Cheapskate Astronomer Builds A Sky-Tracker from a 24 Hour Timer

A couple years ago I saw the IOptron Skytracker.  Choked on the price.  $400? Really?

OK, it's DC. It will work anywhere. That's cool.  It's got a lot of torque, and an angle-adjuster built right on to it.  Nice.

But $400?  Dang.

Being the Cheapskate Astronomer, it occurred to me that a 24 hour timer went around once each day. That should work, as long as it rotates in the right direction.

I got mine at Home Depot during Christmas time when they had it in the Christmas decoration section.  It was just under $5.

Now you have to plug these things in, so it won't work out away from electrical power.  That is the big downside of this plan.

Also at Home Depot, I find that a 1 1/4 inch PVC union fits right on the part that turns.  It is important to note that the quarter-size part in the center does not rotate.  Only the outer ring with all those gray thingys you pull up or push down turns.

So here's what I buy.

That's a 1 1/4 inch union, a same size cap, a 3/4 inch 1/4-20 hex head bolt, zinc coated, a couple of nuts and fender washers.  I ended up using only one of the fender washers and one of the nuts.

Drilled a hole in the center of the cap.

Installed the bolt, washer and nut.

Now, tricky part. Glue the PVC union on to the dial of the timer. Work slowly and carefully, getting it centered, but don't let ANY GLUE get on the part between the dial and the part that doesn't turn.  I used superglue.

And here's how it looks glued up.

To mount the thing to a tripod, I simply glued a piece of wood to the back, then used a clamp to clamp that to the head of a cheap $20 tripod.  The tripod head has pan and tilt on it, so I lined the pipe union up with the North Star.

Then get your camera all ready, and mounted on the cap on the 1/4-20 bolt. Looks like this:

Without a multi-angle mount (ball-joint) I can't aim the camera anywhere but at the celestial equator.

Also, the piece of wood I glued on to the back of the thing interfered with the extension cord, so I had to trim it with a Dremel tool to allow the extension cord plug to plug all the way into the back of the timer.

But it worked.  It bore the weight of this small camera, and rotated, keeping aimed at one part of the sky the whole time.

With a ball-joint mount, I'll be able to point the camera anywhere in the sky.

And with that Canon Powershot camera and CHDK, I can take up to 15 second exposures and a script for intervelometer features, and take long exposure images of one part of the sky all night long, or at least until the batteries in the camera are drained.  Use rechargeable Li-ion batteries and you get a couple hundred images at least.

Total cost is less than $10 for the sky-tracker.
I'm not the first to try this. Here's one http://www.instructables.com/id/Standalone-mount-for-astro-photography/

and here's another: http://www.hkastroforum.net/viewtopic.php?t=26221&sid=04811df9e261b1af3