Barn Door Tracker
I have long wanted to make what's called a barn door tracker so I could take photos of the night sky without the telescope. This is very nice for shots of the Milky Way (our own galaxy), for example. It always seemed very complicated. Well, a hand driven one can easily be assembled in a few hours and then you too can track Hale-Bopp with a camera! Exposures of up to 5 minutes can easily be done, and the results can be breathtaking, especially with telephoto lenses away from city lights.
Here is what the basic setup looks like. You turn the stick on the left at 1 rpm by hand. The stick is attached to a screw, which drives the plates apart.
It's important to be able to aim the camera where you want. Camera mounts cost $60 and up. I decided to make my own. The camera mount was about $5 (but this is actually half of the piece I bought, so I can now make another!)
Although with a little practice, you can track manually on the stars, it can be difficult to keep track of a watch and turn the stick at the same time. I find I am not good at counting off seconds. I also want to motorize my telescopes to track the stars, so I started with a relatively easy project: an electronic star tracker.
In place of the popsickle stick on the left (in the above image), you can place a stepper motor and sit back and watch an electronic timer circuit do the work! I used a stepper motor from a surplus shop to drive the screw. I think it came out of an old 5 1/4 floppy disk drive! It makes 100 steps per revolution (3.6 degrees per step), which should give good photos. I will post my image results this weekend.
Electronic have been quickly added by placing the breadboard of the circuit on the barndoor platform! The entire circuit cost less than $20 in parts. The stepper cost me $2.00. Eventually I will replace the breadboard with a better, more esthetic perf board, but this does work.
Two screw eyes could substitute for the finder scope seen just above the hinge. It's held to the board with my favorite adhesive: aquarium sealer (silicone RTV).
Here's a detailing of what everything is.
For more details on how to make the barn door tracker, click on Construction Photos.
Others have also made these camera and have more detail on some aspects. Here are some other very good links I found (some were found after making mine, so feel free to borrow their ideas):
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