Seeing Stars with Dean Johnson
Tuesday, January 29, 2013 4:02 AM
There will be four things to keep an eye and an ear on in the month of February.
On Feb. 7 and 8, Mercury and Mars will be in a very close conjunction with each other. A conjunction is when two bright objects in the sky make a close pairing.
On Feb. 7, Mars will be just two thirds of a degree to the upper left of Mercury, and on the 8th it will be only one third of a degree to the lower left.
This is a rare conjunction of these two planets because Mercury rarely gets far enough above the western horizon to be seen at all.
Apparitions of Mercury are best seen around vernal equinox and autumnal equinox because the tilt of the Earth's equator is favorable for Mercury to climb high enough above the western horizon to be seen.
If it is clear, both objects can be easily seen in binoculars and can even be seen in the same field of view in a telescope at 100X.
On the 10th and 11th of February, the Moon will be seen very close to the Mars/Mercury conjunction. If you want to see this, you will need a clean, unobstructed western horizon.
On Feb. 15/16 a gymnasium-sized asteroid, 2012 DA14, will pass within 18,000 miles of our planet. This is closer than a geo-sychronos satellite, which orbits at 22,000 miles.
Unfortunately for observers in North America, we will not be able to observe it until the night of Feb. 16 when it is pulling away from Planet Earth and starting to slow (at least to our point of view) and fade.
Observers in Australia, Asia and Eastern Europe will get quite a show because this rock will be magnitude 8 and move at nearly 1 degree (0.8) per minute.
If you stick out your thumb at arms length, your thumb covers roughly one degree of sky. This rock will move that fast every minute.
By the 16th, it will fade to mag. 11, which is barely doable for my telescope and be moving slowly through the constellation of Ursa Minor, better known as the Little Dipper.
Should it hit the Earth (and it won't) the object would set off a blast comparable to the Tunguska explosion over Siberia on June 30, 1908. That knocked down 1,200 square miles of Siberian forest.
We'll know a lot more about 2012 DA14 after its pass, including if it is a rubble pile mass or whether it is a solid iron/rock asteroid.
On Feb. 28, the Moon makes an extremely close pass by the 1st mag. star Spica in the constellation of Virgo the Virgin. It will occult (a Latin word meaning "to hide") the star for observers in Mexico, Central America and South America.
Here in North America, we will see it come very close but still remain visible. It will be a fabulous binocular object to observe.
Finally, Comet PANSTARRS continues to brighten on schedule for observers in the southern hemisphere, but more will be known this time next month.
By late February, we should know if PANSTARRS will be as bright as the brightest stars and whether or not it will have a noticeable tail.
It will break the horizon for northern hemisphere observers in early March after it makes its perihelion passage around the sun.
If you've got a pair of binoculars, break 'em out, dust 'em off and keep looking up!