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Comet C/2025 A6 (Lemmon) with M10 & 12
November 4, 2025

We made another trip to Atsion Field in Wharton State Forest, NJ, on November 4, 2025 to observe comet C/2025 A6 (Lemmon), following up on our sessions on October 31 and November 3. On November 4, it would be close to the globular clusters M10 and M12 in Ophiuchus. I picked up the comet with 12x50 binoculars at 5:41 pm EST, when it was at 20.6° altitude in brightish twilight towards the west-southwest, 48 minutes after sunset (4:53 pm) and 44 minutes before the end of astronomical twilight (6:25 pm). The sky was entirely clear, but there was a nearly full Moon at our backs (it would be exactly full at 8:19 am on November 5).
When this picture was captured qt 6:00 pm, Lemmon was at 17.3° altitude and still in brightish twilight mixed with with light pollution from Philadelphia and the intervening suburbs. A distinct short tail, about half a degree long, was evident with the 12x50s, but there was no sign of M10 or 12. A little later, with mounted 18x70 binoculars, I was able to see a central condensation in the coma and a tail about three-quarters of a degree long (difficult to say for sure since it gradually fades away). I was also able to see M10 & 12 with the 18x70s, albeit rather faintly. As the comet sank below 10° altitude, it became increasingly difficult to see with either pair of binoculars, but especially with the 12x50s.
The image above is a single raw frame taken at 6:00 pm with a Canon EOS RP DSLM camera and Canon 200 mm f/2.8L telephoto lens on a fixed tripod. It was manually exposed 1.6 seconds at f/2.8, ISO 1600, daylight white balance. Using Canon's Digital Photo Professional 4, it was lightly adjusted, cropped to a field about 5.9° wide x 4.0° high, then converted to this JPEG. M10 is 3.3° above-left of Comet Lemmon, M12 is 2.6° above-right of it and M10 & 12 are 3.3° apart. The brighter star in the upper-left corner is magnitude 4.8, 30 Ophiuchi; the brighter star lower down near the left edge is 23 Oph, mag 5.2. Mouseover for labels. I was surprised these nominal 6+ magnitude clusters showed up at all in this simple snapshot, in view of the twilight, light pollution (both the Moon and man-made LP) and the low altitude. Comet Lemon was about magnitude 4.5 based on contemporaneous reports at COBS.
Here's a chart of Lemmon for November 8, 2025, 6 pm EST, +/- eight days at two-day intervals (labeled version).

Comet C/2025 A6 (Lemmon)
October 27, 2025

I went to Thompson's Beach, NJ, again on October 24, 2025 to observe comet C/2025 A6 (Lemmon), hopefully with unaided eyes. I picked it up at 6:50 pm EDT while still in brightish twilight, and as the sky darkened, a distinct short tail was evident with the 12x50s; sunset was at 6:05 pm and twilight ended at 7:34 pm. However, I was unable to convincingly see Lemmon with unaided eyes due to the presence of a 33% illuminated Moon and haze-like clouds moving into the comet's area, as shown in the picture above. I also spotted C/2025 R2 (SWAN) with the 12x50s, but it was more difficult than October 24 at Carranza under a moonless sky.
This is a single raw frame taken at 7:19 pm with a Canon EOS RP DSLM camera and a Sigma 50 mm, f/1.4 Art lens on a fixed tripod. It was manually exposed 2 seconds at f/2.0, ISO 3200, daylight white balance. Using Canon's Digital Photo Professional 4, it was lightly adjusted and converted to this JPEG; it's uncropped for a field about 40° wide x 27° high. The comet is in the upper-left quadrant, Arcturus is at the bottom-right and Alphecca is is near the top-middle. Unfortunately, I just missed catching the recurrent nova T CrB in the picture, but I did check the respective area with the 12x50s and there was no sign of it. Mouseover for labels. Here's a crop (labeled version) of the upper left corner, about 23.5° wide x 15.8° high, that better shows Comet Lemmon.
Shortly before sunset, at 5:44 pm, I took a snapshot of the clouds towards the west. Canon EOS RP + Sigma 20 mm f/1.4 Art lens, handheld. Exposed automatically 1/250 second, f/5.6, ISO 100. It was cropped vertically only to provide a 16:9 ratio for a field 84° wide x 54° high.

Comet C/2025 A6 (Lemmon)
October 24, 2025

In the month of October, 2025, we were blessed with two relatively bright comets in the evening sky, C/2025 R2 (SWAN) and the comet pictured above, C/2025 A6 (Lemmon). Both are easily visible now with binoculars, and Lemmon is visible with unaided eyes from a suitably dark location. SWAN is currently in the constellation Aquila and Lemmon is in Serpens Caput. This snapshot of Lemmon was captured at 7:28 pm EDT on October 24, 2025, from Carranza Field in Wharton State Forest, NJ.
It's a single raw frame taken with a Canon EOS RP DSLM camera and a Canon 200 mm, f/2.8L telephoto lens on a fixed tripod. It was manually exposed 4 seconds at f/2.8, ISO 3200, daylight white balance. Using Canon's Digital Photo Professional 4, it was lightly adjusted, then cropped to 58% of the original linear dimensions yielding a field 5.9° wide x 4.0° high, and converted to this JPEG. The tail extends about 3° in this picture, and visually with 18x70 binoculars, nearly a degree of tail was easily seen. The brighter star above-right of the coma (about 39 arc min apart) is magnitude 5.7, HD 136138.

The Crescent Moon, Venus and Regulus
September 19, 2025

On the morning of September 19, 2025, the thin Crescent Moon, 5.5% illuminated 2.4 days before New, passed close to the planet Venus, which in turn was close to the first magnitude star Regulus, in Leo. At the time, the Moon was 36 arc minutes (0.60°) from Venus, center-to-center, slightly more than the nominal 0.5° diameter of the Moon. It was 33.5 arc minutes (0.56°) from Venus to Regulus. Visually, they were a lovely sight, although Regulus was overwhelmed by the bright Moon and Venus.
This snapshot was taken at 6:15 am EDT from Swede Run in Moorestown, NJ, with a Canon EOS RP DSLM camera and a Canon 400 mm, f/5.6L telephoto lens on a fixed tripod. It was manually exposed 1/50 second at f/5.6, ISO 3200, daylight white balance. Other than cropping to 77% of the original linear dimensions yielding a field 3.95° wide x 2.64° high, and size reduction, the only post adjustment was setting white balance to 6000 K. Mouseover labels.

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