Stepper Drive Conversion

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I am making every attempt to fabricate using a drill press and hand tools only.  This will require a bit of scrounging from time to time, but the hard parts to make are off the shelf or slightly modified items easily obtainable from a variety of sources.

Here's a teaser.....

Shown in this image is the Hand Paddle (small box with the red buttons) and the Stepper interface box.  A laptop or deskbound computer are needed to run the electronics.  Any DOS machine 486-50 or faster is fine. 

Here is a short low res MPEG of the DEC drive in action.

2/1/03  I have completed the electronics and have done the basic tuning of the stepper drive.  Kudos to Lenord Stage at for all his input during the tuning process.  I have taken copious notes and will offer up my version of the tuning process.  I am currently waiting for one elusive piece of hardware and the mechanical portion will be complete and  ready to star test.

2/5/03  First light with the new drive!! Pointing was quite good, despite my pushing incorrect buttons on occasion.  Tracking needs to be tweaked a bit, it is running a wee bit slow.

3/28/03  "Second" & "third" light with the drive, out in the field this time.  Friday 3/28 I headed out to AZ City for the All AZ Messier Marathon, not as a combatant, but just to get out to  some darker skies than my driveway.  If for some reason the drive didn't work I figured I could "attach myself" to one of the other scope owners and get some viewing in, VBG!  I got a real decent polar alignment and did the Reset Equatorial, which is similar to the One Star alignment of the Magellan II.  Alignment consists of getting the wedge set, pointing the scope accurately at a star, telling the software what star it is and hitting the R key on the keyboard.  That's it!! No point at 90 degrees DEC, then pointing at two stars.

4/05/03  "Fourth" light as it were.  At this point I have deemed the drive completed other than minor tuning.  I took the scope out to Whispering Ranch where I have on of my permanent piers planted.  Scope worked perfectly!!  Pointing is incredibly accurate without the hassles of an involved electronic alignment.  For those of you who have asked, you can un-clutch the drive and re-sync on an object when you arrive at your destination.  Doing this does not affect local pointing accuracy but it has some effect on long slew accuracy.

4/18/03  I am in the final stages of putting together a parts and instruction list.  I will make these available for a modest contribution (around $25 US) to cover the time it took to design this thing and find all the parts.  You won't believe the stack of catalogs from mechanical component companies I have, it's over 3' (that's around 1 meter for those of you over the lake form us) high!!  

11/9/03 Progress is continuing on the drive project.  Lack of updates has been due entirely to my attempts at noise reduction in the RA drive.  I am reluctant to publish a parts list or instructions until I have solved this annoying issue.  To those of you who have contacted me, please be patient as I will eventually make the information available once the noise issue has been dealt with and testing is complete.  FWIW, the drive performs excellently and tracking and pointing is incredible.  We found and tracked Pluto in late May with the Bartels drive, the planet stayed centered in the FOV for an hour at the high power we were using.  The scope was set at f/10 and we used a Meade 6.7mm UWA for a power of 380X.  Surprisingly the majority of the noise comes from the stepper/gearbox assembly where it is attached to the scope and NOT from the driveshaft.  Details to follow...

11/23/03  I think my quest to quiet the stepper drive has been successful. A new drive mechanism using a toothed belt and gears for same has been designed, redesigned 4 times and tested at least as many!  A thorough test last night proved the drive is darned quiet and an all-nighter or two will follow this weekend, weather permitting.

12/20/04  The final version of the DEC and RA drives is nearing completion! A number of people have inquired about information to do their own conversions.  I will put together a CD with all the information on parts sourcing and construction details.  The disk should run about $30.00 US.

Copyright 1997-2012by Bill VanOrden