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Guide to the Night Sky by Tre Gibbs - July 2018

By Tre Gibbs, L.A.A.S.

This month will be a good time to view multiple planets without having to be up just before sunrise, as Saturn and Mars return to our evening skies.

Venus, The Goddess of Beauty and Love, and Jupiter, The Roman King of the Gods, have been gracing our evening skies together for a little over a month now, Venus low in the west northwest and Jupiter in the southeast, both appearing shortly after sunset, when the sky gets dark enough to see their glow. As Jupiter continues to move westward, Venus has begun her slow, long decent towards the glare of the sun, on her way to becoming The Morning Star by the end of the year.

Early in the month, Saturn, in Sagittarius The Archer, rises in the southeast at sunset. Saturn is so far away (roughly 840 million miles - or 76 light minutes) that it doesn’t stand out nearly as much as Venus and Jupiter. It simply appears as a prominent, non-twinkling star. Mars, The God of War, in Capricornus The Sea Goat, rises in the southeast around 11:00 - 11:30 pm, with it’s unmistakeable reddish hue. Jupiter, in the constellation of Libra The Scales, appears high in the south at sunset, which makes it ideal for viewing. Even with a pair of good binoculars, you should be able to see four of it’s 69 moons, known as the Galilean Satellites, since Galileo discovered them back in 1610. Looking through binoculars, they will appear as small pinpricks of light, all in a straight line. Galileo first thought that they were background stars until, over time, he noticed that they stayed with Jupiter - even as Jupiter moved across the sky. They also appeared sometimes on the left side of Jupiter, sometimes on the right…and different combinations, too - two on either side of Jupiter, one on one side, three on the other… That’s when Galileo realized something astounding: these things were moons that orbited Jupiter, which suddenly meant Earth was not the only center of motion in the universe - a truly radical challenge to the way of thinking by The Catholic Church at the time. This discovery would eventually lead to Galileo imprisoned by the church, spending the rest of his life under house arrest. FYI, the Catholic Church eventually issued a formal apology to Galileo, in 1992, 350 years after his death. So grab a pair of binoculars - or better yet, get a telescope and see these history changing objects for yourself!

By month’s end, Saturn (still in Sagittarius) appears in the south southeast at sunset, while Mars rises at sunset, much like Saturn did at the beginning of the month. Jupiter (still in Libra) will appear high in the south southwest at sunset, and all three wanderers will appear to keep moving slightly further west every day, as Earth speeds past them, continuing her orbit around our nearest star, The Sun.

The moon will be passing by all of the above mentioned planets, which is a great way to make certain of which planet you are seeing. On the 15th, the thin waxing (getting bigger) crescent moon is incredibly close and to the left of Venus, low in the west just after sunset. Five days later, on July 20th, the moon has moved further east in its orbit around Earth, now half full and will travel the sky with Jupiter. Four days after that, on the 24th, the moon - still moving eastward away from the sun and getting even bigger - is now right above Saturn. Finally, three days after that, on the 27th, the moon is directly opposite the sun, the biggest it will get (FULL!) and pairs up with Mars for the evening, both traveling the night sky as a pair. FYI - this particular full moon is known as “The Full Buck Moon” since this is the time of year young bucks grow new antlers. And speaking of the moon, it’s slowly leaving us! On July 16th, 1969, Apollo 11 launched from Cape Kennedy in Florida. Four days later on July 20th, Neil Armstrong would be the first man to walk on the moon. In addition to placing an American flag and a commemorative plaque on the moon, he also placed something that is still in use today - a lunar laser ranging reflector, which is a two foot wide panel covered with mirrors. With the help of a laser beam shot from Earth and reflected back to us, we can measure the ever growing distance between us and the moon, which is about 3.8 centimeters per year. So don’t take the moon for granted - it won’t always be there. Yet another reason to KEEP LOOKING UP !

So until next month, KEEP LOOKING UP !

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