Monday, June 1, 2015

The June Sky

The arrival of June also heralds the first day of summer and thus, the Summer Solstice, the longest day of the year. Since the length of day/night varies with latitude (the more North you go, the more extreme the lighting), not all people will be having equal length nights on the longest day of the year. For us in the United States, we will have about 8-9 hours from sunset to sunrise. When considering the fact that the transition to true dark consumes about 1 ½ hours on each end of the night, when all is said and done, people living in the Northern Continental U.S. may only have about 5 hours of dark sky observing in June (it never gets truly dark in much of Alaska this time of year). Now the good news: the summer sky is a cosmic picture book.

Cool Constellations
By the time June arrives, some of the Spring constellations are already taking their annual dives out of view. Among these are Corvus, Crater, Hydra, Cancer, and, to a lesser extent, Leo. By the arrival of June, the Big Dipper signpost is starting to become obsolete. As the Dipper begins its annual dive, on the other end of the arc,Corvus and Crater are already disappearing but Bootes and Virgo are coming into their best placements of the year. By the time July comes, you'll only be able to speed on to Spica.
Besides the already mentioned herdsman and virgin, Corona, Hercules, the Summer Triangle (made up of constellations Lyra, Cygnus, and Aquila), Ophiuchus, and Serpens are all flying high at this time of year, too. For those who like to stay up later, Libra and Scorpius are also on the rise, as is deep sky treasure trove Sagittarius along with the ghostly arch across the sky that is the Milky Way. By the time the sky starts to brighten, a fall preview in the form of Pegasus, Andromeda, Aries, Capricorn, Aquarius, and even Pisces Australis is on tap, too.

Planetary Perceptions
Unlike the past few months, June is looking to be a pretty rotten month for watching planets as Mercury and Mars are really non-issues with the former making a quick, anything but impressive appearance in the morning sky come late month and the latter being lost in the Sun's glare all month long. More bad news: June also presents the last real chance to catch Jupiter under a truly dark sky as twilight begins to catch up to the planetary king by months end. That said, the The real treats for June will be Venus and Saturn. Making the origin of its nickname of 'the Evening Star' very evident, Venus shines brightly just after sunset in the Western sky before it too begins to plunge starting mid month. As an item of note, there will be a very close conjunction of Venus and Jupiter on the 30th. At minimal separation, the planets are only separated by about 1/5th angular degree. Moving into the night, Saturn, is well-placed for prime-time (though 'prime-time' is now rather late) observing as it is just about due South at the onset of true night.

The Big Dipper: Signpost to the Stars

Late spring and early summer presents the Big Dipper at its best just as the sky is getting dark. While many people not familiar with astronomy have heard of the Dipper, many people familiar with astronomy do not realize that it makes for a handy guide to the late spring/early summer sky. Starting at the Dipper, follow the arc of its handle to bright orange Arcturus, alpha Bootes and brightest star of the spring sky. From Arcturus and following the same line, speed on to Spica, Virgo's not quite as bright blue alpha star. From there, continue to Corvus, a small, though rather conspicuous trapezoid-like constellation low in the Southern sky and, from there, conclude in Crater, the dimmer, neighboring constellation to Corvus. Moving back to the Dipper, follow the imaginary line created by the stars representing the end of the bowl to Polaris, the North Star. Continuing that line about the same distance through the celestial pole will bring you to 'W'-shaped Cassiopeia, which is just scraping above the Northern horizon this time of year for us at mid-Northern latitudes. Besides aesthetic, the Dipper's pretty practical, isn't it?

Tonight's Sky for June 1: Venus Sets 3 ½ Hours After the Sun
Venus is known as the 'Evening (or Morning) Star' for a reason: it is the brightest thing in the sky just after sunset or before sunrise. That explained, one can now appreciate how good of a show that Venus is putting on right now. Proof? Venus is now setting about 3 ½ after the Sun which, this time of year, puts its set time past midnight, which doesn't occur that often. So, with so much time visible after dark, make it a point to get out and view our nearest planetary neighbor.

No comments:

Post a Comment