Saturday: The bright star Spica is about a half a fist held at arm’s length to the lower right of the Moon. They are three fists above the south-southeastern horizon at 10:00 p.m.
Sunday: Today is Father’s Day, the day to celebrate the person who gave you a father: your grandmother. In fact, celebrate this with your child by getting them the book “Woman in Science” by Rachel Ignotofsky (http://www.readwomeninscience.com/). This creatively drawn book highlights the contributions of 50 pioneers of science from Hypatia to Katherine Johnson, the main character in the recent movie “Hidden Figures”.
Monday: Last night, the Sun reached its highest declination (the official name for sky latitude) of 23.5 degrees above the celestial equator. The celestial equator is the line that divides the northern sky from the southern sky. In Ellensburg, the Sun is about seven fists held upright and at arm’s length above the south horizon at 1:00 p.m. (noon standard time). Contrary to popular belief, the Sun is never straight overhead in Ellensburg or anywhere else in the 48 contiguous states. The northernmost portion of the world where the Sun can be directly overhead is 23.5 degrees north latitude. In ancient times, the Sun was in the constellation Cancer the crab on the first day of summer. Hence, 23.5 degrees north latitude has the nickname "Tropic of Cancer". Because the Earth wobbles like a spinning top, the Sun's apparent path through the sky changes slightly over time. Now, the Sun is in the constellation Taurus the bull on the first day of summer. However, citing the high cost of revising all of the science books, geographers are not changing the name of 23.5 degrees north latitude to "Tropic of Taurus". The first day of summer is often called the summer solstice. However, astronomers refer to the summer solstice as the point in the sky in which the Sun is at its highest declination above the celestial equator. Summer starts when the Sun is at the summer solstice point. This year, that happens tonight at 8:30 p.m. Pacific Daylight Time.
Tuesday: Saturn is one fist above the southeastern horizon and Jupiter is a half a fist above the east-southeastern horizon at 12:30 a.m.
Wednesday: At 10:00 p.m., Venus is about a half a fist above the west-northwestern horizon. Mars is a fist to the upper left of Venus. You’ll find it in the midst of the Beehive Cluster, one of the closest star clusters to Earth. It consists of about 350 stars, about 50 of which can be seen with binoculars on a dark night.
Thursday: “Mom, I can’t sleep. It is too light out!” A poor excuse you say? Good astronomy skills, I say. The latest sunset of the year happens this weekend. Surprisingly, the earliest sunrise and the latest sunset do not both happen on the longest day of the year, the day of the summer solstice. The earliest sunrise occurs just before the longest day and the latest sunset occurs just after the longest day. This phenomenon relates to the angle of the Sun’s path near rising and setting. In Ellensburg, that angle is about 66 degrees above the southern horizon at noon near the first day of summer. Because of the Earth’s orbit, which causes the Sun’s apparent motion, the angles are not symmetric. The asymmetries in orbital angles leads to the asymmetry in rise and set times. This year, the sun sets at about 9:01 p.m. between June 22 and June 29 as viewed from Ellensburg, WA. Find sunset data for your location at https://www.timeanddate.com/.
Friday: Don’t wait until next weekend to watch those wimpy firecracker shows. Find the hypergiant star Rho Cassiopeiae. Astronomers think that Rho Cassiopeiae will likely go supernova (explode) in the near future. Of course, for stars, “near future” might mean today. It might mean 20,000 years from now. Rho Cassiopeiae is in the constellation Cassiopeia the queen. At 11:00 tonight, Cassiopeia looks like the letter “W” about two and a half fists above the north-northeastern horizon. Rho Cassiopeiae is about a finger’s width to the right of the rightmost star in the “W”. Once you find it you’ll be thinking, “Big deal, I can hardly see it.” Although it is barely visible to the naked eye, it is actually very bright. It is the 20th most luminous star in the sky, a whopping 550,000 times more luminous than the Sun
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.
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