Tag Archives: NGC2403

A cold night, and more time on NGC2403

Tonight was the first clear night in a couple of weeks. It was quite cold – about minus 13 degrees, and there is an inch of snow on the ground.

NGC2403-SC-b-04-curveThe observatory computer wouldn’t start at first – the “keep just above freezing” setting of my heater apparently wasn’t working, and everything was frozen. I ran the heater on full for 1/2 hour, bringing the dome interior up above freezing, then the computer started ok. Once it is going, it generates enough internal heat to keep going ok.

I took some additional exposure time on NGC2403 in a mix of 5-, 10-, and 15-minute subs, another 2 hours 20 minutes total. Guiding is extremely stable so close to NCP, so the tracking is very clean.

The image here is a combination of tonights 2:20 hours and an hour taken a month or so ago.

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.

Nov 10: More M27, start 2 new targets

Tonight looks like a repeat of last night – the sky is clear and the CSC says excellent transparency all night. I’ve opened the dome at 7:30 PM, and am taking another 2 hours of M27 in 15-minute subs, to add to the data collected the last couple of nights.

I just noticed that for the first 500 seconds of the first 900-second sub, I forgot to turn PEC on. It was still guided, but more correction needed than I would have liked. So I may end up discarding this first sub – we’ll see how it turns out. The other 1.75 hours will be PEC-corrected in any case.
Sure enough, in post-processing Maxim recommended discarding the first sub (and another) for poor star-roundness, so I went along with this. The result, with 4.5 hours of data, is starting to look nice – detail in the outer gas envelope is beginning to show well.

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