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EQ3/EQ5 RA drive on Super Polaris?

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#1 mcoren

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Posted 27 December 2010 - 07:43 PM

I have a Vixen Super Polaris and I'd like to add an RA drive. I know the SP is more of an EQ5-class mount, but the EQ5 drives out there (SkyWatcher, Orion SkyView Pro/TrueTrack) seem to be better suited to the current GP configuration. Can these be hooked up to an SP mount? Would it be easier to hook up an EQ3 drive (e.g. SkyWatcher EQ3-2, Orion AstroView/EQ-3M)? Has anybody tried using a modern EQ3 or EQ5 drive on an SP?

Thanks in advance!

#2 Trev

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Posted 27 December 2010 - 10:02 PM

The Skywatcher EQ4/5 motors will hook up. I believe Joe O'Niel tested it a couple years ago when comparing the Skywatcher vs Vixen motors.

#3 John Carruthers

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Posted 28 December 2010 - 07:34 AM

any drive intended for a 144 tooth crown wheel will work. Meade lxd motors are commonly fitted to SPs to give goto.

#4 mcoren

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Posted 28 December 2010 - 12:32 PM

Trev, John, thanks for that information. Regarding Joe O'Neil's tests, I was able to find this page, which is also quoted here. However, these seem to be talking specifically about the GP mounts, rather than the SP.

#5 SteveG

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Posted 28 December 2010 - 12:47 PM

The only difference between the SP & GP drive motors is the covers. The SP motor is exposed, and uses a small black plastic cover for the gears. The GP uses the same MT-1 motor, and has a large plastic cover that encloses the motor and gears.

#6 mcoren

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Posted 28 December 2010 - 08:49 PM

Thanks Steve! Judging from your equipment list, I think I can take your word on that. :)

So here's a related question for you: On the bottom of the RA axis housing, just below (behind) the RA lock knob and the worm gear shaft, there are three hex screws. The outer two are the small thin type that look like they're holding something on or together, and should not be messed with. The center one has a big, bright, inviting, shiny metallic head. Is this center one used to hold the drive motor on, or will something horrible happen if I loosen it?

Thanks again!

#7 SteveG

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Posted 29 December 2010 - 01:54 PM

Mike

I'll have to take a look, but I'm pretty sure it's just the one shiny allen bolt that holds the motor in place. I just upgraded my GP mount to a Vixen motor that I was lucky to find cheap. I removed the Orion motor by loosening that bolt - pretty sure the SP is the same.

Here is a pic of the GP with the motor installed. You will note that it's not a perfect fit as the motor sits at an angle.

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#8 SteveG

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Posted 29 December 2010 - 01:55 PM

And a close up....

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#9 Brian Risley

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Posted 29 December 2010 - 05:21 PM

I think the hex screws you are looking at are for adjusting the RA Worm. You should see a similar set on the dec axis. Once motors are mounted, these are not accessible.
Brian

#10 Brian Risley

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Posted 29 December 2010 - 05:40 PM

One of the differences between the SP/new SP and GP mounts had to do with how the motors were attached. On older SP mounts, there was a small dovetail held in by four screws located outside the ra motor mount area and on the dec axis there was the motor mount plate that held these. Newer SP/GP mounts put the dec mount permanently on the head. The newer SP/GP mounts I also believe use the through the bottom of the motor mounting method vs the screws against the dovetail.
If you have a cover over the RA mount point, take it off and see if you have a hole through the mount for the motor screw. If you don't you may need to fashion a dovetail mount bracket to attach one of the motors made for the newer style mounts that only used the single screw.
Brian

#11 mcoren

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Posted 29 December 2010 - 09:49 PM

OK, thanks. I think I understand now. I think what I have is one of the "older" SP mounts with the spot for the dovetail. Still, I was able to relate Steve's picture to my mount. I also found a good exploded assembly drawing of the SP mount here, so now I understand how the motor mounts.

I went ahead and ordered the Orion TrueTrack drive from Adorama, but it's backordered so I probably won't get it for about two weeks (probably will be ground shipped from CA to NY first. So much for ordering from and East Coast place!).

Thanks again everyone! I'll let you know how the installation goes.

#12 Geo.

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Posted 01 February 2011 - 10:51 AM

Mike, I put some Synta CG-5 (EQ-4) drives on an older SP. See my photos of the project here:
http://groups.yahoo....620213/pic/list

HTH, George

#13 Geo.

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Posted 01 February 2011 - 10:55 AM

Oh, BTW, most of the fasteners on the older SP are Imperial with 1/4-20 being common. So you can replace those Vixen screws with the bad chrome with nice Home Depot stainless.






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