Wednesday, June 29, 2016

The Ellensburg WA sky for the week of 7/2/16

Saturday: Look straight up at midnight. The head of Draco the dragon will be looking straight down on you. The brightest star in the head is called Eltanin. If you chose to wait a VERY long time, Eltanin will be the brightest star in the night sky. Currently 154 light years away, it is moving towards Earth and will be only 28 light years away in about 1.3 million years, claiming the title as brightest star.

Sunday: Jupiter is nearly two fists held upright and at arm’s length above the west horizon at 10 p.m. So is the NASA Juno spacecraft because tomorrow it reaches its destination after a nearly five-year trip to Jupiter to study the giant planet’s core, atmosphere, and magnetic field. By learning more about Jupiter, astronomers hope to learn more about the formation and evolution of the Solar System. If the latest blockbuster, Independence Day: Regurgitate disappointed you, watch the more engaging sci-fi-film-like trailer about the Juno mission at

Monday: Hot enough for you? Don’t blame the Earth-Sun distance. Surprisingly, the overall temperature of the Earth is slightly higher in July, when the Earth is farthest from the Sun, than in January, when it is closest. That’s because in July, the Northern Hemisphere is tilted towards the Sun. (This is the real cause of the seasons.) The Northern Hemisphere has more land than the Southern Hemisphere. Thus, in July, the large amount of Northern Hemisphere land heats up the entire Earth about two degrees Celsius warmer than in January. In January, the watery Southern Hemisphere is tilted toward the Sun. But, water does not heat up as fast as land so the Earth is a few degrees cooler. The distance between the Earth and Sun is its greatest today, 152.1 million kilometers. This is called aphelion from the Greek prefix “apo” meaning “apart” and Helios, the Greek god of the Sun.

Tuesday: Tonight, while you are taking a break from looking at an explosion of fireworks, the NASA Kepler spacecraft is taking a break after finding an “explosion” of exoplanets. In May, astronomers announced the discovery of 1,284 new planets, more than doubling the number of planets discovered by Kepler. 550 of those are small and possibly rocky. Nine of those are in the habitable zone of their host star. And this is only the beginning. The Kepler spacecraft is monitoring the brightness of over 156,000 stars in the constellations Cygnus the swan and Lyra the lyre. This region is midway between the bright stars Deneb and Vega. It is about the size of your hand held at arm’s length and is about six fists held upright and at arm’s length above due east at 11 p.m. For more information about this find, go to

Wednesday: Mars is two fists above due south at exactly 9:21 pm. The bright reddish star Antares is one and a half fists above due south at exactly 10:30 pm. Saturn is two fists above due south at exactly 10:37 pm. I still love formulaic writing. Notice that these times are about a half hour earlier than when these same objects were above due south eight days ago. In general, distant objects rise earlier from night to night. Stars rise about four minutes earlier each night, as evidenced by our observation tonight and last Tuesday.

Thursday: Last week, I wrote about Mizar. This week, I need to warn you not to confuse Mizar with its rhyming brother Izar in the constellation Bootes. Izar is also a binary star with about the same apparent brightness. And both were featured in different episodes of Star Trek. Izar was featured in the Star Trek episode “Whom Gods Destroy” from the original series. It is the base of Fleet Captain Garth, a former big shot in the federation and one of Kirk’s heroes before he went insane. Garth kidnaps Kirk and Spock before eventually being out smarted. Mizar doesn’t play as big a role in its episode. It is the star of the home world of one of the alien species in The Next Generation episode “Allegiance”. Izar is one fist above the bright star Arcturus and seven fists above the south horizon at 10 p.m. Mizar is seven fists above the northwest horizon at this time.

Friday: Venus is just above the northwest horizon at 9:15 p.m.

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

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