Tag Archives: M15

Nov 27: Several clear hours, sudden cloud.

Saturday evening. There is snow cover on the ground now, and we had freezing rain yesterday, so it certainly feels like winter is in the process of arriving. There were snow flurries this morning, but the sky cleared up mid-afternoon and is still clear now. The temperature is -6 in the dome.

2010-11-27-M15-SC-01-DDPAbout 6:00 I went outside and opened up. I hope to do some data gathering on galaxy NGC2403 tonight, but it is presently behind my large pine tree, and won’t be in the part of the sky I can see until about 9:00. M15 is presently well situated, though, so I am taking a couple of hours of exposure on it, in a mix of 1- and 5- minute subs (thinking I may want the 1-minute subs to mix in to bring out detail in the core, which will otherwise likely be overexposed).

2010-11-27-NGC2403-SC-02-DDPAfter an hour and a half of data gathering on M15, NGC2403 has risen above the hedge, so I’ve switched over to that, about 8:15 PM. I’m gathering 5- and 10-minute subs.

After 1.5 hours, my session was cut short. The sky clouded over completely, very suddenly. Within one 5-minute exposure it went from clear to flat gray. So, I closed everything down and called it a night.

Clear night: More M27 time and some other targets

November 9, 2010. The moon has set and, with DST over but no snow cover yet, it is surprisingly dark in my back yard. It’s clear and not too cold – about 5 degrees.

2010-11-08-M27_0Gathered 2 more hours of data on M27, this time in 15-minute subs. I’ve bumped this up from 10-minute subs just to see the effect. I would expect slightly deeper results, and slightly better S/N, than with more shorter subs. On the other hand, the longer the exposures, the greater the chance that something like a passing plane will ruin them. So I’ll try 15 and see how that works, and maybe push even longer for the next run.

Watching the guiding graph, I note that RA guiding is still tending to oscillate back-and-forth across the zero axis, so I have tried turning the x-aggressiveness down a bit, to 60%, to see if it can further smooth out the curve. Watching the results for a couple of minutes, it does seem to have resulted in a flatter error curve. Continue reading