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Old 8th December 2015
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Astro tracker revisited

Back in September I rabbited on about a astro tracker I had made, and hinted I was going to redesign it. The original item used a worm gear and drove the camera table from the shaft in the centre.

Well I started again, bough some miniature toothed belt and suitable pulley and now have a design that drives the camera table from the edge. This should reduce the mechanical backlash in the system.

So: here's one I just took. Orion's belt and sword.



It's quite a faff. I have to set the E-M5 to a high ISO to get an image bright enough to focus, then set it to ISO200 for a long exposure, and that is what I did for the shot above.

However it is easy to make a mistake in the heat of the moment (heat is the wrong word on a clear night in December) and expose 60 seconds at ISO 3200.

You just get a white rectangle. But ... if you pull it back far enough - look, it's full of stars!



This had the full dark frame subtraction so I figure these really are stars (about 60 degrees west of Orion) if anyone recognises a constellation in there.

75mm lens. Almost wide open. It covers a patch of sky the size of your fist at arms length*

Pete

*It wouldn't be more than arms length would it pete..
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Old 8th December 2015
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Re: Astro tracker revisited

Go on show us shots of your machine from lots of angles. I need something to work at in the shed on those cold dark nights after Christmas.

Shots looks good and you do not have to worry about noise!
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Old 8th December 2015
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Re: Astro tracker revisited

Well done Pete. Good stuff. Any problems with light pollution?
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Old 9th December 2015
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Re: Astro tracker revisited

They look really good Pete, nicely done. I'll second Ed's request for some images of the kit.
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Old 9th December 2015
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Re: Astro tracker revisited

Alas, light pollution is a very big problem here. I will have to make the gear more portable (make a batterypack) and go somewhere properly dark. I am amazed by the astro pictures you see on line and in magazines, because the results I get require a whole lot of enhancing to remove the pollution, improve the saturation and add punch. Harrumph.

I will get some pictures of the gear and put them in this thread in a couple of days :-)

Pete
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