Astroblog: Seeing Comet C/2017 T1 Near the Beehive Cluster (December 25, 2017)

Friday, December 22, 2017

Seeing Comet C/2017 T1 Near the Beehive Cluster (December 25, 2017)

Location of Comet C/2017 T1 Heinze as seen at 3:45 am ACDST at the latitude of Adelaide, looking north, when it is at transit. Click to embiggen.

Comet C/2017 T1 Heinze is currently near M44, the famous Beehive Cluster, and will be closest to the cluster on Christmas. Although faint it is high enough to be readily accessible telescopically from both Northern and southern hemispheres. In Australia it is best for viewing from 1 am local time until astronomical twilight in the morning, being highest at 3:45 am ACDST at the latitude of Adelaide (and equivalent local times elsewhere in Australia).

Simulated telescopic view of Comet C/2016 R2 PanSTARRS as seen at ACDST at the latitude of Adelaide, when it is at transit. The field of view is approximately than of 10x50 binoculars. Click to embiggen.

In Australia more Northern locations are favoured. However for most locations the comet is over 39 degrees above the horizon at transit. As with C/2016 R2 there are no really good guide stars, but for the 25^th it is roughly between gamma and theta Cancerii. Sadly, the comet is around magnitude 11-12, much dimmer than the cluster and not accessible in binoculars. But still visible in modest telescopes.

Printable B&W charts showing the telescopic view of Comet C/2016 R2 PanSTARRS as seen at 3:45 pm at the latitude of Adelaide, when it is at transit. The large circle is the field of view of 10x50 binoculars small circle is the field of view of a 32mm eyepiece on a 114mm Newtonian. Click to embiggen and print.

You will need a good wide-field eyepiece to see the comet and the cluster in the same field of view. Visually it will look like a fuzzy blob, while not impressive, the Christmas coincidence is nice. For CCD imagers, getting both the comet and the cluster will be a challenge.

The MPC one line ephemeris is:

CK17T010 2018 02 21.7136 0.580751 1.000503 96.9069 102.3228 96.8246 20170904 12.5 4.0 C/2017 T1 (Heinze)

Ephemeris of C/2017 T1 Heinze as seen from Adelaide (Pretty much the same for latitudes from Melbourne to Brisbane).

Date       Distance Mag Ast Twi E Rise         Transit         Altitude Set         Ast Twi B Geo R.A. Geo Dec
24 Dec 2017 0.4132 11.9 22:17:13 22:27:22 03:45:32 +39° 23' 51" 09:00:16 04:13:02 08h 39m 35.7s +15° 41' 55"
25 Dec 2017 0.3879 11.7 22:17:34 22:27:10 03:38:17 +37° 12' 37" 08:46:04 04:13:39 08h 36m 14.0s +17° 51' 46"
26 Dec 2017 0.3633 11.5 22:17:52 22:27:38 03:30:24 +34° 39' 56" 08:30:03 04:14:18 08h 32m 15.0s +20° 19' 24"
27 Dec 2017 0.3398 11.3 22:18:07 22:28:59 03:21:45 +31° 42' 30" 08:11:42 04:15:00 08h 27m 28.7s +23° 07' 41"
28 Dec 2017 0.3175 11.1 22:18:20 22:31:34 03:12:08 +28° 16' 37" 07:50:23 04:15:45 08h 21m 42.0s +26° 19' 41"
29 Dec 2017 0.2966 10.9 22:18:29 22:35:54 03:01:13 +24° 18' 17" 07:25:06 04:16:32 08h 14m 36.4s +29° 58' 34"
30 Dec 2017 0.2774 10.7 22:18:36 22:43:00 02:48:38 +19° 43' 35" 06:54:24 04:17:21 08h 05m 45.3s +34° 07' 04"
31 Dec 2017 0.2604 10.5 22:18:40 22:54:47 02:33:43 +14° 29' 22" 06:16:02 04:18:12 07h 54m 29.3s +38° 46' 40"
01 Jan 2018 0.2458 10.3 22:18:41 23:16:21 02:15:36 +08° 34' 45" 05:26:06 04:19:06 07h 39m 48.6s +43° 56' 14"
02 Jan 2018 0.2342 10.1 22:18:39 --:--:-- 01:52:52 +02° 08' 11" 04:16:36 04:20:02 07h 20m 10.0s +49° 29' 49"

Labels: cluster, comet, telescope