable please let me know or a drawing.
Chris
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Re: GM8 Guiding near meridian
Maybe related?
I find that once PHD2 loses its tracking, it doesn't even try to retrack.
I even had the weird situation that it was tracking and seemed fine, then just stopped tracking. It did that several times after I told it to track.? ( I have the "star mass" item turned off...no idea why that even matters. )?
In that last case I cleared the existing calibration, and told it to recalibrate.? That seemed to work... so watch your PHD2 screen for at least one full sub after you turn it on.? Once it loses autoguiding, you can get all kinds of star track zigzags.
Best, Michael?
On Sep 25, 2017 16:05, " cbradshaw1@... [Losmandy_users]" < Losmandy_users@...> wrote:
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I did check for cable snags, which was my first thought, but everything seemed OK.? Balance seemed good, but I could have had some sliding in the dovetail.? I had to rebalance after I placed a 2" extender to obtain focus.
Thanks,
Charlie
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Re: GM8 Guiding near meridian
I did check for cable snags, which was my first thought, but everything seemed OK.? Balance seemed good, but I could have had some sliding in the dovetail.? I had to rebalance after I placed a 2" extender to obtain focus.
Thanks,
Charlie
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Thanks for the information. Good to hear it should perform at or better than the G11G.?
toggle quoted message
Show quoted text
From: Losmandy_users@... on behalf of chiplouie@... [Losmandy_users]
Sent: Saturday, September 23, 2017 3:39 PM
To: Losmandy_users@...
Subject: [Losmandy_users] Re: GM811G AP Questions
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Hi Bill,
The GM811G is just a G11G bottom with a GM8 top. So the tracking will be just as good if not better than the G11G because the RA axis does all the work once you are on an object and the G11G base is more than capable of carrying a 60lb. payload and in
this application Losmandy has underrated the drive to fit a spot in the new mount lineup.?
Chip?
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Re: GM8 Guiding near meridian
Hi Charlie,
First, I am glad you said that your guiding up to the meridian was excellent.? That says all of your hardware and software and electronics are working perfectly. ?
As for the problem itself, I think your counterweight or dovetail balance may have not been exactly on the mark.
When you are pointing at the meridian, the scope is on its maximum lateral extent and the counterweight is at the other end.? If there is a weight imbalance between them, the RA motor and clutch must exert the highest force at that position.? When you are at CWD, there is essentially no force on the RA axis or DEC axis, as these forces are taken up by the mechanics of the bearings. ?
Secondly, check your cabling, etc for any snags...those are common issues in the dark, as the scope is moving things can snag up. ?
Third, check your clutch holding ability.? If you bump your scope does the RA or DEC axis move?? If so I'd be wary of the small 3 inch OD 1.25 inch ID clutch disks of the GM8. ? I have made far better holding clutch disks; if interested contact me.
All the best, Michael
On Mon, Sep 25, 2017 at 2:27 PM, cbradshaw1@... [Losmandy_users] <Losmandy_users@...> wrote:
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Saturday night I started imaging, guiding with PHD2 (the guide log image has been uploaded).? For the first hour, guiding was perfect.? I then had some severe jumps, but it settled down.? Then, as it approached the meridian, I had sever swings and overshoots.? I changed exposure, aggressiveness and min motion without success.
I'm thinking my GM8 backlash is bad.? Any other suggestions?
Regards,
Charlie
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GM8 Guiding near meridian
Saturday night I started imaging, guiding with PHD2 (the guide log image has been uploaded).? For the first hour, guiding was perfect.? I then had some severe jumps, but it settled down.? Then, as it approached the meridian, I had sever swings and overshoots.? I changed exposure, aggressiveness and min motion without success.
I'm thinking my GM8 backlash is bad.? Any other suggestions?
Regards,
Charlie
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Hi Chris,
The wavy spring washer should not be located where it is constrained by its OD! As delivered Losmandy mounts place the wavy spring washers directly working on the outer bearing race. Many people, myself included, see this as an odd assembly order as this placement localizes wavy washer spring pressure on the relatively thin thrust bearing race which should never happen in this sort of assembly.? ? So the common wisdom assembly order used by many mechanically inclined folks is as follows, on the RA axis starting from the outside and moving in toward the mount: polar scope cap-clutch knob-spring washer-thick black anodized aluminum RA spacer-outer thrust bearing race-caged needle bearing-thrust bearing race-mount seat for race. The Dec axis is the same sans the polar scope cap.? ? Some thing to be aware of, I have cleaned and re-lubricated several Losmandy G11 and GM8 mounts owned by many different people from many different generations of Losmandy production. I have seen only these two variations in the assembly order and sometimes an additional thicker bearing race washer on RA and/or Dec axes. I don't know why this is or even if Losmandy supplied the mounts in this condition. I only noted the differences and assembly order and put them back as I found them with the wavy spring washer in the outer position, they seem to work fine once reassembled and tested. ? I hope this helps!
Chip
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? For those who care. My major problem with high torque was the wave-washer. It had an OD of 51.01 mm and the bore of housing is 50.80 mm. An interference that when assembled restricting
shaft rotation. This was depicted by large scrapes on the shaft. The strange thing is the scrapes were only on one side, which would indicate I may also have some of the same problems Eric had. This could not be confirmed
because a dial indicator read less than 0.0005 inches run out, which is the limit of accuracy of my setup. I ground down the OD of the washer, but, the easiest thing is just put it next to the knob. I would like to have
an assembly drawing but can¡¯t find one. Also, do the blocks that hold the shaft bearings come off? I posted an image, look in photostream or Chris Strang.Eric, thanks for the thought.
Chris
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Hi Chris,?
Hope your wife has a speedy recovery.
Eric
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Thanks Eric for the follow-up note. I will look at it when I can, my wife is very ill in the hospital and my astronomy is on the back burner. I have the precision tools and
skill to make the repairs if I can find the problem. I started this ¡°topic¡± by asking if the clutch should influence the worm torque, and the answer is no. As I remember, there was no indicators of rubbing and the worm turn
the shaft nicely with low clutch loading, but I will recheck as to your suggestion.
Chris
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Re: Does anyone know what would cause a Zig-Zag star trail in photos?
Best not to cross post between losmandy/Gemini yahoo forums. especially since the photos are on the other group forum.?? Obviously there is some worm zig zag but I'm not the best at actual operational adjustments to comment, others will...probably best on other forum.
Also best to use a signature or name at end of post for others to address you when replying, it just good etiquette.? Don't fret your not the first or last ever to do this..
regards
Brendan
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Mearl Balmer
Michael Herman
Eric Chesak