Tuesday, September 27, 2016

tested in the field (Blue Mountains)

Conducted a test of the custom Canon mirror lock-up cable (based on the Beskeen design) with the special version of Backyard EOS. In the field this time (versus the bench), with the NexStar 11, on a double star. Everything worked rather well.

I was able to shoot very fast exposures, which will be necessary with some bright stars, and have the mirror up in advance of the shutter opening, in an effort to reduce or eliminate vibration. And, at the end of the imaging runs, I was happy to see the open-shutter command cleared, and everything, the camera, the software, working normally. While the seeing was very poor, I was happy with the results overall.

δ (delta) Persei. All shot with: NexStar 11 GPS at f/11, Canon 40D, Backyard EOS, mirror lock cable, USB control cable, ISO 1600, daylight white balance. North at the top-left; east to the bottom-left.

delta Persei at 15 seconds

15 seconds. Many field stars visible. δ Per B visible.

delta Persei at 1 second

1 second.

delta Persei at 0.5 second


delta Persei at 0.25 second


delta Persei at 1/8th of a second

1/8th of a second.

delta Persei at 1/15th of a second


delta Persei at 1/30th of a second


delta Persei at 1/60th of a second

1/60th. Pretty blobby. Bad seeing? No C star.


The yellow LED is awfully bright. Perhaps, if I do this again, I'll use an orange.


I was a little surprised at the end result. There still seems to be some vibration. Unless it was very bad seeing. Next test will be to shoot video on a tight double star.


It had not occurred to me before that if I want to use this mirror cable in the future, say in the backyard, there may be a technical issue. It is built using COM serial tech and needs a USB-serial adapter. And, of course, I'm using this same old tech to drive the mount. I was lucky to be able to borrow the other unit from the CAO. Hmm. I will need to figure out a solution.

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