2023a3 20241010 1900 mmattiazzo

n case you didn't see this post on comets-ml,
I made a rare (photographic) observation for the records.
Whilst everyone was concentrating on the nucleus, swinging towards evening
skies,
I attempted to capture the dust tail in the morning sky from the southern
hemisphere, with success.
C/2023 A3 Tsuchinshan-ATLAS dust tail on 2024 October 10 at 18:15UT.
using a Canon 6D + Sigma 200mm lens. 12x30sec iso3200. FOV 15deg. North
lower left. from Swan Hill, Victoria, Australia. 35S 144E
This tail measured at least 45 degrees from the nucleus in PA 252 towards U
Hydra (marked on image) and is made up of fine "tail end" paticles.
Whilst imaging this, I was interrupted by a magnificent display of aurora
australis happening towards the south. 
This was not a mistaken observation of an aurora and has been independently
verified by Rob McNaught, who captured it over 2 consecutive mornings (Oct
9-10).
The PA of the tail measured at 252, is in perfect alignment with the orbit. 
41 degrees south of ecliptic PA 293.
Comet orbital inclination = 139 ( 41 degrees south of  ecliptic)
It is definitely not an ion tail.
You can currently see the tail make its way through SOHO LASCO C3, well lit
up by the high phase angle.
https://soho.nascom.nasa.gov/data/realtime/c3/512/
it will be interesting to see how long it takes to pass completely into the
evening sky.
Earth is crossing the comets orbital plane on October 15, resulting in a
significant dust tail (PA 71) and anti-tail (PA249), rivalling 1957 comet
Arend-Roland.

Kind regards,
Michael Mattiazzo
Swan Hill, Victoria 3585