Jump to content


Photo

Vixen Polaris GEM mount stripped gear advice

  • Please log in to reply
6 replies to this topic

#1 RingleaderO

RingleaderO

    Lift Off

  • -----
  • Posts: 5
  • Joined: 21 Nov 2012

Posted 22 November 2012 - 01:20 AM

Hey ya'll,

First time posting here, it's good to see so many fellow telescope enthusiasts! I recently acquired a Celestron SP C102, same as this one:

http://www.astromart...99/300691-1.jpg

Recently, I've been having some rather troubling issues with my Vixen Polaris GEM mount.

When I rotate the azimuth control knob, the gear slips, and doesn't rotate the top section as it should. Not only that, but everything above that control knob can be moved up or down by a slight push, when it shouldn't be able to move at all. I disassembled it and it appears as though this gear is partially stripped:

Posted Image

Not the smaller gear spindle, the larger hollow cylindrical one to the right, which appears to be made of aluminum or steel.

I wiped all the grease off both gears, which had a lot of ground up metal shavings in the teeth, and cleaned up both ends thoroughly. It actually doesn't LOOK like it's stripped, it doesn't really appear damaged at all, but I know for for a fact it's stripped. Not knowing what to do next, I applied some Vaseline (I didn't have the right grease for the job), and put it back together, but sure enough it would slip when rotating the azimuth control, and if I tightened bolt holding the 2 gears together too tightly, it wouldn't rotate at all, so no threshold between locked and slipping.

I opened it up again, and the metal shavings were back with a vengeance. I'm really at a loss here, after cleaning out the gears and putting it all back together, they still slip, or don't want to turn at all. I have an idea of how to fix this, but it involves several hours and a dremel, and I would rather try something else if possible.

Has anyone had this problem before, or does anyone know how to fix this?
















Also, I'm not a big fan of the Polaris GEM mount, it's heavy, it's hard to move around, and as you can see, it's been giving me some problems lately. It's around 30 years old at this point, and I'm looking to upgrade to something a little better.

Do you know of any particular mounts that fit the Celestron SP C102, and that:

1. are cheap
2. have some kind of smooth, computer controlled tracking system
3. are relatively lightweight
4. are easy to move around, have telescopic legs, etc.
5. are the color black (not that important)

#2 RTLR 12

RTLR 12

    Aurora

  • *****
  • Posts: 4577
  • Joined: 04 Dec 2008
  • Loc: The Great Pacific NorthWest

Posted 22 November 2012 - 01:56 AM

What do you consider cheap? Cg-5GT Celestron...$400 to $500 used.

Stan

#3 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5720
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 22 November 2012 - 02:09 AM

there's a sky view pro on the classifieds for $300. includes half pillar and dual axis drive.

The CG-5 ASGT is the cheapest goto you can get. But if you think it's lighter than your Super Polaris, you'll be unpleasantly surprised.

#4 EFT

EFT

    Vendor - Deep Space Products

  • *****
  • Vendors
  • Posts: 2565
  • Joined: 07 May 2007
  • Loc: Phoenix, AZ

Posted 22 November 2012 - 01:07 PM

If the gears are in fact damaged, your only option will be to find another mount of similar vintage and scavange parts from it, after you figure out why it was happening in the first place. Also, as you recognized, you need the correct grease. Overall, I can't see making the investment in this mount.

If you want to switch to goto of similar size, the best choice is the CG-5GT. Non-goto would include some of the small Orion GEMs.

#5 Starhawk

Starhawk

    Space Ranger

  • *****
  • Posts: 5614
  • Joined: 16 Sep 2008
  • Loc: Tucson, Arizona

Posted 22 November 2012 - 05:48 PM

You need to know how it got damaged. This is a bit difficult to explain, especially on Vixen gears.

-Rich

#6 hottr6

hottr6

    Mercury-Atlas

  • *****
  • Posts: 2514
  • Joined: 28 Jun 2009
  • Loc: 7,500', Magdalena Mtns, NM

Posted 23 November 2012 - 08:50 AM

Thread tag is inconsistent with OP. Thread tag mentions the Vixen Polaris, but the OP is about the Super Polaris. Big diff.

#7 Geo.

Geo.

    Gemini

  • *****
  • Posts: 3042
  • Joined: 01 Oct 2008
  • Loc: Upstate NY

Posted 25 November 2012 - 01:56 PM

I'll swap you a nice CG-5 for the SP. Your tripod weights and weight shaft can be used with the CG-5. PM me if interested.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics