The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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i know this might sound stupid but how do you get your latitude?
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Look it up on a world map, GPS, Google latitude US cities.
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Ed Jones
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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thanks i got it
doc
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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The bear
scholastic sledgehammer
Reged: 02/11/08
Posts: 824
Loc: rushville, indiana
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when you use the ac motors then you use a battery pack when you are in the field could you post or send me how you hooked all this up as i am a little electronics challenged and trying to configure al this stuuf so i know what to get when i build my scope(s)?
doc
you are great for helping us out with this soon we will all have eq mounts.
  
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Longitude -85.42786 Latitude 39.59153
"current build 6 inch F6.5 "Little Toe"
"if all else fails use duct tape "works for me"
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Bear,
Here is a shot of my 8 inch on the finished platform, you just plug the motors into a DC to AC converter (about $20) which plugs into a car battery or power pack. I was able to try it out last night but it was almost a disaster. I wired up the motors, plugged it in and the left motor didn't run! Of course it was the motor I hadn't previously tested and now these motors are no longer available. Fortunately these motors can be taken apart so I took the motor off the gear box and freed up the motor shaft. I put it back together and it worked fine.  I took it outside and put my 8 inch on it (my 12 inch will be a bit heavier). I plugged it in to my extension cord, focused on a star and watched for drift. The star drifted right across the field. #&@!! Man this thing doesn't work at all, then I chased down the other end of the extension cord and sure enough the wife had unplugged it. With the motors running the stars were rock steady, slowly drifting north or south. I had only roughly pointed it north, later I will make a laser holder to do this more precisely. It looks like it works as designed and the shafts don't need to be knurled. 
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 662
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that is a cool scope i like the wood is it maple ?
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Yes, all maple except the octagonal bottom tube which is Baltic birch.
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Ed Jones
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JasonNB
member
Reged: 11/21/06
Posts: 98
Loc: Spring Hill, TN
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Subscribing to thread.
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Zhumell 8" Dob
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RedIrocZ-28
Pooh-Bah
Reged: 09/18/05
Posts: 1175
Loc: Grand Rapids, Michigan
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Ed, seems there is a problem with the link to the motor drive circuitry you posted. It goes to the archives and then has an error when you click the link to go to the archives.
Can you give the name of the post that the info is in? I would like to look this up because I need to get my EQ table back working after the DC motor control circuitry burned out last week...
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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I've never post a DC motor control, AC yes but not DC. 
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Ed Jones
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RedIrocZ-28
Pooh-Bah
Reged: 09/18/05
Posts: 1175
Loc: Grand Rapids, Michigan
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Ed, I had a DC motor on my platform, that worked "ok". I was able to track Mars for 4 minutes but not much beyond that. I was then tweaking the gearing and during testing the damn hand controller burned up a resistor. So, I decided to switch to either AC or Stepper motors. And I noticed that you were using AC. So I'd like to see whats the story on your design 
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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My link doesn't have the post number either, looks like CN has dumped it or something. Too bad that speed control post was pretty neat. Maybe Mike can help, it was called "How to make a cheap speed control". If not I still have the pictures I took, basically all I did was replace one or two resistors and wire in one in series and one parallel with push buttons in a commercial inverter. If CN can't help should I post it again?
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Ed Jones
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stardustborn
member
Reged: 11/30/07
Posts: 54
Loc: LI, New York
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For those who want to get started down the road, TL Systems sells a kit for an eq platform with stepper and controller. I made the kit and it worked fine for my xt10 but I then canabalized it for my current mount. The kit rollers,parts and such may be minimal but at least you get the motor, controller and basic idea. I found it confusing and frustrating trying to get my mind around the whole thing and finding parts to make my own so the kit worked well for me.
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Orion xt10i on an ugly homemade english fork eq mount
A stepper motor,wires and stuff
Push to digital circles(COL) into "The Sky"
"The Noble Turkey Observatory".... (a small shed)
http://picasaweb.google.com/stardustborn/NobleTurkeyObservatory
Orion Starblast 4.5 imaging scope
Meade DSI 2 pro mono
...and a piece of space to peer into
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RedIrocZ-28
Pooh-Bah
Reged: 09/18/05
Posts: 1175
Loc: Grand Rapids, Michigan
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Ed, found the link
http://www.cloudynights.com/ubbarchive/showflat.php/Cat/0/Number/2062609/page/0/view/collapsed/sb/5/o/all/fpart/1/vc/1
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Great! I see that Jensen still makes a 180 inverter but it's a different case color. Maybe it's the same board inside. You can get one for about $22.
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Ed Jones
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arpruss
scholastic sledgehammer
Reged: 05/23/08
Posts: 855
Loc: Waco, TX
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Two questions:
1. What would happen if you took one of the motors out of the design? Would there be more slippage? Or would a single motor not handle the weight?
2. Would you be able to post a photo of the whole underside of the top board? I am kind of confused what the three bearings at the back bear on. Thanks!
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Coulter Odyssey 13.1" split-tube
Coulter Odyssey 8"
Home-made 7.8" F/4 dobsonian travel scope
Home-made 68mm F/5.3 achro (typically used as finder on 13.1")
Skymaster 15x70
BPTs4 8x30
32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow
Palm TX with AstroInfo and RescoViewer
Edited by arpruss (10/29/09 08:41 AM)
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Initially I used only one motor but I often use other scopes with different COGs. One scope is top heavy and the motor would slip on one side because there was little weight on it, 2 motors fixed that problem and heck they are only $19. If you only use the scope it was designed for then you can use 1 motor. If you use 2 motors I found that you can wire them in series to use even less current and they still work fine.
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Ed Jones
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arpruss
scholastic sledgehammer
Reged: 05/23/08
Posts: 855
Loc: Waco, TX
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Quote:
Initially I used only one motor but I often use other scopes with different COGs. One scope is top heavy and the motor would slip on one side because there was little weight on it, 2 motors fixed that problem and heck they are only $19. If you only use the scope it was designed for then you can use 1 motor. If you use 2 motors I found that you can wire them in series to use even less current and they still work fine.
Makes sense. I will be designing for my 13" with ~25" high center of mass, so this may well come up.
If you do have a photo of the whole underside of the top board, that would be appreciated. I am guessing that you have a smaller beveled sector at the south end?
Is there anything useful here that could be done with the steppers and gears from a dead Roomba?
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Coulter Odyssey 13.1" split-tube
Coulter Odyssey 8"
Home-made 7.8" F/4 dobsonian travel scope
Home-made 68mm F/5.3 achro (typically used as finder on 13.1")
Skymaster 15x70
BPTs4 8x30
32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow
Palm TX with AstroInfo and RescoViewer
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Here is the bottom side of the top board. The north bearing is parallel to the ground, the south bearing has a 15 degree tilt I think to it to keep always against the ball bearings. Note the stick on the north bearing to stop the platform at the end of travel, the smooth shaft can't climb it so it stops. I just push it back to reset, I doubt if any other platform is this easy to reset.
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Ed Jones
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arpruss
scholastic sledgehammer
Reged: 05/23/08
Posts: 855
Loc: Waco, TX
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Nice!
Do the 1/15 rpm motors have any speed adjustment options?
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Coulter Odyssey 13.1" split-tube
Coulter Odyssey 8"
Home-made 7.8" F/4 dobsonian travel scope
Home-made 68mm F/5.3 achro (typically used as finder on 13.1")
Skymaster 15x70
BPTs4 8x30
32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow
Palm TX with AstroInfo and RescoViewer
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