The Sky This Week, June 7 – 14, 2016 !

The Sky This Week, 2016 June 7 – 14

The Moon, planets, and stars over the National Mall!
Saturn, 2016 May 28, 04:50 UT
imaged from Morattico, Virginia

The Moon returns to the evening sky this week, cruising through the springtime constellations as she waxes toward First Quarter, which occurs on the 12th at 4:10 am Eastern Daylight Time. She starts the week as a slender crescent perched between the last of winter’s stars, the twin Stars of Gemini, castor and Pollux, and the star Procyon. Between the evenings of the 9th to the 11th she passes the bright star Regulus in Leo and the planet Jupiter. She ends the week a few degrees north of the bright star Spica on the evening of the 14th.

By the end of the week we’ll be closing in on the summer solstice and the year’s shortest nights. Those of you who have been awakened by the Sun lately take heart, since the year’s earliest sunrise will occur on the 13th. On that morning Old Sol greets Washingtonians at 5:42 am EDT. By the time the solstice occurs on the 20th the Sun rises at 5:43 am, and when we see our latest sunsets on June 27th the Sun rises at 5:45 am. The discrepancy between the dates of earliest sunrise and latest sunset are a result of many factors that involve the Earth’s non-circular orbit around the Sun and the so-called “equation of time”, which is used to correct “apparent” solar time (as kept by a sundial) with “mean solar time” based on a uniform 24-hour day. These effects are most noticeable around the times of the solstices, particularly the winter solstice. We have a detailed explanation on our website for those of you who wish to peruse the fine details.

These short nights definitely limit what you’ll be able to see during their brief duration. Fortunately we have several bright planets, the Moon, and familiar star patterns like the Big Dipper to entertain us. If you’re in the Washington area on the evening of the 10th, stop by the Washington Monument grounds and visit us at the annual “Astronomy Night on the National Mall“. This program, sponsored by Hofstra University, attracts many of the areas local astronomical institutions and amateur astronomers to share their research and telescopes between 6:00 and 11:00 pm EDT. We’ll have safe solar observing telescopes to look at the Sun until sunset, then other telescopes to view the evening’s offerings. The venue is the northeast corner of the monument grounds on 15th Street and Constitution Avenue, NW. If it rains we’ll try again on the following night at Catholic University.

Jupiter will be one of the highlights of the event on the Mall. You’ll find Old Jove high in the west as evening twilight falls, and he remains a prominent sight until the late evening hours. On the evening of the 10th he will be flanked by his four bright Galilean moons, two on each side of Jupiter’s striped disc.

Mars will also be a feature of the star party on the Mall. Just past opposition, the red planet’s disc is about half the apparent size of Jupiter’s, but it is still about as large as it will get during the current apparition. If the night presents steady air we should see some of the red planet’s more interesting surface features. Until the advent of the space age the nature of these dark smudges on the otherwise pink-hued disc were the source of great speculation, but today we can associate them with some of the most interesting geologic features in the solar system.

Saturn should be visible to the telescopes on the Mall by 10:00 pm, and the ringed planet should offer a fine sendoff for the last hour of the star party. Two years ago I showed Saturn to hundreds of people at the same event, and almost everyone refused to believe that what they were looking at was real. I can assure you that once you’ve seen it you won’t forget it!


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