Saturday, April 26, 2025
Seeing Comet C/2025 F2 (SWAN) from Australia (maybe)
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| Evening
sky from Friday, May 2 as seen from Adelaide at 17:59 ACST (30
minutes after sunset), C/2025 F2 SWAN is present in
the twilight although not likely visible. In the coming days it will rise higher in the twilight but will only be a binocular object at best. Similar views will be seen from the rest of Australia at roughly the equivalent local time (30minutes after sunset, click to embiggen). | Evening sky on Tuesday, May 6 as seen from Adelaide at 18:25 ACST (60 minutes after sunset), C/2025 F2 SWAN may be visible in the twilight in binoculars in the Hyades. The inset is the approximate binocular view at this time. Similar views will be seen from the rest of Australia at roughly the equivalent local time (60 minutes after sunset, click to embiggen). | Evening sky on Monday, May 12 as seen from Adelaide at 18:20 ACST (60 minutes after sunset), C/2025 F2 SWAN may be just visible in the twilight in binoculars in Orion's Shield. The inset is the approximate binocular view at this time. Similar views will be seen from the rest of Australia at roughly the equivalent local time (60 minutes after sunset, click to embiggen). |
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| Path of C/2025 F2 SWAN in the western evening sky from Friday, May 2 to 1 June as seen from Adelaide at 17:59 ACST (30 minutes after sunset. Black&White chart suitable for printing. The image is at civil twilight to show the path of the comet over the month, however, the best time to observe is nautical twilight (60 minutes before sunrise). The greyed out section is below the horizon. (click to embiggen and print). | Binocular chart of the path of C/2025 F2 SWAN in the western evening sky from 6 May to 11 May. Black&White chart suitable for printing (click on the image to embiggen and print). The image is at nautical twilight (60 minutes before sunrise). The circle is the approximate field of view of 10x50 binoculars. | Biinocular chart of the path of C/2025 F2 SWAN in the western evening sky from 10 May to 19 May. Black&White chart suitable for printing (click on the image to embiggen and print). The image is at nautical twilight (60 minutes before sunrise). The circle is the approximate field of view of 10x50 binoculars. |
If comet C/2025 F2 SWAN survives perihelion on the 1st of May, it will be visible low in the twilight. Unlike comet C/2024 G3 it will not be visible to the unaided eye, even through theoretically visible (magnitude 6), its position low in the twilight murk means binoculars will always be needed.
You will need a clear, level horizon like the ocean or desert to see the comet. It will fade rapidly after perihelion. This and its location in the horizon murk means the window of opportunity for binocular viewing is narrow.
The earliest we can reasonably see the comet here in Australia is May 6th, when it is roughly 5 degrees (about a hand-span) above the western horizon at nautical twilight. Although roughly magnitude 6 it will be hard to see in the twilight.
As C/2025 F2 SWAN passes through the Hyades in Taurus and into Orion it will rise into darker skies, but be fading fast, so sill be difficult to see, despite good guide stars. See printable charts above. Print them out and use with a red-light torch (or a standard torch with red cellophane over it) so as to not disturb your night vision.
Labels: binocular, C/2025 F2, comet
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