The Starry Night, 20

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Leo Trio

The Trio in Leo: M65, M66, and NGC 3628. Eleven 500s subframes, the usual tricks (green channel, flat, dark, averaged, stretched, etc) except no color added. There's a lot more extension available in the galaxies, but revealing that also reveals a noisy, mottled background (see the "spiked" version for a little more). The cure, as usual: more exposure, or use the more sensitive, quieter, CCD. Click here for a 1280 pixel version. Or here for a 1280 pixel version with spikes.


5/8/2010. Home from the neighbors at 11:05. I'd already set the telescope up (I made a flat frame about 6:30 this evening), so all that was left was to plug it into the battery, pull the lens caps, select a target and re-calibrate the mount. I used Denebola to refine the mount's opinions about where it was aimed. Then I slewed to M65 and made a couple of ~1 minute frames to confirm composition. I set the guide star in the corner of the upper left quadrant of the guide-scope's crosshairs, then calibrated the guider, which had no trouble locking onto 73 Leo, a 5.3 magnitude star near M65. Tracking looks very good tonight, seems steadier at 0.5x sidereal rather than 0.25, so that's what I'm using. I have not adjusted focus (and it remains just a little shoddy, with 5.3 pixel FWHM stars and slightly funky point spreads when examined closely).

Gusty winds came from all quarters, ranging from dead calm to 15+ mph. The guider does not give a clue that the telescope is being buffetted. The trees whoosh and roar. Temperature is in the mid-50's, 15 degrees cooler than last night, headed toward a low in the lower 40's. Limiting magnitude is near 5, or just a little deeper.

I'm picking up where M3 left off, with personally significant targets. George Kelley, Jr., introduced me to the Trio in Leo one very dark night by the Holston River at his family farm near Glade Spring, Virginia. I was astonished: it was the first time I had seen such structure in a galaxy, and in three at once, to boot. 8-inch F6 reflector. In honor of the evening, on the order of 35 years distant, I would be tempted to finish this evening with Starlight Nights, a cup of chocolate, and a deeply padded chair beside a coal-fired heater, except, alas, only one of those three props is readily available. Maybe I'll peruse Leslie Peltier's autobiography while the computer churns through the subframes tomorrow.

I picked up the Trio as it emerged on the west side of one last pine and ran 500-second exposures until it approached a second treeline in the high southwest, then made a dark frame while taking down the telescope. Chalk up two more hours of run time on the battery (seven total).

Tweak focus; add more photons



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                   © 2010, David Cortner