Comet Catalina in Morning Sky

A new comet is emerging in the morning sky. Though it is faint, Comet Catalina (C/2013 US10) will pass near a few distinct celestial targets to help you find it with a telescope or binoculars. The comet was discovered in 2013 by the Catalina Sky Survey and is making its inaugural--and only--visit to the inner solar system. Sky & Telescope offers star charts and describes how Comet Catalina Sails into Northern Skies. Some key dates for observers are December 7, 2015, and January 1, 14, and 17, 2016.

In late November while the comet is passing upward throught the plane of the solar system, the comet is low in the east southeast, but conveniently in line with the planets dancing in the morning sky. The image below depicts a greatly exaggerated tail (my fault with software) around 6:30 a.m. EST. Still, you can hop down and left from bright Jupiter to reddish Mars to brilliant Venus to the small smudge of Comet Catalina, provided the bright moon doesn't wash out the sky.

On December 7, a thin crescent moon has moved into the picture just tabove Venus, from the perspective of the mid-northern latitudes. The three objects form a tight triangle as shown below, again with the tail length and brightness greatly exaggerated. Some scientists suggest the comet then may be sixth or fifth magnitude, still challenging to see in the brightening sky of twilight.

The proximity of the moon to Venus is especially significant on December 7. Don't stow your binoculars or telescope quite yet. Later in the day--literally midday--the moon occults Venus!

Comet Catalina keeps moving north above the solar plane, passing abreast the red giant star Arcturus on the first morning of 2016. To find it, follow the handle of the Big Dipper and "arc to Arcturus." Reminder #3, the comet will not be bright as depicted in my simulation. Astrophotographers will be sharing their images at Spaceweather's Realtime Comet Gallery.

Then after December 14 the comet buzzes by Alkaid, the end star of the handle of the Big Dipper. Three days later it is fairly close to the second star in the handle, Mizar and its companion Alcor. Mizar itself is a good telescope target, for it's actually a double double star.

Of course, comets are fickle and can readily become a bust. Remember the highly anticipated Comet ISON, which rounded the sun on Thanksgiving 2013? See Comet Festival for details about ISON, the sungrazing comet from the Oort Cloud. Then, too, we openly admitted no one knew how the comet would evolve. Comet Catalina has already passed perihelion, so it will continue to be a diminishing patch of fuzz--no theatrics expected.

As we cross into the new year there is always cause for optimism. With the one-time visitor heading back into deep space and fading rapidly, we always hope for a random comet to appear surprisingly and to shine brightly for all to see.