Winter constellation preview

 The air was calm and the temperature was about 31° F at 4:30 am MST on 02 Nov.  The 11.1-d gibbous moon had already set about an hour and a half earlier.  There was very strong green airglow above the southern horizon.

The next three images were obtained with an Olympus E-M1iii camera and a Leica 9mm f/1.7 lens with a Hoya Sparkle-6 filter.

 

The bright star near the top of the last two images is the planet Jupiter, currently the brightest "star" in the night sky at magnitude −2.3.

 The previous evening (01 Nov), Comet C/2025 A6 (Lemmon) was showing no sign of the intense solar storm that hit it on Halloween evening, 31 Oct.  The tail was once again smooth.

01 Nov.  Meade 80mm f/5 refractor.

about to disappear behind the mountain.

The next nearest star. The comet puts on a show.

"Alpha Centauri" is the mostly-correct answer to the question "What is the nearest star?".  Alpha Centauri is actually a three-star system, comprising two sun-like stars in a solar-system-size orbit, and a third dim and distant red-dwarf companion.  This third star, Proxima Centauri, is slightly closer to us (4.22 ly) than its two larger siblings.  So, after the Alpha-Centauri system, what is the next nearest star?  The answer is Barnard's Star in the constellation Ophiuchus.  Barnard's Star is a red dwarf just under 6 ly distant and shines at magnitude 9.5, meaning it can't be see without a telescope.

The red dot in the center is Barnard's Star, the next nearest star after the Alpha Centauri system.

 The images in tonight's (31 Oct) session were obtained with a Meade 80mm f/5 achromatic (doublet) refractor and an Olympus E-M1iii camera.

Comet C/2025 A6 (Lemmon) was putting on quite a show, but I didn't realize it until I processed the images afterward.  The comet was apparently hit by an intense burst of solar wind, which warped and knotted the ion tail.  I was watching the comet with a Celestron C5 Schmidt-Cassegrain telescope, but none of this drama was visible to the eye.

 

Comet C/2025 A6 (Lemmon), 7:38 pm MDT.

About to disappear, 29 min later.  8:07 pm MDT.

 

Here is an animation tracking on the head of the comet, covering the 29-min span:

 Based on a reported distance of 116.8 million km, the change in angular separation of that knot in the tail from the comet's head works out to about 86 km/s relative velocity.

Moon, comet, star clusters

 The moon is 8.7 days past new, waxing gibbous, and lighting up the sky.  The faux-daylight blue is very strong in photographs.  I used three lenses tonight: Olympus 75mm f/1.8, Canon FD 300mm f/4 L, and an Astro-Tech AT80EDT f/6 refractor (480 mm focal length).

GIbbous moon through the double-pane bedroom window.  AT80EDT.

 

C/2025 A6 (Lemmon) over Bristol Head.  Olympus 75mm.

Canon FD 300mm.

AT80EDT

Just for fun, while I had the telescope mounted (on a ZWO AM3), I snapped some pictures of a couple star clusters.  The bright moonlight is not ideal. However, the measured sky brightness was sqml=20.28, which is darker than a moonless night in Santa Fe. Both exposures: 30 sec, unguided.

M13, a famous globular cluster in the constellation Hercules.

 

M11, the "Wild Duck Cluster", an open cluster in Scutum (part of the Milky Way).

Wednesday comet

 The evening sky remains clear, and in spite of the moon, Comet Lemmon is still an attractive target.  Trying out different lenses keeps things from getting too repetitive.  Tonight I used the Canon FD 300mm f/4 L lens at its native focal length with a Sony A7iii camera on a ZWO AM3 mount. These are unguided 30-sec exposures.

Comet C/2025 A6 (Lemmon) setting over Bristol Head.

It is challenging to get a picture that is not crisscrossed with satellite trails.  These two images were selected from a total of 16.

 

Three comets Tuesday night

 The sky was bright with the first-quarter moon (6.8-d) on Tuesday night.  Even so, I was able to photograph three comets using an old Canon FD 300mm f/4 L lens with a Metabones 0.71x Speed Booster on an Olympus E-M1iii camera.  The resultant focal length is 213 mm @ f/2.8.  The camera was mounted on a ZWO AM3 harmonic drive.

I followed comet C/2025 A6 (Lemmon) visually with a 2x54 wide-field binocular.  The magnitude-4 coma was easy to see and a short trace of the tail was visible in the moonlight.

comet C/2025 A6 (Lemmon).  Canon FD 300mm f/4 L @ 213 mm f/2.8.

about to set behind the Bristol Head ridgeline

 Comet C/2025 R2 (SWAN) is currently in the constellation Aquarius.  It is about magnitude 7 and is decreasing in brightness.

comet C/2025 R2 (SWAN)

 Comet C/2024 E1 (Wierzchos) is in the constellation Hercules.  It is about magnitude 13 (very faint), but is increasing in brightness.

Comet C/2024 E1 (Wierzchos) is the green blob at the center of the image.

 

Monday-evening comet

Comet C/2025 A6 (Lemmon) is still visible, even with the 5.8-day moon high in the south last night.  I watched it with a 2x54 wide-angle binocular and a 60mm f/6 refractor at 12x.  Some wide-angle photographs were obtained with an old Minolta MD 85mm f/2 lens on a Sony A7iii camera and an Olympus 75mm f/1.8 lens on a E-M5iii camera.

Minolta MD 85mm

 The triangle of stars to the right of the comet are Gamma, Kappa, and Beta in the constellation Serpens Caput.

Olympus 75mm 

 

Olympus 75mm

Even with the moonlight it is still possible to pick out the two distinct tails: the narrow blue ion tail and the broader yellow dust tail.

Moonlight makes comet viewing difficult

The 4.9-d moon was still in the sky as Comet Lemmon set behind Bristol Head.  This extra illumination makes viewing and photographing the comet more difficult.  I could still see the bright coma without optical aid, but the tail will become harder to see as the moon becomes brighter night by night.

Photographed with a Sony A7iii + Samyang 85mm AF f/1.4 FEII lens.

Comet C/2025 A6 (Lemmon) setting over Bristol Head, 26 Oct.