tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3135625 - 05/30/09 10:28 AM
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
The gotonova kit arrove yesterday. When I can scare up some time, I'll start working on making the conversion.
The hand paddle is smaller than I got the impression it would be from photos. A good thing, in my view.
At RTMC, I picked up a Televue NP101is used. It fits perfectly on the Super Polaris' stock saddle, though I had to put a couple of washers between the saddle and rings to get a tight seat.
But it looks like it belongs there. And that Super Polaris looks so new, it looks like a plausible factory package, even though the mount is 20 years older than the OTA!
-Tim.
|
rjsc2000
sage
Reged: 09/21/06
Loc: Portugal
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3136161 - 05/30/09 04:46 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Don't forget the pics 
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: rjsc2000]
#3136389 - 05/30/09 07:35 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I promise!
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3138726 - 05/31/09 11:01 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Okay, I took pics, but you'll have to wait until I get upstairs where I can use my Mac to resize the frames for posting.
The conversion was very simple to do. Absolutely no modifications to the Super Polaris mount were needed whatsoever. Only the covers on the Gotonovoa motors needed modification. Basically, a little clearance for the RA circle was needed on the RA cover, and the Dec cover needed material cut away to go around the SP's dec motor bracket (which I had to borrow from my other mount, as these mounts don't have the cast on mounting bracket on the saddle like some later ones, but one was provided with my original Skysensor kit. I'll have to find another one if I'm going to put the Skysensor back on my other mount.
Steve, I think you said that some clearancing for the RA or Dec gear needed to be made on the mount with a Dremel? I found that if I turned the gears around, such that the setscrew was on the inside rather than the outside (the way it's mounted on the motors), then no clearancing was necessary.
I still need to set the gear mesh and grease the gears, though, as I got an error message when I turned the system on (but I wonder if that might be due to my battery being low? I haven't charged it in months).
The Maroon Layer saw me setting up, so it socked in almost immediately. I'll try making adjustments tomorrow night after work.
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3138807 - 05/31/09 11:41 PM Attachment (206 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Okay, here it is, with my "new" TV NP101is ("is (not was)") mounted on it:
-Tim.
Edited by tim53 (06/01/09 01:09 PM)
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3138811 - 05/31/09 11:42 PM Attachment (171 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Pic too
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3138815 - 05/31/09 11:43 PM Attachment (154 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
This is also a pic
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3146505 - 06/04/09 11:08 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I've spoken too soon, it seems.
The system is nice to look at, but it doesn't work. I get an error message when I start it up saying that the RA motor is showing an over current, and I should check the balance.
RA balance is fine, so I disconnected the motor from the spur gear on the worm, and I still get the warning message.
Anyone else have this problem?
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3164030 - 06/15/09 02:22 PM Attachment (104 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Update:
Sent the unit back, but Steve couldn't find anything wrong with it. Got it back from Steve last week, and tried it again, off the mount to see if my problem repeated. It did, but when I turned it off but left it plugged in (red LED lit), and tried again an hour later, it worked fine!
So, I took it down to my basement shop where the problem first showed up, and it worked there, too.
So, I put it all back together, this time on a Quickset Hercules tripod I'd bought many years ago (for a mere $40!) and mounted on a dolly I'd made that just fits through my basement doorway (allowing me to leave a scope on the mount and wheel it around).
Tried it outside last night, because it was clear for the first time in a long time. Although I'm still getting myself familiar with the iOptron manual (which seems to be kinda sparse on some things), the unit worked rather well.
And the NP101is was quite comfortable on the Super Polaris with that tripod. Very sturdy.
It looks like it's going to be cloudy again for a while, otherwise I'd try polar aligning well and using Astro IIDC to measure the PE of the mount.
All told, I think I've got a good light-duty AP mount here for a total investment of:
$75 - mint used Super Polaris mount (craigslist)
$40 - used Quickset Hercules tripod (Pasadena Swap Meet several years ago)
$30 - used Vixen pier extension (RTMC a couple years ago)
$430 - new iOptron Gotonova goto upgrade kit (not supposed to be for Super Polaris, but fits with only modifications to the plastic motor covers, not the mount).
$575 - Total.
Not bad for a Vixen smooth PE (I haven't measured it, but expect it will be 20 arc seconds or better, and very smooth) with modern goto.
-Tim
|
pollux
artiste
Reged: 04/01/04
Loc: Burnaby Canada
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3164943 - 06/15/09 11:14 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
That's cheap (the total cost I mean)
I am thinking about adding GOTO to my GPD2 and I am looking forward for more report on that GOTONOVA.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: pollux]
#3165475 - 06/16/09 09:58 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
If it clears up again around here, I'll put it through it's paces!
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3168384 - 06/17/09 06:35 PM Attachment (97 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Well, this is disturbing. I think I did this right, but I'm going to have to rig up the old SP and make sure I measured the PE the same way I did the "newer" one. And that I'm doing this right.
I used Astro IIDC to measure the drift, in pixels, in RA and DEC. Interestingly, the dec drift was only 18 pixels over 20 minutes, showing that I was reasonably polar aligned (but not awesomely so). The RA drift over two full rotations of the worm was worse - about 34 pixels - suggesting that the drive rate was off sidereal by that amount (though I'm not certain it was running fast or slow, another thing to check!)
Here're my stats:
Scope focal length - 545mm (101mm f/5.4)
Point Grey Research "Flea2" pixels - 4.65 microns
arc seconds/pixel - 1.76
I plotted the data using Kaleidagraph and "normalized" the RA drift so that it ended at the same value it started with. Attached are the results. If I did this right, this mount has a pretty smooth PE of plus or minus ~20 arcseconds, or a total PE of ~40 arcseconds. This seems pretty bad for a Vixen mount, to me.
But I'll have to go back and use the same scope on the old Super Polaris and make sure I measure the PE the same way and with the same camera. Because I remember it being around 20-22 arcseconds, and I THINK that was total PE I recorded, but it might not have been (it was about 3 or 4 years ago I measured it).
If the old one's really twice as good as the "new" one, I think I'll keep the old one! But could there be that much variation in Vixen mounts?
I also seem to remember a friend of mine telling me he had a SP mount with only 5 arcseconds of PE, which would be pretty awesome even if he meant plus or minus (comparable to my Tak EM-10, in fact).
Not sure what to believe! Other vixen owners (any of their mounts) ever measure the PE on their drives? I'd be interested in hearing what you found.
-Tim.
Edited by tim53 (06/17/09 06:36 PM)
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3168419 - 06/17/09 06:52 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I may be wrong about the smoothness. Since my pixels were pretty large and exposures were 1" duration (on Regulus), the little wiggles in the curve must be due to the spur gears (the bigger wiggles seem periodic, and appear to have matches in the second rotation of the worm).
Hm...
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3171378 - 06/19/09 11:36 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I thought I was going to measure the PE on the other SP mount last night, but I got lazy and set up the 6" f/10 Newt on the EM-10 instead.
While imaging Saturn with it, I noticed that the planet drifted around far less than it did when imaging with the same camera and about the same image scale as I did the other night. It drifted over time in Dec (too lazy to do a rocket surgery level polar alignment), but in RA it didn't drift even a saturn disk-width, and the other night with the Super Polaris it clearly drifted more than a Saturn disk-width.
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3209699 - 07/10/09 10:20 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Just an update for others contemplating a similar upgrade.
I've been using this rig several evenings since I set it up to test the drives, and I would have to say that I really like the system.
For quick setup and alignment, it can't be beat! I can usually get polar aligned with the polar scope well enough to not need to make any dec corrections in long periods of high magnification planetary viewing with the TV NP101is.
Go to's are very good as well. You may have noticed I *still* haven't put a finder on the TV, but so far I haven't really needed it (I will add one, though).
One thing I like about the hand controller is that the light turns itself off after it's been unused for a period of time (dont' know how long that is). All you have to do is hit the enter button to bring it back on, though.
It has a multi-line LCD display, so there's none of that frustration of waiting for text to scroll across the screen to see what you're pointing at or what button the software wants you to hit next.
In short, I highly recommend the Gotonova upgrade to breathe new life into these old, high-quality mounts.
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3276674 - 08/16/09 09:47 PM Attachment (159 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I've been asked about posting pics showing details of the installation, so here they are...
Also, if you saw my posts on about the Mt Pinos trip this weekend, you'll see I had more problems with the gotonova not coming on, but found from Chris Ericson on the ioptron yahoo group that it was due to the power supplies I was using and that I had two scopes and my laptop drawing battery power from my van. When I got home and plugged the unit back into my usual wall outlet, it worked fine.
This first pic is looking down on the dec motor mounting bracket, and shows how I put a washer under the ioptron mounting bolt so that it would bear against the bracket, which is an open frame thingy that came with my original Skysensor for the other Super Polaris mount. In addition to this bolt, there are the four set screws on either side of the bracket that bear against the dovetail on the motor body. You can see in the photo that there's a gap at the bottom of the picture that shows that two of the set screws don't touch the motor housing because the dovetail is shorter than the Vixen motor dovetails. But the other two setscrews at the top and the bolt hold it nice and tight.
The motor covers are on in these pics. I could take them off if jpeople want to see the installation without them, but it's pretty straightforward. And this way, you can see where I cut away the motor cover to clear the Vixen parts. The most cutting away was right here, to make room for the Vixen bracket that supports the motor dovetail.
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3276688 - 08/16/09 09:54 PM Attachment (137 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
This next pic is just of the dec spur gears, visible through the opening in the motor cover. I show this because I was told that I'd need to use a dremel tool to provide clearance for the spur gears on both the RA and DEC. The kit comes with the spur gears on the motor shafts with the boss for the setscrew on the outside of the shaft. If you were to mate up the gear that goes onto the mount's dec worm shaft with the setscrew on the inside, you probably would need to grind some clearance in the mount.
For both axes, I turned the spur gears around on their shafts, so I needed no modifications to the mount at all.
-Tim.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3276706 - 08/16/09 10:03 PM Attachment (142 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
The RA mounting gave me a little more concern. The iOptron kit comes with a long bolt that runs through the RA casting and threads into the RA motor housing in installations on mounts like the CG5 clones and GP mounts that iOptron says the kit is designed for. But the Super Polaris doesn't have a hole through the RA axis in the appropriate location.
Add to that the fact that only two of the four set screws in the super polaris mount bear against the dovetail on the iOptron motor housing, I thought it would get jarred loose pretty easily.
But in practice, I haven't found this to be a problem at all. Recently, when I took the mount to Utah with me, I did find the RA spur gear backlash was pretty loose, so I quickly adjusted it and retightened one of the setscrews with an allen wrench (the screws are accessible with the motor covers on, so this is a quick adjustment).
This pic just shows the motor and cover closeup, with the spur gears visible in the gap in the housing on the side.
Here is where most of the motor cover cutaway needed to be done - to clear the RA setting circle. I used a coping saw for the big cuts on the DEC cover and a half round file for the RA cover, and general cleaning up of the cutaway surfaces when I was done.
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3276712 - 08/16/09 10:07 PM Attachment (122 downloads)
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
This last pic is probably too dark to show what I'm trying to show, which is that the setscrews are accessible without taking the motor cover off, if you find yourself needing to adjust the backlash in the spur gears or just tighten the RA motor assembly at some point.
The setscrews are in that shadow right above the lattitude scale... trust me! 
|
tim53
Postmaster
Reged: 12/17/04
Loc: Highland Park, CA
|
Re: Goto'ing a Super Polaris mount
[Re: tim53]
#3276716 - 08/16/09 10:10 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
One additional remark:
You may have noticed that the clutch handle for the RA is pretty close to the motor cover in the locked position. I actually had to reposition at least the RA clutch lever on its spline to clear the motor cover and still tighten properly. But it was easy to do - just remove that philips screw, rotate the handle on the spline and put the screw back.
-Tim.
|
Previous
Index
Next
Threaded
