Wednesday, June 8, 2016

The Ellensburg WA sky for the week of 6/18/16

Saturday: Father’s Day is tomorrow. Do you have a dad so great that you wish you could write his name in the galaxies? Now you can. UK astronomer Steven Bamford has developed a computer program that finds images of galaxies that resemble different letters. Just enter the words here and the program spells it out in galaxies. Here’s the new Daily Record title page

Sunday: Tonight’s full moon is in the constellation Sagittarius the Archer. This month, Sagittarius may be thinking of shooting strawberries instead. Some Native American tribes call the June full moon the strawberry moon to honor (or remember) the short strawberry harvesting season. A more descriptive name is the Short Moon because the full moon is above the horizon for the least amount of time in June – only eight hours. Summer full moons are always above the horizon less than winter full moons. Since the full moon is on the complete opposite side of the Earth as the Sun, the full moon is going to be in the sky whenever the Sun is not in the sky, namely the entire night. During the summer, the nights are shorter so the full moons time above the horizon will also be shorter.

Monday: Today is the first day of summer, the day that the Sun reaches 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 point above the celestial equator. Thus, summer starts when the Sun is at the summer solstice point. This year, that happens at 3:34 p.m. Pacific Daylight Time.

Tuesday: Saturn and Mars are both nearly exactly two fists above the south horizon at 11 p.m. Saturn is a little east of due south and Mars is a little west of due south.

Wednesday: When it is sitting low in the western sky, many people mistake the star Capella for a planet. It is bright. It has a slight yellow color. But, Capella is compelling on its own. It is the fourth brightest star we can see in Ellensburg. It is the most northerly bright star. It is a binary star consisting of two yellow giant stars that orbit each other every 100 days. At 10 p.m., Capella is two fists above the north-northwest horizon. If you miss it tonight, don’t worry. Capella is the brightest circumpolar star meaning it is the brightest star that never goes below the horizon from our point of view in Ellensburg.

Thursday: Jupiter is two and a half fists above the west-southwest horizon at 10 p.m.

Friday: Nearly 400 years ago, Galileo viewed the Pleiades star cluster through his telescope and saw that the seven or so stars in the region visible to the naked eye became many more. There are two main types of star clusters. Open star clusters are groups of a few dozen to a few thousand stars that formed from the same cloud of gas and dust within our galaxy. Stars in open star clusters are young as far as stars go. Globular clusters are groups of up to a few million stars that orbit the core of spiral galaxies such as our own Milky Way. One of the most well known star clusters is the globular cluster in Hercules, an object that is fairly easy to find with binoculars. First find Vega, the bright bluish star five fists above the east horizon at 11 p.m. Two fists above Vega is a keystone shape. Aim your binoculars at the upper left hand star of the keystone. The globular cluster is one third of the way to the rightmost star of the keystone. It looks like a fuzzy patch on the obtuse angle of a small obtuse triangle. If you don’t know what an obtuse angle is, you should not have told your teacher, “I’ll never need to know this stuff”.

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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