Saturday, March 28, 2015

more barn door tests (Richmond Hill)

"Second light" for the barn door tracker. So to get more data and experience. I also wanted people to see it in action. Another objective was to gauge portability. I hauled it about the subway.

Made all kinds of mistakes. Again!

Set up beside Nicole inside The Ellipse of the David Dunlap Observatory. Near Chris V. Chatted with various members, including Peter, Shawn, Iosif, Allard, Chris J.

Like Tuesday, Mamiya tripod with the Manfrotto hex adapter. Custom barn door tracker and control unit (and 9v battery)! Sirui ball head with Arca-style plate. Polar alignment with Celestron finder scope. Mounted the 40D and 18-55 kit lens. Zoomed out. Already on Custom Settings 1. Attached the intervalometer. Bulb mode.

9:34. Took first test shot. Manually focused on Sirius.

9:39. Oh yeah, the bottom knob. Pivoted the base of the ball head. Ha. I was able to get a good angle this time. First good shot.

30 seconds, f/7.1, ISO 1600. Lens at 55mm. OK. Changed the camera settings. Ready for long exposures.

9:40. Oops. Forgot to turn on the drive!

180 seconds, f/8.0, ISO 100. Duh. Turned on the motor. There's was a bit of slop in the mount. Tightened the tracker on the tripod hex plate.

180 seconds, f/8.0, ISO 100. Jitter. Huh? Turned off the drive to investigate. Oops. Discovered the bent rod was touching one of the tripod knobs. Stiff rods? Stiff knobs? Oh my. 

Did a few more test shots. Forgot to turn the drive on. Again! Tried once more. Sped up the drive slightly. Camera shutdown. Battery issue again! Gah. I suddenly realised I had forgotten to install the battery grip! Put in another battery. No response. Damn. Already too cold. -6°C Nicole had predicted. Put the remaining batteries in my pants pockets.

10:15. Reframed.

180 seconds, f/8.0, ISO 100. Still slightly streaked. We all thought the focus off a bit? Steve loaned me his little Kendrick Bahtinov. Suddenly realised I had not brought my Y-mask. Huh. If I'm not bringing a computer (to pack light) I better bring at least the mask...

180 seconds, f/8.0, ISO 100. Better! Better focus. Still trailing. Maybe I need to re-evaluate the polar alignment. Oh. Quite far off. Adjusted, i.e. centred.

180 seconds, f/8.0, ISO 100. Damn plane. Hey! Longer trails. OK. Polar alignment is becoming a factor. Will need to research this...

Lessons learned:
  • Don't forget to turn it on. That's why I put the red LED in it! 
  • Use a focusing mask. Or focusing software.
  • Examine first test shots for focus.
  • Pivot the ball head. Turn it to get the notch in the right spot.
  • Don't forget to warm batteries.
  • Don't forget to attach the battery grip. 
  • At long focal lengths and long exposures, will need better polar alignment. 
  • And don't forget to turn it on.
Fun. Quick pack-up.

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