If you want to do astrophotography, a star tracker is a must. Sadly, they’re far from being cheap, which is an obstacle for many of us. Thankfully, there are folks like Nico Carver of Nebula Photos who teach us how to make a DIY star tracker for only $30. In this video, he guides you all the way through making and using a simple barn door tracker: from the parts you need to the finished images you get with it.
Nico’s design is adapted from George Haig’s barn door described in Sky & Telescope magazine in April 1975.
You will need
For starters, here’s what you’ll need:
- 2x 1×6 boards cut to 12.6875” (322 mm)
- 2x 1/4” 20 Tee Nuts
- 1x 6” piano hinge or  3” door hinges
- 6x small wood screws
- 1x 4” or 3” long 1/4” 20 Carriage Bolt with round head
- 1x 1.5” long 1/4” 20 bolt
- 1x 1” long 1/4” 20 bolt with socket head cap
- 1x blank CD (or just use an old one)
- 1x Printer paper or Avery CD Label (8692)
- 2x 1/4” 20 nuts
- 1x 1/4” washer
- 1x 3.5” metal brace for the handle
- 1x ball head
- 1x metal drinking straw or finder scope
- Some tape
- Epoxy or super glue
- 2x Screw eyes, #6
- 1x rubber band
Using math, Nico calculated that you should move the two boards one away from the other at 0.25 degrees per minute to keep up with the stars. The hole for the bolt, in this case, should be 290mm (11.4”) away from the hinge. If we track at one rotation per minute we’re going to get perfect, round stars without trailing. But since math gives me headache, I won’t even try to explain. Nico does it really well in the video so I don’t have to. :)
Nico uses a simple metal drinking straw for polar alignment. He tapes it on the side of his build but admits that it’s not a perfect solution. Still, it allowed him to take 2-minute single exposures and end up with some neat shots.
How to make
Start by cutting two pieces of 1×6 board to 12.7” (322mm). If you don’t have a saw or you’re as clumsy as I am, nice guys at Home Depot will cut it for you.
Next, mark and drill holes for the hinge and then screw it on. You can use one 6” hinge, but two smaller ones will work as well.
Drill a 1/4” hole exactly 290mm from the hinge and attach a 1/4” 20 nut. Add some glue to secure it, and hammer it in. Repeat this step, but put the tee nut in the middle of the bottom board – that one is for attaching your tripod.
Now screw in a long carriage 1/4” 20 bolt into the first hole.
Print and attach a pattern onto a blank CD. Alternatively, print it out on regular paper, cut it out, and glue it onto any old CD you have lying around.
Next, attach the clock wheel and a handle permanently to the bottom of the drive bolt. You can use some bolts, washers and a bit of epoxy and make sure that it’s attached well to the bottom of the drive bolt.
Attach the ball head to the top board. Drill a hole and attach the ball head using a shorter 1/4” 20 bolt.
Now attach the screw eyes and the rubber band on the side of the board. You will look through these as you rotate the wheel.
Finally, attach your polar alignment device and align it with the hinge.
How to use
It’s shooting time! Polar align your build first by centering the Polaris with your straw (or whatever you choose to use as a polar alignment tool). Then find the object you want to shoot and set up your camera.
Of course, focus on the stars to make them pin sharp. it’s best to use the Live View and zoom all the way in so you’ll see what you’re doing. Put the camera to Bulb mode and use a remote shutter to start and end your exposure.
Nico used a Canon 1500D and a Rokinon 24mm lens. With this lens, he learned that he needed to move the wheel counterclockwise 15 degrees every 2.5 seconds, so it’s something to keep in mind. He made a couple of 2-minute exposures and stacked a few of them together. But even without stacking, you’ll see that the raw images are super-sharp and that there are no star trails. In the video, you can see the final image, and I’m amazed at how much you can achieve with a fully DIY approach.
Nico points out some of this DIY tracker as well. First of all, it can be uncomfortable on your neck to look down at the wheel as you rotate it. Also, for some people, it can be boring to manually rotate the wheel for a long time. But if you’ve got good company or some good music or podcast with you, I think you’ll be fine. And lastly, as already mentioned, the straw isn’t the ideal solution for polar alignment, but this is something he plans to work on. And I personally look forward to seeing what he’ll come up with.
Personally, I found this video very useful as I got very interested in astrophotography. It’s a very expensive hobby, so there are a bunch of obstacles ahead of me. But this is something I’m definitely going to make and I’m already looking forward to it.