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Improving Polar Alignment Adjuster Mechanics

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#1 Patrick

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Posted 06 June 2013 - 02:01 PM

I have a CGEM mount which has a very good altitude adjustment knob on it. I have zero issues with precisely placing the altitude where I want it.

However, the azimuth adjustment mechanism is a real pain in the behind. To make adjustments in azimuth I first have to loosen the main center bolt slightly and then fight the two opposing screws back and forth...back and forth...to align the azimuth. It's sometimes a struggle because of overshooting the mark and then having to back off one screw and retighten the other one. When I do get it where I want it, then I have to tighten the center bolt which can throw off the alignment in both directions. So, I have to make sure not to loosen the center bolt very much which makes adjustment in the azimuth that much more difficult.

There has to be a better way! :confused:

Does anyone have any tricks or techniques that would make it easier to adjust the azimuth alignment on a CGEM?

Thanks,

Patrick

#2 Hilmi

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Posted 06 June 2013 - 02:53 PM

I had a similar problem back when I used to use a wedge with my LX200r. Then I purchased a third party upgrade with less backlash and it made all the difference.

#3 starbob1

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Posted 06 June 2013 - 03:23 PM

Yes that is a pain. I also use a cgem. But I sprayed my bolts with WD40 to help some with adjusting. I also just slighty loosen the center bolt'just enough to move the mount. Just part of it I guess. Bob

#4 rmollise

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Posted 06 June 2013 - 03:26 PM

With both the CGEM and the Atlas, loosening the bolt that holds the head to the tripod when you are polar aligning is just a fact of life. Once it's tightened down, you'll find you can still adjust azimuth a little bit if it's been thrown off by the tightening.

#5 Footbag

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Posted 06 June 2013 - 03:44 PM

With my CPC, I made the final small adjustment with the wedge tightened down. It makes the small movements easier.

#6 WesC

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Posted 06 June 2013 - 03:48 PM

Yeah I was dealing with this frustration last night. And having an unlighted polar scope doesn't help.

#7 Mert

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Posted 06 June 2013 - 04:46 PM

Adjusting Azimuth on my EQ6 used to be a pain, after
which I took some sanding paper and sanded slightly
both surfaces that rub against each other.
Then applying a bit of white grease ( little bit ) and
now I can adjust even with the head fully locked down
onto the tripod, still moving very smooth!
Maybe an idea :shrug:???

#8 gustavo_sanchez

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Posted 06 June 2013 - 04:54 PM

I have this same problem with my Sirius EQ-G when mounted in a CGEM tripod. However, if I use the SVP pier accessory between the two, then I don't have any problems at all. The mount head - pier top interface is much smoother than the mount head - tripod hub interface.

#9 Patrick

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Posted 06 June 2013 - 09:43 PM

I took some sanding paper and sanded slightly
both surfaces that rub against each other.
Then applying a bit of white grease ( little bit ) and
now I can adjust even with the head fully locked down
onto the tripod, still moving very smooth!



The mount head - pier top interface is much smoother than the mount head - tripod hub interface.



Interesting. I think both of you guys are suggesting that the frictional forces between the bottom face of the mount head and the surface it's sitting on (tripod or pier) play a significant role in how easy it is to make azimuth adjustments. I had not considered that, but it certainly makes sense. I'm going to have to take a serious look at those interfaces to see what I can do to reduce the friction. I have a slightly different setup because of my pier plates.

Thanks!

Patrick

#10 rkayakr

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Posted 06 June 2013 - 10:12 PM

As an alternative to the polish and grease approach I have used the trusty milk carton plastic ring (old dobs secondary adjustment trick) to make a low friction surface to ease azimuth adjustment on several GEMs. I also use molybdenum disulfide dry lube on the adjustment bolt threads and crown the ends for smooth contact.

#11 RTLR 12

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Posted 06 June 2013 - 10:25 PM

I use UHMW Film tape on top of the tripod. Makes movement very easy even with the center bolt tight.

Stan

#12 Patrick

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Posted 06 June 2013 - 11:51 PM

I use UHMW Film tape on top of the tripod.



That sounds like a good idea.

Patrick

#13 cuivienor

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Posted 07 June 2013 - 06:02 AM

I put my mount on a sturdy photo tripod with central column (fully retracted). There is always a bit of play in azimuth when the column is slightly unlocked, and I use that play to make the final adjustments.

#14 samm

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Posted 07 June 2013 - 06:17 AM

would this work: putting a cd disk between the top of the tripod and the bottom of the head ?

#15 rmollise

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Posted 07 June 2013 - 07:10 AM

would this work: putting a cd disk between the top of the tripod and the bottom of the head ?


Might. But a simpler solution, which I used, was to apply a very thin layer of bicycle chain grease. Probably didn't need to, but it does make the azimuth smoother.

#16 lukasik

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Posted 07 June 2013 - 08:37 AM

Hi Patrick,

Similar to sugggestions above I used .020" polyester shim stock from McMaster Carr to make a washer between the mount and tripod for my C5 clone. I also made a new knob with a thrust bearing to hold it all together. The addition of the thrust bearing allows the assembly to remain tightly clamped and still have very fine control over azimuth adjustments.

Best Regards,

Bob

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#17 lukasik

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Posted 07 June 2013 - 08:37 AM

#2

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#18 lukasik

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Posted 07 June 2013 - 08:38 AM

#3

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#19 Patrick

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Posted 07 June 2013 - 08:48 AM

Thanks for the pics, Bob! I'm now thinking I may have to do a complete overhaul on the azimuth interface.

As I'm thinking about and researching this, the traditional 'post' with counter acting screws is probably not the best mechanical arrangement.

I came across the Malco 360 Degree Rotating Pier Platel for AP mounts. I wonder if something like that could be adapted to a CGEM.

Patrick

#20 DaveJ

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Posted 07 June 2013 - 09:09 AM

Does anyone have any tricks or techniques that would make it easier to adjust the azimuth alignment on a CGEM?


Sure do! Link. A fellow NE Ohio CGEM owner and I got a 1' piece of this stuff each. We cut donuts out and installed. No more azimuth adjustment problems - at all. With the center bolt fully tightened, the azimuth adjustments are now smooth as butter - actually feels like it's on bearings!

#21 EFT

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Posted 07 June 2013 - 09:53 AM

Lots of possibilities here. Smoothing both surfaces is one, but they need to be smoothed flat which may be difficult and two flat surfaces can "stick" together so lube may be necessary.

Lube by itself is a possibility but only one I would use on a mount that is not going to be removed from the tripod since dirt will get in there and make things worse.

Plastic from a milk jug is cheap and seems to work reasonably well. I have cut thick PTFE bearings for people to put between the mount and tripod and that seems to work very well.

TPI Astro is considering making an adjuster similar to the one they made for the CGE but for the EQ6. Ideally, this should work for the CGEM as well. It will not be cheap, but it will allow for very fine adjustment.

#22 Edmond S.

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Posted 07 June 2013 - 02:05 PM

I use PTFE sheet between my mount and the home-made wooden pier plate, and add some lithium grease on the azimuth bolt screw. It works pretty well.

#23 Alph

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Posted 07 June 2013 - 02:30 PM

Does anyone have any tricks or techniques that would make it easier to adjust the azimuth alignment on a CGEM?


Sure do! Link. A fellow NE Ohio CGEM owner and I got a 1' piece of this stuff each. We cut donuts out and installed. No more azimuth adjustment problems - at all. With the center bolt fully tightened, the azimuth adjustments are now smooth as butter - actually feels like it's on bearings!

Have you tried that on the CGE?

#24 DaveJ

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Posted 07 June 2013 - 03:01 PM

Does anyone have any tricks or techniques that would make it easier to adjust the azimuth alignment on a CGEM?


Sure do! Link. A fellow NE Ohio CGEM owner and I got a 1' piece of this stuff each. We cut donuts out and installed. No more azimuth adjustment problems - at all. With the center bolt fully tightened, the azimuth adjustments are now smooth as butter - actually feels like it's on bearings!

Have you tried that on the CGE?


No, I haven't since the CGE never caused me much grief in AZ adjustments, at least not nearly as much as the CGEM DX. Now you've got me thinking... :grin:

#25 EFT

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Posted 07 June 2013 - 03:24 PM

Does anyone have any tricks or techniques that would make it easier to adjust the azimuth alignment on a CGEM?


Sure do! Link. A fellow NE Ohio CGEM owner and I got a 1' piece of this stuff each. We cut donuts out and installed. No more azimuth adjustment problems - at all. With the center bolt fully tightened, the azimuth adjustments are now smooth as butter - actually feels like it's on bearings!

Have you tried that on the CGE?


The CGE uses an internal adjustment mechanism whose problem is the very coarse adjustment mechanism itself as opposed to two painted metal plate rubbing together. No at all the same problem as a CGEM or Atlas mount and cannot be solved in the same manner.






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