Inside of a dog...

2025/01/28: I took my first cut at Sharpless 308, the "Dolphin Head" nebula, from the community lot using a 105mm F1.4 Sigma lens, ASI1600MC, and SWSA. Polar alignment was OK, the air reasonably transparent but not perfect. This was the first 30-degree night following a serious cold snap, and it felt luxurious.

105mm F1.4 Sigma at F1.4
60x180s, Gain 300, -15C, Svbony Duoband filter, dark calibrated
SWSA. Make it big!

That's M41 at upper right, Delta Canis Majoris ("Wezen") at lower left. Lots of Lynd Bright Nebulae lace the field. There's a lot of physics going on this field. The central star of the blue bauble here is EZ CMa, a Wolf-Rayet star with a surface temperature of about 89,000 degrees Kelvin. The ultraviolet radiation from the central star as well as the collision of a fierce stellar wind with the interstellar medium produces the blue shell. Stars on the far left edge include Tau CMa (dominating the small cluster NGC 2362) and, just above it, 29 CMa.

You have no idea, and I am not inclined to describe, the number of versions and treatments I have been through with this image. It wouldn't hurt to double the exposure time. Or more. Through clearer air. Working so far left on the histogram is tough. (Hint: channel by channel noise control is sometimes useful.)

2025/01/29. A dark night in the Richlands with Bea and Jeffrey gave me a chance to try a broadband image of Rigel and environs. I set up in bright twilight and used a Bahtinov mask to focus on Rigel. That's the first time I've tried the mask with the 105mm; it works nicely. Then I let the 1600MC run until we headed home about 10:00PM. I tossed the first 30 frames and used the next 150 with the usual aggressive processing (BlurX, Starnet2, noise reduction, starless blend, faux flats, etc etc) to get this:

105mm F1.4 Sigma at F1.4
150x60s, Gain 139, -15C, IV/OR cut, dark calibrated
SWSA. Make this one big, too!

The red streak at top left is Sharpless 278 and is probably worth paying attention to with bigger glass. IC 2118 itself was discovered by William Herschel in 1786 or maybe by Max Wolf in 1891 or maybe in 1909. It's mostly dust doing a lot of forward scattering and reflection of Rigelian light. It might be a supernova remnant or it might not be -- there are an awful lot of mysteries here for a big, relatively easy target.

Cloudy weather looms. Time for a design challenge: I never want to see a fuzzy image from the 400mm again.

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