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Is comet SWAN25F in outburst?

Artyom Novichonok All Messages By This Member #33548 开云体育 Dear colleagues, Today's morning I observed SWAN25F visually, and, surprisingly, it was a very bright, small and condensed object, easily visible in the astronomical twilight under under bright aurora and moonlight with an 8 cm refractor. So, the comet may have undergone an outburst or may be brightening very rapidly. SWAN25F 2025 Apr. 06.02 UT: m1=8.1, Dia.=2.5', DC=7 ...8-cm R (24x) ...Chalna fields (Karelia, Russia). Astronomical ? twilight ?(Sun ?-15 deg), ?bright ?aurora, ?moonlight. Zenithal SQM-L = 19.9. Air temp -9 °C. **** The image (5x60 s, F=55 mm) was taken just before visual observation. Best regards, A. Novichonok. SWAN25F_2025-04-06_Novichonok_55mm_5x60s.jpg
Nick James All Messages By This Member #33549 Artyom My astrometry in a 9 arcsec aperture had the comet at 11.1 this morning (April 6.17). It was 12.1 at this time yesterday. I was surprised how bright it was. I got a total magnitude of 9.6 yesterday using the green channel of a colour CMOS and comphot. I haven't done that processing yet today. Nick. toggle quoted message Show quoted text On 06/04/2025 07:23, Artyom Novichonok via groups.io wrote: Dear colleagues, Today's morning I observed SWAN25F visually, and, surprisingly, it was a very bright, small and condensed object, easily visible in the astronomical twilight under under bright aurora and moonlight with an 8 cm refractor. So, the comet may have undergone an outburst or may be brightening very rapidly. SWAN25F 2025 Apr. 06.02 UT: m1=8.1, Dia.=2.5', DC=7 ...8-cm R (24x) ...Chalna fields (Karelia, Russia). Astronomical twilight (Sun -15 deg), bright aurora, moonlight. Zenithal SQM-L = 19.9. Air temp -9 °C. ****
michaeljaeger All Messages By This Member #33552 Hi Yes, it has brighten significantly, but it does not appear to be a outburst. Our images (april 6 2.20 - 3.05 UT) showed the comet at 8m4 (measured from the green images). Coma and tail: 5', 2° pa 298 and 30' pa 303 Michael ------ Originalnachricht ------ Von "Nick James via groups.io" <comets@...> An [email protected] Datum 06.04.2025 08:44:50 Betreff Re: [comets-ml] Is comet SWAN25F in outburst? toggle quoted message Show quoted text Artyom My astrometry in a 9 arcsec aperture had the comet at 11.1 this morning (April 6.17). It was 12.1 at this time yesterday. I was surprised how bright it was. I got a total magnitude of 9.6 yesterday using the green channel of a colour CMOS and comphot. I haven't done that processing yet today. Nick. On 06/04/2025 07:23, Artyom Novichonok via groups.io wrote: Dear colleagues, Today's morning I observed SWAN25F visually, and, surprisingly, it was a very bright, small and condensed object, easily visible in the astronomical twilight under under bright aurora and moonlight with an 8 cm refractor. So, the comet may have undergone an outburst or may be brightening very rapidly. SWAN25F 2025 Apr. 06.02 UT: m1=8.1, Dia.=2.5', DC=7 ...8-cm R (24x) ...Chalna fields (Karelia, Russia). Astronomical twilight (Sun -15 deg), bright aurora, moonlight. Zenithal SQM-L = 19.9. Air temp -9 °C. **** swan25F20250406UT220t305_3.jpg
Bob King All Messages By This Member #33553 Hi everyone, I can confirm Artyom's observation from Duluth, Minn.:? April 6.4 UT, 38-cm reflector, x64, magnitude?~8, DC=6, 3 arc-minute coma. Responded better to Swan filter.? Considerably brighter and more condensed compared to my previous observations on April 4.4 (mag. 9.5). There was even a visual hint of blue-green color. Bob? toggle quoted message Show quoted text On Sun, Apr 6, 2025 at 1:23?AM Artyom Novichonok via <artnovich=[email protected]> wrote: Dear colleagues, Today's morning I observed SWAN25F visually, and, surprisingly, it was a very bright, small and condensed object, easily visible in the astronomical twilight under under bright aurora and moonlight with an 8 cm refractor. So, the comet may have undergone an outburst or may be brightening very rapidly. SWAN25F 2025 Apr. 06.02 UT: m1=8.1, Dia.=2.5', DC=7 ...8-cm R (24x) ...Chalna fields (Karelia, Russia). Astronomical ? twilight ?(Sun ?-15 deg), ?bright ?aurora, ?moonlight. Zenithal SQM-L = 19.9. Air temp -9 °C. **** The image (5x60 s, F=55 mm) was taken just before visual observation. Best regards, A. Novichonok.
Nick James All Messages By This Member #33554 Hi all, I get the following total magnitudes and coma diameters with comphot using a 51mm, f/4.9 refr. + ASI2600MC. Green channel vs Gaia G DR3: 2025 April 5.157 9.6 2.3' 2025 April 6.150 8.0 3.8' so considerably brighter and bigger than yesterday. Transparency was probably a bit better this morning but conditions and time were similar. Nick James, Chelmsford (970). toggle quoted message Show quoted text On 06/04/2025 07:23, Artyom Novichonok via groups.io wrote: Dear colleagues, Today's morning I observed SWAN25F visually, and, surprisingly, it was a very bright, small and condensed object, easily visible in the astronomical twilight under under bright aurora and moonlight with an 8 cm refractor. So, the comet may have undergone an outburst or may be brightening very rapidly. SWAN25F 2025 Apr. 06.02 UT: m1=8.1, Dia.=2.5', DC=7 ...8-cm R (24x) ...Chalna fields (Karelia, Russia). Astronomical twilight (Sun -15 deg), bright aurora, moonlight. Zenithal SQM-L = 19.9. Air temp -9 °C. **** The image (5x60 s, F=55 mm) was taken just before visual observation. Best regards, A. Novichonok.
Mike Olason All Messages By This Member #33562 Comet SWAN25F on the morning of 2025 April 6 1144UT was magnitude 8.4 as calculated from 12x10 second images in an aperture diameter of 3.5', the coma was about 3' wide and the tail extended beyond the field of view of these images at a position angle of 301 degrees from the coma. The comet coma is certainly rich in diatomic carbon and evidently dust poor. SWAN25F_20250406_1141_molason.jpg SWAN25F_20250406_1144_molason.jpg
Alex Scholten All Messages By This Member #33565 This morning (April 7th) comet C/2025 F2 was clearly visible in my 20cm: m = 7.7 (DC = 7 coma 3').? This was 1 magnitude brighter than two days ago. (altitude of the comet 15 degrees; altitude of the sun -14 degrees) Alex
Christian Harder All Messages By This Member #33566 开云体育 Hi all, I observed him the last five nights : 3.4.2025,? 10" Dobson, homeplace, 9.5mag 4.4.2025,? 8" Dobson, homeplace, 9.0mag 5.4.2025, 8" Dobson, Danmark, 9.0mag 6.4.2025, 8" Dobson, Danmark, 7.9mag? ? 7.4.2025, 10" Dobson, homeplace, 7.9mag I think he had an outburst. CS Christian Am 07.04.2025 um 10:19 schrieb Alex Scholten via groups.io: toggle quoted message Show quoted text This morning (April 7th) comet C/2025 F2 was clearly visible in my 20cm: m = 7.7 (DC = 7 coma 3').? This was 1 magnitude brighter than two days ago. (altitude of the comet 15 degrees; altitude of the sun -14 degrees) Alex

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