June 15—28, 2015
Mt. Washington – The summer solstice, popularly known as the first day of summer, occurs on Sunday, June 21 at 12:38 p.m. EDT. The sun is already within minutes of its highest trajectory in the northern hemisphere sky; we are a week into the earliest sunrises of the year, 5:17 a.m., which continue through June 22. Latest sunsets, 8:34 p.m., occur from June 24 – July 1.
Sundown tonight is 8:31, making for 15 hours and 14 minutes between sunrise and sunset. The longest days of the year, from Friday the 19th – Wednesday the 24th, are 15 hours 16 minutes, which leaves 8 hours 44 minutes from sundown to sunup, the shortest nights of the year. For the rest of June and through the first week of July, nights are barely 8 hours long when dawn and dusk are taken into account. Looking deeper, we might consider the category of astronomical twilight during this period. In the morning, astronomical twilight is when darkness first begins to lift, which is around 3 a.m., and in the evening astronomical twilight is synonymous with nightfall and occurs around 10:45 p.m. at our latitude.
Stargazing would be a late-night affair if it were not for the brightest planets and stars that shine through Earth’s atmosphere soon after sunset. With sunset around 8:30 through the third week of July, planet Venus is an especially captivating star-like light – also known as the evening star – visible in the west within 15 to 30 minutes of our sun’s sinking below the horizon. Venus is now phenomenally bright and increasing in brilliance until July 14. Its apparent magnitude (m) today, -4.35m, increases to -4.47m over the coming month. (The smaller the number the brighter the object.)
At new moon the moon is located between Earth and the sun; the sun lights the moon’s far side and the side facing Earth does not receive light and so is invisible to us: Luna is traveling the sky more or less aligned with the sun. New moon occurs on the 16th at 10:05 a.m. The day after new moon, Thursday the 17th, our natural satellite’s waxing (increasing in size) cycle begins with a thin crescent in the west-northwest, now following the sundown, too closely to be easily seen. Be sure to look on Friday and Saturday, the 18th and 19th, for a delicate crescent below Venus, which is below Jupiter. Moonset on the 17th, 18th and 19th: 9:18, 10:01 and 10:40 p.m., respectively. Venus sets around 11:20 p.m. this week and around 11 p.m. by the 28th.
Planets Jupiter and Venus have been approaching each other for months and, yes, they will soon meet. Find a location with a view to the western horizon to observe the two draw closer together each evening. Extend your arm toward them on the 15th and, making a fist with your hand, insert it into the space between them. That measures about 10 degrees of separation. This should work for children as well as adults. By June 30, the distance between them shrinks to 1/3rd of a degree!
