Get out your telescopes! The first week in June will bring a lunar eclipse and a rare transit of Venus! Here’s a look at what’s in store:
June 4, Partial Eclipse of the Moon
This eclipse favors the Pacific Ocean; Hawaii sees it high in the sky during the middle of their night. Across North America, the eclipse takes place between midnight and dawn. The farther east one goes, the closer the time of moonset coincides with the moment that the Moon enters the umbra. In fact, over the Northeastern U.S. and eastern Canada, the only evidence of this eclipse will be a slight shading on the Moon’s left edge (the faint penumbral shadow) before moonset.
Over the Canadian Maritimes, the Moon will set before the eclipse begins. At maximum, more than one-third of the Moon’s lower portion will be immersed in the dark umbral shadow.
Moon Enters Penumbra: 4:46 a.m. – Moon Enters Umbra: 5:59 a.m. – Maximum Eclipse: 7:03 a.m. – Moon Leaves Umbra: 8:07 a.m. – Moon Leaves Penumbra: 9:20 a.m. – Magnitude of the Eclipse: 0.376
A Rare Transit of Venus Over the Face of the Sun
On June 5—6, 2012, the passage of Venus in front of the Sun is among the rarest of astronomical events; rarer even than the return of Comet Halley every seventy-six years. Only six transits of Venus are known to have been observed by humans before: in 1639, 1761, 1769, 1874, 1882, and most recently in 2004.
The beginning of the transit will be visible from all of North America, Greenland, extreme northern and western portions of South America, Hawaii, northern and eastern portions of Asia including Japan, New Guinea, northern and eastern portions of Australia, and New Zealand. The end will be visible over Alaska, all of Asia and Indonesia, Australia, Eastern Europe, the eastern third of Africa, and the island nation of Madagascar.
When Venus is in transit across the solar disk, the planet appears as a distinct, albeit tiny, round black spot with a diameter just 1/32 of the Sun. This size is large enough to readily perceive with the naked eye: HOWEVER–prospective observers are warned to take special precautions (as with a solar eclipse) when attempting to view the silhouette of Venus against the blindingly brilliant disc of the Sun. The circumstances of the transits of Venus repeat themselves with great exactness after a period of 243 years. The intervals between individual transits (in years) currently go as follows: 8 + 121Ë† + 8 + 105Ë† = 243. In other words, a pair of transits will occur over a time span of just eight years, but following the second transit, the next will not occur again for over a century. The upcoming Venus transit of June 5—6, 2012 is the second of a pair, the first having occurred on June 8, 2004. Should clouds prevent you from getting a view of this year’s event, it will be most unfortunate, since the next opportunity to observe a transit of Venus will not occur again until December 10—11, 2117
Geocentric Circumstances of the Transit
Ingress exterior contact: 6:10 p.m. – Ingress interior contact: 6:28 p.m. Least angular distance from the Sun’s center: 9:30 p.m. – Egress interior contact: 12:32 a.m. (June 6) – Egress exterior contact: 12:50 a.m. (June 6) Least angular distance from the center of the Sun to Venus: 9.2 arc minutes