AVR Barn Door Tracker for Astrophotography

zzjBarnDoorTracker

[ZigZagJoe's] first foray into astrophotography is this impressive AVR barn door tracker, which steps up his night sky photo game without emptying his bank account. If you’ve never heard of astrophotography, you should skim over its Wikipedia page and/or the subreddit. The idea is to capture images otherwise undetectable by the human eye through longer exposures. Unfortunately, the big ball of rock we all inhabit has a tendency to rotate, which means you need to move the camera to keep the night sky framed up.

Most trackers require precision parts and fabrication, which was out of [ZigZagJoe's] grasp. Instead, he found a solution with the Cloudbait Observatory model, which as best as we can tell looks vaguely similar to the tracker we featured last year. Unlike last year’s build—which uses an ATmega32u4 breakout board— [ZigZagJoe's] tracker uses an ATTiny85 for the brains, running a pre-configured table that determines step rate against time.

You’re probably asking “Where are the pictures?” It seems that [ZigZagJoe] has been plagued by clouds recently, but he promises they are forthcoming. Head over to his build thread on reddit for more details on the project’s design and hopefully future posts with some pictures. And swing by this site for a bunch of files on building your own.

16 thoughts on “AVR Barn Door Tracker for Astrophotography

    1. I’m actually kinda suprised HaD hasnt featured his Saver2 app. (Maybe the legality?) It allows the interception of Streamed music from multiple free music services, He even has an awesome Pandora player with it just go to his site they listed with just the main URL

      1. I think it’s more that HAD is a hardware hack site rather than software. Besides, it’d be embarrassing, haven’t really had the time or motivation to do much on saver2 lately… Soon(tm)

    1. A cloud detector with a thermopile would be the best idea, look for the direction the clouds are travelling, in offset the thermopile to look a few degrees behind the tracker target, when the temperature rises (clouds are warmer than clear skies), stop taking pictures, temperature drops, resume picture taking.

  1. Nice rig. I did the same thing, but my software was a lot simpler. It just ran the stepper at a consistent rate. The best thing is to take the tangent error into effect.

    New astronomical equipment is always plagued by clouds. The bigger/nicer the scope or the more work you put into it, the longer the clouds last.

    1. Yeah, that was my initial plan, to drive it at a constant rate, but at 250mm things went out of whack really quickly. So I ended up to figuring out the math, which really wasn’t all that bad in the end – just law of cosines and some brute force on the part of the calculator program. Both the AVR program and the calculator program are posted at the link in the OP.

  2. Like auto chicken coop doors I thought this somehow kept animals in nighttime confinement. How does an Alt-Az mount become a barn door?

    1. The Barn Door Tracker bit refers to the upper two boards – see http://en.wikipedia.org/wiki/Barn_door_tracker . Long story short is by driving the two boards apart, one can compensate for sidereal motion when polar aligned. The Alt-Az adjustments are for said alignment as I was planning on mounting it on a PVC stand which would of course have no adjustments.

  3. Old and venerable. Glad it’s still being taught and used. Anyone interested in this is welcome to join me for a night out with the stars. Great for raising a family.

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