One full moon or two? It’s a timely question

Did two full moons occur in May as some calendars list or will they occur in June as others maintain? Surely there can’t be a question as to which month houses two full moons? Well, yes, there can depending upon where in the world you are and what system of time you are using.

Most astronomers use Greenwich Mean Time, or GMT, or Universal Time, or UT. By this time system the first full moon falls in the early morning hours of June 1. But by Eastern Daylight Time in North America, which is two time zones to the west and four hours earlier, it falls on the evening of May 31. Thus the same full moon can fall in May or June depending upon what time frame you use.

Month aside, how did the second full moon in the same month get named a “Blue Moon”? This actually came about by an article in a 1946 issue of Sky & Telescope that misinterpreted a definition in the 1937 Maine Farmer’s Almanac. Generally the term was used to describe any event very unlikely to occur. One popular phrase used to describe such an event was, “I’ll marry you m’lady when the moon is blue!” The young lady in question is unlikely to get a marriage proposal!

Focus on the planets

Mercury is low on the western horizon about an hour after sunset early in June. The innermost planet will be visible during the first week of the month before fading into obscurity.

Venus shines brightly far to the upper left, where it is the brightest object in the night sky after the moon. The two bright stars to the right of Venus are Castor and Pollux of Gemini.

Mars continues to climb higher and brighten in the east at dawn. Although still dim and distant Mars is now visible to the naked eye and identifiable by its reddish-orange hue.

Jupiter is climbing on the southeastern horizon at dusk and remains visible throughout the night. The best time to observe Jupiter’s surface features and major moons will be in the later nighttime hours.

Saturn is to the upper left of Venus in the west at dusk where the two will treat viewers to a spectacularly close meeting on June 30.

Uranus in Aquarius and Neptune in Capricorn rise well after midnight and can be spotted with a small telescope and finder charts. A new finder chart will appear in the July 2007 issue of Sky & Telescope.

June events

5 Jupiter is at opposition or opposite the sun from our vantage point. The giant planet rises in the east at sunset and sets in the west at dawn.

8 Moon in last quarter, 7:43 a.m.

12 Moon at perigee or closest approach to Earth today.

13 Venus brushes by the Beehive cluster in Cancer in the evening sky.

15 New moon, 11:14 p.m.

18 Look to the western horizon at dusk where Venus, the moon, and Saturn are closely grouped in a line from lower right to upper left.

21 Summer solstice, 2:11 p.m. The sun has reached the point where it is the farthest north of the celestial equator. This is the first day of summer and now the daylight hours will begin to shorten. The sun is entering the astrological sign of Cancer at the solstice.

22 The sun enters Gemini on the ecliptic but astrologically has only just entered Cancer. The moon is in first quarter, 9:14 a.m.

24 The moon is at apogee or farthest distance from Earth.

30 Full moon, 9:49 a.m. The full moon of June is known variously as the Rose Moon, Honey Moon, Hay Moon, or the Strawberry Moon. Look to the west at dusk tonight for an extremely close pairing of Venus and Saturn. Sunrise, 4:52 a.m.; sunset, 8:25 p.m.

Send astronomical queries to Clair Wood at cgmewood@aol.com or care of the Bangor Daily News, Lifestyle Desk, P.O. Box 1329, Bangor, Maine 04402.