Friday, April 26, 2013
The Ellensburg sky for the week of 4/27/13
Saturday: Saturn is opposition tonight. That doesn’t mean that Saturn is a teenager. Opposition means that Saturn is on the opposite side of the Earth as the Sun. When an object is in opposition, it is at its highest point in the sky during the darkest time of the day. Thus, opposition is typically the best time to observe a planet. Saturn is about three fists held upright and at arm’s length above the south horizon at 1 a.m. It is two fists above the southeast horizon at 10 p.m.
If you remember this column from 2/23/2008, 3/8/2009, 3/21/2010, 4/4/11, and 4/15/13, you know that Saturn was also in opposition on those dates. Thus, it is in opposition about 13 days later each year. 13 days is about one twenty-ninth of a year. This implies that it takes Saturn about 29 years to make one orbit around the Sun and get back in line with the same stars again. Saturn’s actual orbital period of 30 years matches this approximation very well.
Sunday: Many ancient philosophers thought the pattern of movement in the heavenly bodies represented a “musica universalis” ore “universal music”. For example, Pythagoras, the right triangle guy, hypothesized that the Sun, Moon, and planets emitted their own characteristic hum based on their orbital motion. Of course we now know that it not the case. But that does not mean astronomy and music are unrelated. At noon Pacific Daylight Time today, Italian pianist and composer Giovanni Renzo will give an online Cosmic Concert with music to accompany beautiful pictures and videos of the night sky. Go to http://goo.gl/YTSgO for more information about the concert and http://goo.gl/QUuLI for a live stream of the concert.
Monday: How many stars can you see in the constellation Leo the lion? This week, you can help answer that question. The organization called GLOBE at Night is looking for people all over the world to count how many stars they can see in one of three constellations. Participants use star charts found at http://www.globeatnight.org/ to observe Leo, Orion, or Crux and compare what they see to the charts. After making the observations, participants can go to the website and add their findings to those of thousands of other observers. The main goal of GLOBE at Night is to research the pattern of light pollution across the globe. A secondary goal is to increase interest in observing and awareness of the night sky. You can find Leo, the best observing choice for Ellensburg, five fists above the southwest horizon at 10 p.m. Regulus, one of the brightest stars in the sky, is at the bottom of the constellation, just over four fists above the southwest horizon.
Tuesday: Are you thirsty. I’ll wait while you get some water. I will NOT wait while Corvus the crow gets you some water. The Greco-Roman god Apollo made this mistake. He sent Corvus the crow to get some water in the cup known as Crater. Some figs distracted Corvus and he waited for them to ripen so he could eat them. When Corvus got back late, Apollo put Corvus and Crater in the sky with the gently tipping cup just out of the reach of the perpetually thirsty crow. Corvus is a trapezoid-shaped constellation about two fists above due south at 11 p.m. Crater is just to the right of Corvus.
Wednesday: Winter must be over because the winter constellations are becoming less visible. Orion is setting due west starting at about 9 p.m. At this time, Orion’s belt is a little more than half a fist above the west horizon and Betelgeuse is nearly two fists above the west horizon. By mid-May, Orion will be lost in the glare of the Sun.
Thursday: Do people think you have a magnetic personality? The star Cor Caroli understands how you feel. Cor Caroli has one of the strongest magnetic fields among main sequence stars similar to our Sun. This strong magnetic field is thought to produce large sunspots that cause the brightness of Cor Caroli to vary. Cor Caroli is nearly straight overhead at 10:30 p.m.
Friday: Jupiter is two fists above the west horizon at 9 p.m.
The positional information in this column about stars and planets is typically accurate for the entire week.