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Comet Catalina has now re-appeared in the morning sky after passing perihelion on November 15th, some 123 million kilometres (76 million miles) from the Sun. Its current northern trajectory means that it's finally becoming easily visible from mid-latitude northern locations; before perihelion it was primarily a Southern Hemisphere object. Sadly Catalina hasn't brightened as previously predicted and seems likely not to reach easy naked eye visibility. However, it's still visible with binoculars / small scopes and should remain so for many more weeks to come. Current predictions put peak magnitude in early 2016 at just under 6. Of course, comets are notoriously unpredictable and it may suddenly brighten spectacularly, so keep watching!

Comet Catalina on August 10, 2015 (credit - Kenny Astrom/Siding Spring)

At the end of November, Catalina is visible low down towards the east during morning twilight. In the same region of sky are Venus, Mars and Spica west of the comet with Arcturus to the north. Brilliant Venus is by far the brightest of the four objects. At magnitude -4.3, it's 250x brighter than Mars (mag. +1.6). Arcturus and Spica are both first magnitude stars with orange giant Arcturus (mag. -0-04) the fourth brightest in the night sky. Spica shines at mag. +1.0 and therefore brighter than Mars but still 2.5x fainter than Arcturus. For comparison, Catalina on November 21st shone at mag. +6.1, 60x fainter than Mars.

Catalina Sky Survey

Catalina was discovered by R. A. Kowalski of the Catalina Sky Survey on October 31, 2013. The Catalina Sky Survey (CSS) is a project based at the University of Arizona that searches for potentially hazardous asteroids that could impact the Earth. It utilizes 3 large telescopes to image the sky almost every clear night, except around full Moon, in the hunt for near-Earth objects (NEOs). To date the project had discovered hundreds of asteroids and comets.

Location and star chart

Catalina continues on its current northern path through Virgo until Christmas Eve when it moves into Boötes. From northern latitudes its visibility will keep improving as it moves higher in the sky although from southern latitudes it's hardly observable after November. The comet is now moving away from the Sun but at the same time moving closer to Earth. As December progresses it should brighten slightly and appear larger with a coma of the order of 0.5 degrees and a tail extending for up to 5 degrees possible. The best time to look in December is between the 10th and 20th when the Moon won't interfere.

Comet Catalina just before sunrise from mid northern temperate latitudes on December 10, 2015 (credit:- Stellarium)

At the beginning of January, Catalina passes closes by Arcturus and on January 17th it approaches to within 0.72 AU or 108 million kilometres (67 million miles) of Earth. At this time it could still be around 6th magnitude.

The finder charts below show the positions of Catalina from November 18th to December 18th, 2015.

Comet Catalina (C/2013 US10) Finder Chart from November 18th to December 18th, 2015 (credit:- freestarcharts)

Comet Catalina (C/2013 US10) Finder Chart from November 18th to December 18th, 2015 - pdf format (credit:- freestarcharts)

C/2013 US10 (Catalina) Data (at epoch November 15, 2014)

NameC/2013 US10 (Catalina)
TypeComet
DiscovererCatalina Sky Survey
Discovery dateOctober 31, 2013
Perihelion (AU)0.82290
Eccentricity1.00040
Orbital period (years)unknown
Inclination (degrees) 148.8733
Longitude of ascending node (degrees)186.1371
Perihelion November 15th, 2015

(C2013/US10) Catalina Data Table

DateRight AscensionDeclinationMag.Distance from Earth (AU)Constellation
01-Nov-201514h 26m 12s-25d 17m 31s6.41.821Hydra
02-Nov-201514h 25m 54s-24d 53m 19s6.41.820Libra
03-Nov-201514h 25m 36s-24d 29m 01s6.31.819Libra
04-Nov-201514h 25m 18s-24d 04m 38s6.31.817Libra
05-Nov-201514h 24m 60s-23d 40m 07s6.31.814Libra
06-Nov-201514h 24m 42s-23d 15m 29s6.31.811Libra
07-Nov-201514h 24m 25s-22d 50m 41s6.31.807Libra
08-Nov-201514h 24m 07s-22d 25m 44s6.21.802Libra
09-Nov-201514h 23m 50s-22d 00m 37s6.21.797Libra
10-Nov-201514h 23m 33s-21d 35m 17s6.21.791Libra
11-Nov-201514h 23m 16s-21d 09m 46s6.21.785Libra
12-Nov-201514h 22m 60s-20d 44m 01s6.21.778Libra
13-Nov-201514h 22m 44s-20d 18m 03s6.21.770Libra
14-Nov-201514h 22m 28s-19d 51m 49s6.11.762Libra
15-Nov-201514h 22m 12s-19d 25m 19s6.11.753Libra
16-Nov-201514h 21m 57s-18d 58m 31s6.11.743Virgo
17-Nov-201514h 21m 42s-18d 31m 26s6.11.733Virgo
18-Nov-201514h 21m 28s-18d 04m 01s6.11.723Virgo
19-Nov-201514h 21m 14s-17d 36m 16s6.11.711Virgo
20-Nov-201514h 21m 00s-17d 08m 10s6.11.700Virgo
21-Nov-201514h 20m 47s-16d 39m 40s6.11.687Virgo
22-Nov-201514h 20m 34s-16d 10m 46s6.11.674Virgo
23-Nov-201514h 20m 22s-15d 41m 27s6.11.661Virgo
24-Nov-201514h 20m 10s-15d 11m 40s6.01.647Virgo
25-Nov-201514h 19m 59s-14d 41m 25s6.01.632Virgo
26-Nov-201514h 19m 48s-14d 10m 40s6.01.617Virgo
27-Nov-201514h 19m 38s-13d 39m 22s6.01.601Virgo
28-Nov-201514h 19m 28s-13d 07m 30s6.01.585Virgo
29-Nov-201514h 19m 19s-12d 35m 02s6.01.569Virgo
30-Nov-201514h 19m 10s-12d 01m 56s6.01.552Virgo
01-Dec-201514h 19m 01s-11d 28m 09s6.01.534Virgo
02-Dec-201514h 18m 54s-10d 53m 38s6.01.516Virgo
03-Dec-201514h 18m 46s-10d 18m 22s6.01.498Virgo
04-Dec-201514h 18m 39s-09d 42m 17s6.01.480Virgo
05-Dec-201514h 18m 33s-09d 05m 19s6.01.461Virgo
06-Dec-201514h 18m 26s-08d 27m 26s6.01.441Virgo
07-Dec-201514h 18m 20s-07d 48m 34s6.01.422Virgo
08-Dec-201514h 18m 15s-07d 08m 40s6.01.402Virgo
09-Dec-201514h 18m 09s-06d 27m 38s6.01.381Virgo
10-Dec-201514h 18m 04s-05d 45m 26s6.01.361Virgo
11-Dec-201514h 17m 59s-05d 01m 57s6.01.340Virgo
12-Dec-201514h 17m 54s-04d 17m 08s6.01.319Virgo
13-Dec-201514h 17m 49s-03d 30m 53s6.01.298Virgo
14-Dec-201514h 17m 44s-02d 43m 06s6.01.277Virgo
15-Dec-201514h 17m 39s-01d 53m 42s6.01.255Virgo
16-Dec-201514h 17m 34s-01d 02m 34s6.01.234Virgo
17-Dec-201514h 17m 28s-00d 09m 36s5.91.212Virgo
18-Dec-201514h 17m 22s00d 45m 20s5.91.190Virgo
19-Dec-201514h 17m 15s01d 42m 21s5.91.168Virgo
20-Dec-201514h 17m 08s02d 41m 35s5.91.147Virgo
21-Dec-201514h 17m 00s03d 43m 10s5.91.125Virgo
22-Dec-201514h 16m 52s04d 47m 15s5.91.103Virgo
23-Dec-201514h 16m 42s05d 53m 59s5.91.082Virgo
24-Dec-201514h 16m 31s07d 03m 32s5.91.060Virgo
25-Dec-201514h 16m 19s08d 16m 03s5.91.039Boötes
26-Dec-201514h 16m 05s09d 31m 44s5.91.018Boötes
27-Dec-201514h 15m 50s10d 50m 43s5.80.997Boötes
28-Dec-201514h 15m 33s12d 13m 14s5.80.976Boötes
29-Dec-201514h 15m 13s13d 39m 25s5.80.956Boötes
30-Dec-201514h 14m 52s15d 09m 29s5.80.936Boötes
31-Dec-201514h 14m 27s16d 43m 35s5.80.917Boötes

See also

Comet Catalina (C/2013 US10) moves past Kemble's Cascade during the last week of February 2016. Visible with binoculars and small telescopes from northern and tropical latitudes.
Comet Catalina (C/2013 US10) now fading as it recedes from Earth. Currently moving through the far northern constellations. Remains visible with binoculars and small telescopes.
Comet Catalina (C/2013 US10) remains visible with binoculars and small telescopes at it moves northwards. This month offers the last good chance to catch a glimpse before it fades significantly.
Comet Catalina (C/2013 US10) moves past Arcturus as it heads north during January. Remains visible with binoculars and small telescopes.
Comet Catalina (C/2013 US10) an early morning binocular and small telescope object
Comet Catalina (C/2013 US10) edges towards naked eye visibility
Comet Catalina (C/2013 US10) remains visible in the evening from Southern and Equatorial Latitudes during September 2015
Comet Catalina (C/2013 US10) now visible with binoculars from Southern and Equatorial Latitudes