Cheap astrophotography dreams

[johnridley]

With the unexpected (by me) success of the Canon Digital Rebel in taking wide field astrophotos at relatively long shutter speeds (several minutes), I'm thinking it's time to build a tracking platform for the camera. Typically this has meant a "barn door" tracker. I may just go with that, but one of the problems with a barn door tracker is that it does have some tracking error because it's not a true tangential mount.

I have been toying with the idea of using a microcontroller to drive the steppers, and then I could vary the speed as needed to eliminate any tracking error.

However, it also occurs to me that it shouldn't be that hard to do a true tangential drive with a plywood circle segment. I've seen things on the web of people who have made worm drive gears by applying J.B.Weld to the edge of a wood circle and imprinting a threaded rod onto it.

I will probably still use the microcontroller to drive the stepper motor, because it's just easier and less parts, plus I'll be able to microstep using PWM. But I think I'll just try to build the damn thing first and worry about fancy drive systems later, otherwise I'll never get it done.

I'd like to have this done for the Perseid meteor showers later this month.

Comments

[ex-erikvolso370.livejournal.com]

The cool thing is how the tracking blur in the Cygnus shot lines up just so to make Brocchi's Cluster (The Coathanger) really jump out. Well, that, and the way you could take a 80 sec exposure at 3200 and get no sky glow on the horizon.

Cool!

[johnridley.livejournal.com]

I hadn't even noticed that. Pretty cool, it makes it into one object! Oh well, I'll still take "sharp" over "interestingly blurred" any day. Off to Lowes for parts...