Re: Issues with Altitude assembly in older G11
Hi Norm,
This problem is probably caused by there being too much movement in the screw shaft due to a grub screw coming loose. I don't have a CG11 mount but I think the G11 is identical mechanically inside the base. There should be a collar that has a grub screw that locks the collar and thrust bearing retainer, this is what limits the in and out movement of the threaded rod. If the grub screw comes loose the collar may move on the threaded rod allowing too much movement of the threaded rod allowing the brass plug to move which lets the head move fore and aft as you describe. To fix this you need to disassemble the base and get the spacing right and then tighten up the grub screws to hold it in place as it should be. This issue is easily corrected if you have a few hand tools and some patience. Just take it apart and have a look, start at the bottom by removing the big button headed hex bolt and the two locking bolts on the top side of the base. The rest will be obvious once you can see the internal base parts. Keep us posted.
Chip? ?
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Re: Issues with Altitude assembly in older G11
Norm,
Here's an webpage in Italian that shows complete disassembly of G11 mount. You my need to translate. This link is a Chrome translated page.
Don
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----- Original Message ----- From: "normanrevere@... [Losmandy_users]" <Losmandy_users@...> To: <Losmandy_users@...> Sent: Friday, December 29, 2017 5:10 PM Subject: [Losmandy_users] Issues with Altitude assembly in older G11 Hi Everybody,
Ive been a long time lurker of this forum, but I come to you today with a question.
My Celestron branded G-11 rocks back and forth in altitude by 1 notch on the altitude markers. I cant seem to make it stop no matter what I try. I was briefly successful earlier today in making it stop, only for it to break loose again about 20 minutes ago while I was setting up to test it out.
Im going to be trying a few things out and will let you all know if I find a solution. I was hoping that maybe someone among you all has experienced this issue before and knows a fix?
Thanks,
- Norm
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Issues with Altitude assembly in older G11
Hi Everybody,?
Ive been a long time lurker of this forum, but I come to you today with a question.?
My Celestron branded G-11 rocks back and forth in altitude by 1 notch on the altitude markers. I cant seem to make it stop no matter what I try. I was briefly successful earlier today in making it stop, only for it to break loose again about 20 minutes ago while I was setting up to test it out.?
Im going to be trying a few things out and will let you all know if I find a solution. I was hoping that maybe someone among you all has experienced this issue before and knows a fix??
Thanks,? - Norm?
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GM8 Level on Digital Circle mount
Posted a picture of the level I was discussing a while back. The mounting holes are pretty shallow, hence the washers to take up slack. At present the commercial bubble level is attached to the bracket with adhesive. This will be replaced with a tapped aluminum plate when things warm up a bit. Bracket is a short length of 2"x1/8" aluminum angle.?
greg latiak avalon observatory
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Re: G-11G with a stiff RA axis
WOW!!! ?My rig only weighs 13lbs. lol
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With the observatory below -20C, and plenty of wind to make it even better, I was wondering... I have electric heat tapes on my water pipes to keep the lines just above freezing. Has anyone wrapped their mount in this sort of tech to offset the stiffening of the lube? This would only work for AC supplied viewing... although it is a lot like the dew heaters that refractor folk obsess about.
Just curious...
greg latiak avalon observatory
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Re: G-11G with a stiff RA axis
Hi Chip, My G-11 was brand new from the factory in Sept. Maybe the design is a little different, but if you separate the RA on mine there was a groove around the shaft that the wavy washer sits in. It is not actually between the clutch plates but around the shaft. So the washer doesn't touch the plates. It just leaves a little gap when you loosen the tensioner. Which separates the plates enough to let them turn freely.
Greg S.
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Thanks for that nicely done experiment and report on temperature effects.? Now I know the likely cause of my own CG11 viscous motion in both axes.?? As you say, why strain the motors needlessly. I think that the oils in the greases either dry up or flow out (like into those nice clutch disk surfaces), leaving the gummy residue behind.
Next week, I'll be off to clean and relube the system.?? But first I have to find that ziplock bag of Superlube that Chip gifted to me last summer!
Happy new year, all...
Michael
On Wed, Dec 27, 2017 at 10:12 PM, robert@... [Losmandy_users] <Losmandy_users@...> wrote:
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Well, it was the original grease...as far as I can tell. My GM-8 has always been easy to move, but it got stiff and started having trouble tracking when the temp got close to freezing a few weeks back. Today I put it in the freezer and let it chill down. The RA got stiffer, but the Dec was worse. I don't remember it being this bad before. It's only two years old. Anyway, tore it down, cleaned it out and Super Lube'ed it up. The main sticking points were the bearings in the tubes. Put it back in the freezer afterwards and you couldn't even tell it had been in there. Big difference. Now I feel sorry for the motors having to push against that drag all these cool times. Adjusted up the worms too. It was pretty sloppy before. Didn't do anything with the motors or gearboxes. We'll see how things go with just the re-grease. As soon as these high thin clouds go away I'll get to try it out...someday. Thanks all! Bob
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Well, it was the original grease...as far as I can tell. My GM-8 has always been easy to move, but it got stiff and started having trouble tracking when the temp got close to freezing a few weeks back. Today I put it in the freezer and let it chill down. The RA got stiffer, but the Dec was worse. I don't remember it being this bad before. It's only two years old. Anyway, tore it down, cleaned it out and Super Lube'ed it up. The main sticking points were the bearings in the tubes. Put it back in the freezer afterwards and you couldn't even tell it had been in there. Big difference. Now I feel sorry for the motors having to push against that drag all these cool times. Adjusted up the worms too. It was pretty sloppy before. Didn't do anything with the motors or gearboxes. We'll see how things go with just the re-grease. As soon as these high thin clouds go away I'll get to try it out...someday. Thanks all! Bob
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Re: Ovision worm gear assembly does it have a spring washer...may be mssing on mine
Hi Chip,
You are great in 1,000 ways... why its such a nice friendship.?
It's nice and frosty here...snow everywhere.? The high can be 15F one day and the low... negative numbers.? The next day the high can be 40F (people in shorts and tee shirts too).? But snow is always just a day away.? I don't know how anyone does astronomy here... but some folks do. The housing prices are insanely low, but the heating bills must be high to balance out the economy.? Gas prices are about $2.40/gal.? Not in California any more Dorothy!? But there is no beach here so Susan will not consider moving here.
Having fun with Hunter who's at 2.5 a real mensch already.? ? Beth took him to see Nutcracker ballet and he's memorized all the music already.??
We went to see Greatest Showman at the movies and it was a fun movie.? Easy story and the music and presentation reminded me both of LaLa Land and of Hamilton.??
Flying back home on Jan 2... to warmth... though still chilly.? SanJose had a 3.5 quake the other day... still nothing in the 5 or above range... we are way overdue for something to happen.
Have a great New Year!
Michael
On Dec 27, 2017 3:42 PM, " chiplouie@... [Losmandy_users]" < Losmandy_users@yahoogroups.com> wrote:
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Hi Michael,
You know I always forget that people, even people I KNOW are new or new to their Losmandy mount, don't know all of the required bits many experienced people don't mentioning. Thanks for reminding us that you have to start at the beginning to get to the end we are hoping the help people to find.?
So how is it going in the mile high city??
Chip
??
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Re: G-11G with a stiff RA axis
sormborger,
That's strange to me. My G11 at the moment has a Losmandy Side-By-Side with double D saddles in the main saddle. The SBS has a 21 lb and 3 x 11 lb Losmandy counterweights on the end of the CW shaft to balance the payload which is my Celestron NS11 SCT, heavy ES 50mm correct image finder, w/dulal Losmandy "D" dovetails, big 3.29" port 2.5" Moonlite focuser with Celestron f/6.3 SCT reducer-corrector internally and a Canon DSLR screwed on the end of the focuser. In the other saddle I have my Parallax/AT130mm f/6 APO with 14" Losmandy dovetail on the bottom and a 7" Losmandy dovetail on top, FeatherTouch focuser, A-P 2" diagonal with TeleVue 24mm Panoptic and Stellarvue 50mm guidescope with autoguider on top dovetail.The Parallax/AT130 is a heavy instrument, it weighs as much as my loaded up C11 SCT does! This setup exceeds the 60 lb payload capacity as stated by Losmandy but it was easily balanced and when slewing at the default speed setting I see a lag value of 30-40 and my digital bench power supply says the Gemini 2-mini is pulling only 0.8A when slewing and 0.3 when tracking which tells you the rig is well balanced.?
Chip? ?
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Re: G-11G with a stiff RA axis
Yes, my RA axis won't balance accurately the conventional way so by using the worm slop perfect balance can be achieved. ? I learned it from someone else posting this here some time ago. ?It made sense to me so I tried it and I've used it ever since.
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Re: Just purchased GM811GHD
Thanks Chip.? I got the GM8 working quite smoothly. How it actually guides is yet to be seen.??
The G11 in question used an Ovision worm in RA and a stock (ie not high precision) worm in DEC.? So +/- 2 arc sec in DEC was pretty typical, especially in my mountainous environment with relatively poor seeing conditions.? But my set-up was 3.5 arc-sec/pixel.? So I could get away with poor seeing conditions like those shown in the graph of the G11, with very little impact to the final image.
Best,?
Eric
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OFF-TOPIC:LOSMANDY HGM-200 GEM for Sale on Cloudy Nights
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Re: Ovision worm gear assembly does it have a spring washer...may be mssing on mine
Hi Michael,
You know I always forget that people, even people I KNOW are new or new to their Losmandy mount, don't know all of the required bits many experienced people don't mentioning. Thanks for reminding us that you have to start at the beginning to get to the end we are hoping the help people to find.?
So how is it going in the mile high city??
Chip
??
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Re: G-11G with a stiff RA axis
Hi Greg,
My 12 year old G11 has no space to put a wavy washer between the clutch plates nor does my more recent GM8. I had my G11 updated last summer to current G11G specs but have not had any issues balancing my G11 before or after the updates to the the tucked motors etc. I did update the clutch discs to the newer stuff but that did not change balancing at all.?
Chip?
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Re: Just purchased GM811GHD
Hi Eric,
I have always admired your work and it's interesting to hear you are returning to the Losmandy fold. Your G11's logs look less than ideal. I hope your GM8 is working better. Keep us posted on your progress and results!
Chip ??
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Re: G-11G with a stiff RA axis
Thank you, Greg. I¡¯ll give Scott a call today.
Glenn
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Re: G-11G with a stiff RA axis
Glenn, the washer you are using on the shaft right now may not be the correct size for the clutches. Order the right one.
Greg S.
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Re: G-11G with a stiff RA axis
Yes. I called Losmandy and they told me about the missing washer. Trust me, put it in and all will be well. And it's FREE. You have to love free. the plates are just a bit tight and with that washer to seperate them a whisker it works great.
Greg S.
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Michael Herman
Eric Chesak
John