Comet Section

John Drummond, Director of the Comet and Meteor Section, will provide regular updates to facilitate Comet and Meteor observations by RASNZ members and the astronomic community.

More observations from the Southern Hemisphere would be highly valued by the international community. Over the coming months John and key Section members, will provide information on observing equipment, observing tips and where to send the observations to encourage and support more observers to join this effort from New Zealand.

Naked eye comet to grace New Zealand skies in late September and October 2024

A comet discovered in 2023 is starting to put on a nice display over Southern Hemisphere skies. Currently (~27 September 2024) C/2023 A3 (Tsuchinshan-ATLAS) is in the morning sky rising about 1-1.5-hours before the Sun. John Drummond (Gisborne) reported being just able to see it with the naked eye on the 26th of September 2024. The comet was about magnitude 3.5 (although a magnitude 3.5 comet is about 1.2 magnitudes fainter than a magnitude 3.5 star with its stellar point). To see the comet, find a clear, low eastern horison (preferably without light pollution) and sweep along the horison with binoculars. Look east. Sweep right to left for about 30-degrees, then raise them up half a field, then sweep left to right and so on until you see a comet with a tail. This should be done about an hour before sunrise. Also, point a camera in that direction and try to capture it with 10-30 second exposures.

With binoculars it is a fine sight, displaying an impressive tail. It will get brighter and closer to the Sun (elongation-wise) over the next two weeks. Perihelion occurred on 27 September 2024. From Earth, it will seem closest to the Sun on 10 October 2024 when the elongation is just a few degrees. On about the 12th it should be seen very low in the western sky shortly after sunset. Each night it will climb higher in the sky and set later, so should be easier to see. It will probably be brightest around the 10-12 October. Seen from Earth, the Sun may illuminate the dust particles in the coma/tail and make it appear much brighter. This is called the forward scattering of light. It’s akin to seeing a water sprinkler being lit up if the Sun is behind it from where you’re standing. The comet may possibly be seen during the daytime sky with the naked eye around 10 October 2024; however, this is only a slim possibility. Also, it will be close to the Sun (~3-4-degrees), so extreme care should be taken.

From mid-October it will get fainter and continue to climb into the evening sky through Virgo, Serpens, and Ophiuchus. By the end of October, it probably won’t be a naked-eye object anymore.

The following ephemerides is from GUIDE 9.1 planetarium software. Note, the magnitude (‘mag’) is suggestive only and may be very different. ‘Elong’ is elongation – how many degrees the comet is from the Sun.


Tsuchinshan-ATLAS (C/2023 A3)


Date              RA          dec         r   delta  mag Elong Con
----              --     -----------      -   -----  --- ----- ---
27 Sep 2024 10h42m56.24s -06 06' 10.9" 0.3929 0.9623 3.2 23.0 Sex
28 Sep 2024 10h46m02.15s -06 04' 13.3" 0.3915 0.9186 3.1 23.0 Sex
29 Sep 2024 10h49m54.87s -06 00' 46.3" 0.3920 0.8748 3.0 22.8 Sex
30 Sep 2024 10h54m41.47s -05 55' 42.3" 0.3944 0.8313 2.9 22.5 Leo
 1 Oct 2024 11h00m29.47s -05 48' 53.0" 0.3987 0.7885 2.8 21.9 Leo
 2 Oct 2024 11h07m26.80s -05 40' 08.8" 0.4047 0.7466 2.7 21.0 Leo
 3 Oct 2024 11h15m41.65s -05 29' 18.6" 0.4125 0.7061 2.7 19.8 Leo
 4 Oct 2024 11h25m22.29s -05 16' 09.2" 0.4218 0.6674 2.6 18.2 Leo
 5 Oct 2024 11h36m36.62s -05 00' 25.9" 0.4326 0.6309 2.6 16.3 Leo
 6 Oct 2024 11h49m31.59s -04 41' 52.7" 0.4446 0.5971 2.6 14.0 Vir
 7 Oct 2024 12h04m12.17s -04 20' 14.9" 0.4578 0.5664 2.6 11.3 Vir
 8 Oct 2024 12h20m40.07s -03 55' 21.5" 0.4719 0.5393 2.6 8.2 Vir
 9 Oct 2024 12h38m52.17s -03 27' 10.0" 0.4870 0.5164 2.6 5.1 Vir
10 Oct 2024 12h58m39.01s -02 55' 51.4" 0.5028 0.4979 2.6 3.5 Vir
11 Oct 2024 13h19m43.85s -02 21' 54.4" 0.5192 0.4843 2.6 5.9 Vir
12 Oct 2024 13h41m42.85s -01 46' 06.7" 0.5363 0.4758 2.7 10.1 Vir
13 Oct 2024 14h04m06.93s -01 09' 31.7" 0.5538 0.4725 2.8 14.6 Vir
14 Oct 2024 14h26m24.90s -00 33' 20.5" 0.5716 0.4744 2.9 19.3 Vir
15 Oct 2024 14h48m07.32s +00 01' 19.3" 0.5899 0.4811 3.1 23.8 Vir
16 Oct 2024 15h08m49.75s +00 33' 33.2" 0.6084 0.4924 3.2 28.1 Vir
17 Oct 2024 15h28m14.77s +01 02' 44.9" 0.6271 0.5078 3.4 32.0 Ser
18 Oct 2024 15h46m12.23s +01 28' 37.6" 0.6460 0.5267 3.6 35.6 Ser
19 Oct 2024 16h02m38.44s +01 51' 10.4" 0.6651 0.5487 3.8 38.9 Ser
20 Oct 2024 16h17m34.65s +02 10' 33.8" 0.6843 0.5733 4.0 41.7 Ser
21 Oct 2024 16h31m05.38s +02 27' 04.9" 0.7036 0.6000 4.2 44.2 Oph
22 Oct 2024 16h43m17.07s +02 41' 03.9" 0.7229 0.6285 4.4 46.4 Oph
23 Oct 2024 16h54m17.02s +02 52' 51.3" 0.7423 0.6585 4.6 48.2 Oph
24 Oct 2024 17h04m12.67s +03 02' 46.5" 0.7617 0.6896 4.7 49.8 Oph
25 Oct 2024 17h13m11.17s +03 11' 06.8" 0.7812 0.7217 4.9 51.2 Oph
26 Oct 2024 17h21m19.13s +03 18' 07.7" 0.8006 0.7546 5.1 52.3 Oph
27 Oct 2024 17h28m42.54s +03 24' 02.3" 0.8200 0.7880 5.3 53.3 Oph
28 Oct 2024 17h35m26.72s +03 29' 01.7" 0.8394 0.8220 5.5 54.1 Oph
29 Oct 2024 17h41m36.34s +03 33' 15.4" 0.8588 0.8562 5.6 54.7 Oph
30 Oct 2024 17h47m15.53s +03 36' 51.2" 0.8782 0.8907 5.8 55.2 Oph
31 Oct 2024 17h52m27.84s +03 39' 55.8" 0.8975 0.9255 6.0 55.7 Oph

Got any photos of it? I’d love to see them. Please send to kiwiastronomer@gmail.com .

John Drummond

RASNZ Comet Section