Telescope Reviews: Vixen Polaris load capacity

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Equipment Discussions >> Mounts

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orlyandico
Carpal Tunnel

Reged: 08/10/09

Loc: Singapore

Re: Vixen Polaris load capacity new

[Re: greju]
#5109800 - 03/07/12 12:59 PM

here's one for laughs.

I got an M16 threaded rod (really long) and used that as a C/W shaft.

Then I put a C9.25 on it (in the daytime).

Took it right off.

I also have a GP and it's marginal for the 9.25 even for visual. I don't think the Polaris has the same worm wheel diameters as the GP - the axes are noticeably smaller. Although I didn't take apart my Polaris before selling it.

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SteveG
Post Laureate

Reged: 09/27/06

Loc: Seattle, WA

Re: Vixen Polaris load capacity new

[Re: orlyandico]
#5109837 - 03/07/12 01:14 PM Attachment (62 downloads)

ED100 f9, no problem!

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Starhawk
Post Laureate

Reged: 09/16/08

Loc: Tucson, Arizona

Re: Vixen Polaris load capacity new

[Re: SteveG]
#5111283 - 03/08/12 09:14 AM

The C8 is really light- remember, it can go on a Universal Astronomics Unistar mount, which is quite dainty compared to the Vixen Polaris.

I modified mine to accept a CG-4 drive system. The Dec axis required a tab to attach the motor to, but has an angled part which makes this easy. The RA was substantially more difficult because the CG-4 has 130 worm wheel teeth and the Vixen has 144. So, I had to find some gears to gear up at 11:10 ratio. I found them at a site selling robot parts. It works quite well, though I had to find stickers to invert the N and S on the drive controller.

-Rich

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JIMZ7
Pooh-Bah

Reged: 10/22/05

Loc: S.E.Michigan near DTW

Re: Vixen Polaris load capacity new

[Re: Starhawk]
#5127948 - 03/18/12 12:57 AM

Today I put the Vixen Polaris mount in alt-az.mode and took off the 6 lb.counterweight. It is so easy to carry now with my 4" f/9.8 refractor. The scope can easily rotate 360-degrees which saves on your back from lifting the entire scope when viewing something else. Very nice to observe while relaxing in a chair.

Jim

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ohioalfa64
member

Reged: 08/16/12

Loc: Ohio

Re: Vixen Polaris load capacity new

[Re: JIMZ7]
#5537461 - 11/24/12 04:10 PM

Is there a photo of a C8 on the Vixen Polaris. I am considering mounting my ETC125 on this GEM.

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orlyandico
Carpal Tunnel

Reged: 08/10/09

Loc: Singapore

Re: Vixen Polaris load capacity new

[Re: ohioalfa64]
#5537473 - 11/24/12 04:18 PM

I saw a photo somewhere when I still had my Polaris.

I think the ETX125 will be not a problem at all. It is short physically and presents a small moment arm.

I have not tried a C8 on the Polaris. The C9.25 was way too much, a 100ED is ok-ish, still not optimal, but can be lived with. The 100ED has a 1-meter long tube, so the ETX125 should not pose a challenge at all.

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Ducky62
professor emeritus

Reged: 10/31/10

Loc: The ATL

Re: Vixen Polaris load capacity new

[Re: greju]
#5538020 - 11/24/12 11:03 PM

Quote:

Quote:

Used mine last night - extremely lightweight and reasonable stable. I added a simple Celestron motor drive for tracking.

A four year old thread and finaly a picture! Carved out of a solid block of aluminum this one may have a higher payload but I still would not stick a C-8 on it.

Hey! You have the early "New Polaris". What 'scope came on that? I have 3 Polaris mounts but only one of them is like the one pictured.No lat scale but it is so much nicer than the later two. So it is milled and not cast? I need one of those original drives. Have you ever measured the PE? I have suspicions the early ones are whole different animals.

Edited by Ducky62 (11/24/12 11:16 PM)

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roscoe
curmudgeon

Reged: 02/04/09

Loc: NW Mass, inches from VT

Re: Vixen Polaris load capacity new

[Re: Ducky62]
#5538365 - 11/25/12 08:09 AM

I have some weight info that I got from somewhere on the net, that lists a Polaris at 10 lbs, a GP at 16, a SP at 18, and a GPDX at 22.
I had a Celestron C-80 on mine, it was fine for that scope.
Russ

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Geo.
Carpal Tunnel

Reged: 10/01/08

Loc: Upstate NY

Re: Vixen Polaris load capacity new

[Re: roscoe]
#5538751 - 11/25/12 01:44 PM

To get the ETX125 to balance correctly the tube's center of gravity should be a little forward of the center of the mount's Dec axis. IIRC the 125 has a rather queer ring size. Probably easiest to add a Vixen format dovetail saddle and a 6" bar to the ETX.

An 11-13 pound C8 is a bit too much I'm afraid. A C4 or 6 would be fine.

I think you'll find that the Polaris is machined from aluminum alloy castings not from billet. As mentioned the RA worm wheel is 130 teeth, think Dec is 70.

The Polaris was sold under Celestron and Tasco scopes. Think the C6 was sold on it. Tasco sold a Synta made drive for it. It was very similar to the EQ-3, CG-4 drive.

I don't understand the comments about early models. There has only been one Polaris configuration. Although, I've seen them in three colors.

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orlyandico
Carpal Tunnel

Reged: 08/10/09

Loc: Singapore

Re: Vixen Polaris load capacity new

[Re: Geo.]
#5538780 - 11/25/12 02:02 PM

i had a polaris and it was definitely 144 teeth...

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zjc26138
Loved By All

Reged: 02/24/05

Loc: Mingo Junction, Ohio

Re: Vixen Polaris load capacity new

[Re: orlyandico]
#5538814 - 11/25/12 02:14 PM

Beside mounting my WO 110 on the Vixen, I also mount a Meade 8in SCT. I forget what model it is. I had the mount setup in Alt-Az. It handled the scope ok. It was better than not mounting the scope at all.

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ohioalfa64
member

Reged: 08/16/12

Loc: Ohio

Re: Vixen Polaris load capacity new

[Re: zjc26138]
#5542484 - 11/27/12 05:04 PM

Thanks for the advice on the ETX-125 mounting. What if instead I attempted at 150mm iOptron Mak on the Polaris? It is 20 inches and somewhere around 14 lbs without the standard Finderscope or Aluminum Dew shield (another 7 inches longer). Instead of answering in yes or no terms, tell me what impact I would face by doing this. Will it break; do I need another weight on the couterbalance, etc. A laser pointer and Astrozap wrap dew shield reduce weight and decrease the forward moment arm. Or am I just creating a monster?

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Geo.
Carpal Tunnel

Reged: 10/01/08

Loc: Upstate NY

Re: Vixen Polaris load capacity new

[Re: ohioalfa64]
#5543039 - 11/27/12 11:01 PM

I wouldn't worry about breaking it with a static load. It might just be a bit shaky, like a C9.25 on a CG-5. The Dec axle is about the same size as the Triumph spindles Chapman used on his early F1 cars. Of course, those spindles did occasionally fail ... no high speed turns please.

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Starhawk
Post Laureate

Reged: 09/16/08

Loc: Tucson, Arizona

Re: Vixen Polaris load capacity new

[Re: Geo.]
#5544752 - 11/28/12 10:51 PM

I just posted the pix of my own vixen Polaris mods in the Super Polaris drive thread.

-Rich

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StarStuff1
Carpal Tunnel

Reged: 04/01/07

Loc: South of the Mason-Dixon Line

Re: Vixen Polaris load capacity new

[Re: Starhawk]
#5544821 - 11/28/12 11:33 PM

Years ago I acquired a used Polaris mount. I called Celestron Customer Service (remember those days?)to ask about the mount capacity. IIRC the lady said 24-25lbs. I was surprised to hear this. The OTA I mounted on it was a 114mm f/12.5 achromat that weighed about 17 lbs fully loaded. Everything worked fine unless there was wind. BUT, I did build a hd wood tripod for the mount as the original mount was for a 6-in f/5 reflector.

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orlyandico
Carpal Tunnel

Reged: 08/10/09

Loc: Singapore

Re: Vixen Polaris load capacity [Re: StarStuff1]
#5544924 - 11/29/12 02:01 AM

24-25lb seems excessive. as i said above, i tried putting my C9.25 (22lb) on the polaris and it was scary spindly... (to the point of unusability)

i guess celestron's penchant for overstating mount capacity (35lb on the CG-5 anyone?) didn't start recently.

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ohioalfa64
member

Reged: 08/16/12

Loc: Ohio

Re: Vixen Polaris load capacity new

[Re: orlyandico]
#5566254 - 12/11/12 04:36 PM

I need more counterweight to balance the 150mm iOptron Mak. I have a 6.5 lber all the way out on the 1/2 threaded shaft (fine threads). I need to find another or make some sort of makeshift weight using nuts/washers to hold it in place. Plobably need another similar 6.5 lber. Luckily its been completely cloudy since I got the Mak.

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gmussman
member

Reged: 09/21/12

Loc: Cincinnati, Ohio

Re: Vixen Polaris load capacity new

[Re: ohioalfa64]
#5566762 - 12/11/12 11:20 PM

I recently added a dovetail shoe adapter from scopestuff to my polaris. It messed everything up, sort of -- My 80's Japanese Tasco 114 f/8 reflector (metal tube) now needs the entire length of the shaft for adequate counter-weighting because it pushes the scope too far out. However, it is still rock-stable, and I haven't abandoned the mod yet. I think without the dovetail shoe bracket, a light 6 inch reflector would do fine.

On a different note, a few people have thrown drive comments in their posts -- I modded an eq-3 drive with an uprated crystal to compensate for the 144 teeth on the polaris versus 130 on the EQ-3. It was a $1 fix, and it tracks great.

I'm pretty sure that makes it the only cheap thing I've ever done with a telescope ...

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Geo.
Carpal Tunnel

Reged: 10/01/08

Loc: Upstate NY

Re: Vixen Polaris load capacity new

[Re: gmussman]
#5571132 - 12/14/12 04:46 PM

There were two different length counter weight shafts sold with the Polaris, one about 8" and the other about 12. Any GP clone 19mm CW shaft will work with the Polaris. The Meade LXD55/75 shafts are nice as they are a little longer than most.

Quote:

I modded an eq-3 drive with an uprated crystal to compensate for the 144 teeth on the polaris versus 130 on the EQ-3. It was a $1 fix, and it tracks great.

Can I ask what the frequency of the crystals were and are? Thanks.

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gmussman
member

Reged: 09/21/12

Loc: Cincinnati, Ohio

Re: Vixen Polaris load capacity new

[Re: Geo.]
#5571195 - 12/14/12 05:24 PM

This is a nice page with pictures of the procedure on the single-axis drive for an EQ-1, which only has 100 teeth so the calculation has a different result but is done the same way.
I did the same procedure with with the EQ-3 dual-axis (and made a declination bracket as well). I think the original crystals are the same 3.56 MHZ. By my calculation, I needed a 3.96 MHz chip, but to custom make one was like $50, and a 4.0 MHz was $1. The tracking difference is a few arc-minutes per hour, more than adequate for visual or (probably) guided AP, though it'd have to be an awfully light guide rig to go on the mount.

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