NIGHT SKY HAPPENINGS

The Sky for June 2016
By Faylene Roth

Bright stellar objects zigzag across the northern half of the night sky. From east to west: Altair (Aquila), Deneb (Cygnus), Vega (Lyra), Arcturus (Boötes) southward to Spica (Virgo), northwestward to Jupiter then Regulus (Leo) and the twin stars of Gemini low on the horizon.

Draco the dragon wraps around Ursa Minor (Little Dipper). Look for its head halfway between Vega and the bottom of the Little Dipper. Its body extends northward then twists south and wraps around the Little Dipper trailing westward between Ursa Minor and Ursa Major (Big Dipper).

Faint constellations in the southern sky include Libra—a trapezoidal box west of the head of Scorpius. About 30̊ west of Libra another trapezoid forms Corvus the crow. The half circle next to it forms the Crater. The water snake Hydra meanders west to east over a span of about 90 ̊ very low on the southern horizon. Its head is about 15 ̊ below the line of the ecliptic (halfway between the head of Leo and Gemini). Its body zigzags below Crater and Corvus extending almost to Libra.

Twilight extends the period of daylight in three stages at each end of the day. Morning twilight begins with astronomical twilight—about 1-1/2 hours (nearly 2 during summer months) before sunrise—as the eastern horizon brightens. Nautical twilight continues—as the overhead sky turns blue and color returns to the surrounding landscape—for another 30-40 minutes. The final stage—civil twilight—provides adequate light for most outdoor activities for the half hour before the sun crests the horizon. The opposite progression occurs after sunset.

MOON HAPPENINGS
May 6 – Dark skies throughout the night before and after the new moon (1:29pm).
May 13– Dark evening skies. A waning last quarter moon rises after midnight.
May 21– Full moon (3:14pm) rises at 8:23pm.
May 29– Moonlit evening skies continue until the waxing last quarter moon sets after midnight.
(The moon rises later each day—as little as 30 minutes to as much as one hour. Time of moonrise and moonset may also be delayed in mountainous terrain.)

VISIBLE PLANETS
Evening (Before Midnight)
Mars –The brightest object in the southern sky (magnitude -1.5), its red disc visible at evening twilight west of the head of Scorpius, is paired with red star Antares (in Greek the rival of Mars) about 15 ̊ southeastward. Mars sets before morning twilight.
Saturn – Its golden orb (magnitude +1.0)—east of the head of Scorpius and about 15 ̊ northeast of Mars—forms a triangle with Mars and Antares. Earth passes between the Sun and Saturn on the night of June 2/3 at 1:00am.
Jupiter – By evening twilight its brilliant white sphere (magnitude -2.1) shines high in the western sky on the ecliptic about 15 ̊west of Regulus (Leo) with Spica (Virgo) about 45 ̊ eastward. Jupiter sets soon after midnight.

Morning (At Morning Twilight)
Mercury –Brilliant (-0.2 magnitude) but tiny and very low on the eastern horizon, it may be visible for early risers just above a waning crescent moon in the early twilight of June 1. Mercury rises higher in the morning sky until midmonth then begins to recede back towards the horizon.
Saturn – appears very low on the western horizon.
Apparent magnitude values range from -4 to +6 for most planets and visible stars. The lower the value the brighter the object. A decrease of 1.0 magnitude is 2.5 times brighter.

NO MAJOR METEOR EVENTS
Minor meteor activity occurs from a variety of radiants during the first half of June, especially visible in the dark skies after midnight.

MOON HAPPENINGS
June 4 – New moon (9:00pm) provides dark skies for several nights.June 12 – Waxing first quarter moon lights the evening sky then sets soon after midnight.
June 20 – Full moon (5:02am)—rising at 8:55pm—occurs on the solstice.
June 27 – Dark evening skies return with the waning last quarter moon rising after midnight.

Primary Sources: USGS; U.S. Naval Observatory; Your Sky at http://www.fourmilab.ch/yoursky/
To find out when the space shuttle and International Space Station are visible from your location, go to: http://spaceflight.nasa.gov/realdata/sightings/index.html and click on Sighting Opportunities.

The star chart approximates the sky from astronomical twilight to midnight. As the night and month progresses, the constellations shift toward the northwest. The celestial equator is measured in hours (h). The ecliptic is measured in degrees

Note: Hold your hand at arm’s length to measure apparent distances in the sky. The width of the little finger approximates 1.5̊. Middle, ring, and little finger touching represent about 5̊. The width of a fist is about 10̊. The fist with the thumb extended at a right angle equals 15̊. The hand stretched from thumb to little finger approximates 20̊-25̊. The diameter of both the full moon and the sun spans only 0.5̊. Adjust for the size of your hand.