The theory behind a barn door tracker is to mount a camera on two hinged pieces of wood and increase the angle between the pieces of wood such that the camera lens tracks the movement of the earth.
Parts Required (Essential)
2 Pieces of wood minimum 32cm long, wide enough (and strong enough) to support your camera.
In these instructions, two off cuts of skirting board were used.
A M6 bolt and captive round nut ....DON'T be tempted to use any old bolt.....the thread size IS important.
A brass hinge (or two hinges in this case)
1/4" to 3/8" Convert Screw Adapter for Tripod
Pro 1/4"-20 Tripod Screw to Flash HotShoe Mount Adapter
2 wood screws
A rubber band
Some Araldite (or similar)
Parts Required (Optional)
Telescope finder scope
Plastic pipe clips
An old watch face with second hand
A Ball-Joint Camera Mount
Join the two pieces of wood with a hinge or hinges as shown in the image below
Attach a lever (in this case an old “IKEA” spanner) to the M6 bolt
Drill a hole through the top piece of wood to allow the M6 bolt to fit through, but hold an M6 nut securely.
The distance between hinge and hole centre should be 29.5cm
Araldite the bolt into the hole. If you have a spare M6 bolt apply a bit of grease to the thread and leave it in the M6 nut while the araldite dries. This is just in case any of the glue clogs the threads
Seen from below
Once the glue has hardened completely, insert your bolt + lever and attach the captive nut.
To attach the tracker to a tripod, we need to insert a 1/4" to 3/8" Convert Screw Adapter into the base of the tracker.
Position it near the hinge end of the tracker starting with a drilled hole smaller than the adaptor and then screw it in tight to the wood. Loosen off, apply a bit of araldite to the threads and screw back in.
Alllow the araldite to dry. (again you should think about protecting the inner thread when using glue)
Directly above this cut out a small square recess to accept
the Pro 1/4"-20 Tripod Screw to Flash HotShoe Mount Adapter.
Drill a hole through the recess to allow the threaded part of the adaptor to go right through
Secure this with the locking nut provided with the adaptor.
Insert a wood screw centred at the end of each piece of wood and attach a rubber band to give resistance against the movement of the bolt.
Now you could finish there, but there are some extra parts need to allow this to work.
To get your camera in the correct angle, you’ll need a ball-joint camera mount.
I used a model by BENRO
This has a quick release mount and allows the camera to pretty much be positioned where you want it.
Really worth considering especially if you are mounting an expensive camera !!
Secondly, when aligning the tracker you need to point the hinge at the pole star.
To help with this, a cheap finder scope is ideal.
Here it is mounted using a couple of pipe clips.
All that is left is to mount the adaptor on a tripod and align the hinge with the pole star.
When you align, the lever bolt is to your right and the hinge is to your left looking North.
THE FINISHED ARTICLE
In use, you will need a watch with a second hand.
Try and rotate the lever at the same rate as the watch i.e. One revolution per minute. (the reason for the M6 bolt thread size !)
You can leave the movement alone for up to 10 seconds without getting any "trails" so you don't need to be too precise.
Astro Boot (for finder scope)…..you’ll have to shop around !
ebay ( for 1/4" to 3/8" Convert Screw Adapter for Tripod)
ebay ( for Pro 1/4"-20 Tripod Screw to Flash HotShoe Mount Adapter)
Park Cameras ( for BENRO mount) or similar