Thursday, November 03, 2016

Back Again

It has been a long time since I have posted here. Sorry but life has had other things for me to do. However, I have been playing around with Arduino microcontrollers for a while and have just found a new application.

With the All American Solar Eclipse coming next August 21st, I have started thinking about filming it and have also been interested in filming other astral phenomena so I figure building a polar axis tracker for my camera and telescope needs might be interesting.

I found a design for a DIY Polar Axis Tracker based on the Barn Door design and started looking into the math used to determine how to drive it and the hardware. I was in Portland Oregon this passed Summer and was directed to Surplus Gizmos by my son. They have all kinds of electronic, electric and mechanical hardware for sale.

I was able to get a couple of stepper motors (which may or may not work), a lead screw with an 0.1 inch pitch and a 3/8 inch diameter. These were my first pieces of hardware for the device.

Let me drop back a little and describe the device. A Barn Door Tracker is essentially two pieces of wood with a hinge connecting them. The hinge allows the two parts to swing through an angle as a barn door might when it is opened with respect to the door frame. By anchoring one side of the door to a tripod as a “ground” plane and then moving the other side at a controlled rate, the moving side will remain relatively fixed from a cosmic standpoint as the other side moves through an arc as the earth turns below it.


So the trick is to make the “door” open at a rate consistent with the rotation of the earth (360 degrees in 23.9344696 hours). I will be posting the steps I go through here to make this thing work so stay tuned.

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