Sunday, April 10, 2016

Messier Marathon Night Results

"Mission Accomplished!" to use a cliched phrase. "Goal Reached" might be a little better, or maybe "Dumbness Overcome."

This was one of my first attempts to use my DSLR in quite a while, and I managed to make a lot of mistakes early on:
  • Forgetting to return to ISO 1600 from the composing setting of 6400
  • Forgetting to set the shutter control to bulb
  • Forgetting to increase the number of frames on the DSLR controller from the dark frame to light frame counts
And so on. The evening began with starts and restarts, but once it got going it went well. The time I lost meant I wouldn't go after the dimmer planetary nebula I had included on my object list in the last post, but that was okay.

All the hardware worked perfectly, although some went untested. The dry air and the gusty to breezy conditions meant the dew preventers weren't needed. It was only around 2 A.M. that frost began to appear, and my scopes stayed clean until the end a little before 3 A.M. The DSLR power supply worked perfectly and the 35Ah battery was barely tested running that and the mount. I used my laptop for PHD with its power supplied by it's own battery augmented with a Duracell 600 battery pack. The Duracell ran down pretty far in the five or so hours, so this might not be a good option for multi-night imaging. For more power conservation I need to find a way to turn off the laptop's display, not simply dim it.

The evening tally was six Arp galaxies and one planetary. In terms of Messier objects it was 9 1/2. Let's see some marathon images:

Leo Triplet (clockwise from NGC 3526 at top, M65, and M66) Together these are Arp 317. M66 is Arp 16.

M49 (right of center, Arp 134)

M60 (left of center, Arp 116) and M59 (right of center)

M87 (Arp 152)

M90 (Arp 76) and M89 at bottom edge

M97 (Owl Nebula) and M108 at bottom edge

All the images are based on 10 three minute exposures with a Canon T2i (at ISO 1600) riding on a TV 102 operating at f/7--except the image of M90, which was 5 three minute exposures at ISO 6400 (see list of mistakes above). These were calibrated with 20 dark frames collected throughout the night as the temperature fell from around 30°to 20°F. They obviously haven't been flatted. I reprocessed them to include synthetic flattening, and now they look a lot nicer!

An inspection of single light frames shows that they surpass visual observations, so why not bring back the idea of an Imaging Messier Marathon? Three minutes at ISO 1600 is about the same as 45 seconds at ISO 6400. 3/4 minute times 110 objects is only 82 minutes; out of a six hour marathon night that leaves four and a half hours for acquisition and composing images. Definitely doable.

That aside, the evening bumped my Arp list count to 26 and my planetary list count to 23. Both lists are about 1/4 done!

Onward to warmer weather!

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