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Polaris (Not a HARA :-) mount questions

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#1 ffraley

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Posted 03 September 2013 - 01:22 PM

Set this up last night, some clouds but really wanted to play with it. A couple of questions:

The attached pic shows the altitude/latitude adjustment screw and casting. Even being unfamiliar with this mount the problem was obvious. I took the part off and it appeared to be cracked. The area around the threaded hole broke off when I tried to straighten it enough for the wing nut to clear the base. I have seen mentioned that this is a weak point on these mounts, someone mentioned rigging a solution when theirs broke. Does anyone know a source for this part, or could they explain how to best work around it? There seems to be some creep when I just tighten things to hold - I also worry I'm just overstressing another part and maybe causing another break of some sort.

Is the chain at the feet original? I don't see it in other photos here. Maybe just on the taller refractor legs?

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#2 hottr6

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Posted 03 September 2013 - 02:58 PM

Sorry, no advice on the alt-adjuster, other than NEVER USE THE SCREW ALONE WHEN ADJUSTING ALTITUDE! The mount is made from cast aluminum, and cannot tolerate much abuse. When I adjust the altitude, I support most of the weight and when I get the angle right, I just use the screw as a marker and then tighten the main adjustment bolt.

Of course, this advice is too late for you now. :foreheadslap:

The chain is not original, and as I remarked on your other thread, I don't think the legs are original to the Polaris.

The Polaris came with a small triangular black tray. This tray is substantially smaller than the larger Vixen trays now available for the Great Polaris and it's variants. The big tray will fit the Polaris.

Photo shows the Polaris and a modern Chinese clone. The Polaris has the small tray, the clone comes with the bigger tray.
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#3 ffraley

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Posted 04 September 2013 - 05:11 PM

'Twas too late before it was mine, that photo was from the first time I assembled it :-) There was visible cracking on the back side, that was why I didn't worry about breaking it since it was doomed. Cracked aluminum castings don't last long in my experience, and will fail at a bad time.

Wherever then legs came from I am impressed. There is a thin metal plate that slides in the groove, it's a very solid arrangement. Any vibrations damps almost immediately. They are pretty heavy, though. I suspect they will look pretty nice stripped and stained.

The driver is working. It only came with AC, need to come up with a battery pack. The polar scope from my CG-4 does not fit, but just eyeballing Polaris through the axis should work well enough for a novice visual user, I hope.

#4 gmussman

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Posted 04 September 2013 - 07:31 PM

I think I've read that the astroview polar scope fits after a fashion, which wouldn't surprise me because the design is similar. Does anyone know for sure?

#5 hottr6

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Posted 05 September 2013 - 06:53 AM

Another little tip. Your counter-weight shaft is heavily corroded, and the threading is a PITN, especially if you use different OTAs on the same mount. A counter-weight shaft from the CG5 threads right on, so you can use any counter-weight with a 21mm hole. Try the shaft from your CG4.... it may be the same.

#6 hottr6

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Posted 05 September 2013 - 06:54 AM

I've read the same about the iOptron polar finder. I've not tried it, however.

#7 Nippon

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Posted 05 September 2013 - 08:30 AM

The altitude adjuster broke on my Polaris and I fashioned one from the speedometer bracket from an old exercise bike. The speedometer bracket was made of steel and it worked fine and was still fine when I sold it 18 years later.






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