Thursday, December 26, 2013
The Ellensburg sky for the week of 12/28/13
Saturday: Did you get a new telescope for Christmas? Skyandtelescope.com has a good article on how to get started using it. Go to http://goo.gl/2cJwo. Any observing tip to the night sky should include Jupiter. Jupiter is three fists held upright and at arm’s length above the east horizon at 8 p.m. tonight. A small telescope should reveal Jupiter’s cloud belts and its four largest moons. Last year, the Hubble Space Telescope discovered plumes of water vapor spewing from the surface of Europa, one of these large moons. Astronomers have long thought that Europa has a liquid water ocean below its thick icy crust. But this is the first discovery of water vapor near Europa. For more information about the plumes, go to http://goo.gl/0FaVs8.
Sunday: Saturn is one fist to the upper right of the moon at 7 a.m.
Monday: Venus is about a half a fist above the southwest horizon at 5 p.m.
Tuesday: Forget about that big bright ball in Times Square. You can mark the start of the new year with one of the sky’s own big bright balls. That perennial favorite New Year’s Day marker, Sirius, the brightest star in the night sky, rises to its highest point in the sky a little after midnight on January 1. Thus, when Sirius starts to “fall”, the new year has begun. Look for Sirius about two and a half fists above due south at midnight.
Wednesday: Today is the day we celebrate the anniversary of something new – a new classification of celestial objects. Giuseppe Piazzi discovered Ceres [pronounced sear’-ease], the first of what are now called “asteroids”, on January 1, 1801. Ceres is the largest asteroid in the belt between Mars and Jupiter. At first, Piazzi thought it was a star that didn’t show up on his charts. But, he noted its position changed with respect to the background stars from night to night. This indicated to him that it had to be orbiting the Sun. The International Astronomical Union promoted Ceres to the status of “dwarf planet” in August of 2006.
Thursday: Today’s early morning weather forecast: showers. Meteor showers, that is. The Quadrantid meteor shower peaks late tonight and early tomorrow morning between midnight and dawn. Meteor showers are named after the constellation from which the meteors appear to originate. That makes this shower mysterious because there isn’t any constellation with this name now. The shower was named after Quadrans Muralis, an obsolete constellation found in some early 19th century star atlases. These meteors appear to come from a point in the modern constellation Draco the dragon. This point is about three fists above the northeast horizon at 1 a.m. This year, the waning moon will be rising just before the peak observation time so the dimmer meteors will be obscured by moonlight. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. Most meteors are associated with the path of a comet. This shower consists of the debris from an asteroid discovered in 2003. Keeping with the comet-origin paradigm, astronomers think the asteroid is actually an “extinct” comet, a comet that lost all of its ice as it passed by the Sun during its many orbits.
Friday: Has it been tough to wake up this past week? It should have been because the sunrise has been getting a little later since summer started. I know. I know. December 21 was the shortest day of the year. But, because the Earth’s orbit around the Sun is elliptical and not circular, the Earth does not travel at a constant speed. It moves faster when it is closer to the Sun and slower when it is farther away. This leads to the latest sunrise occurring around the first of January and the earliest sunset occurring in early December, not on the first day of winter, the shortest day of the year. On the first day of winter, however, the interval between sunrise and sunset is the shortest. For more information, go to http://goo.gl/SJC5r.
The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.