I know this weather is enough to discourage even the hardiest of sky observers from venturing out, but when the wind and snow do stop blowing long enough for a clear, still night, there is lots to look for in April.
As darkness falls this month, Jupiter pops into view high in the southwest sky, remaining visible until about 2 a.m. Shining at mag. -2.1, Jupiter is the brightest object in the evening sky. For those of you who have never seen any of Jupiter’s largest moons, this month presents a unique opportunity to spot three of them. At midnight on April 21, three of Jupiter’s largest moons — Io, Europa and Callisto — will be aligned in a straight line on the west (right-hand) side of Jupiter. Watch just shortly before midnight, as the three moons move into position, with Io sliding in between Europa and Callisto. This alignment will last only about 15 minutes.
Reaching opposition (directly opposite the sun in the sky) on April 8, Mars rises in the east near sunset and is at its highest point in the southern sky around 1 a.m. Shining at mag. -1.5 this month, Mars is the brightest it has been since 2007. The best time to view Mars this month is during the night/morning of April 14-15, when Mars makes its closest approach to Earth.
Saturn rises around 10:30 p.m. in the early part of April and about two hours earlier, during twilight, by month’s end. Best viewed after midnight, when highest in the night sky, Saturn’s magnificent ring system is tilted at a steep angle towards Earth this month, providing a great opportunity to see the rings’ structure.
As Saturn and Mars set in the west shortly before dawn, bright Venus heralds the approaching dawn, rising about two hours before the sun during the early part of April. By the end of the month, Venus languishes in her celestial bed somewhat longer, rising only about 20 minutes or so before sunrise. At mag. -4.3 this month, Venus shines as the brightest point of light in the sky before the sun makes its appearance.
This year there are four lunar eclipses, although, unfortunately, not all are visible from the Maritimes. However, the first one, a total lunar eclipse, is. In the post-midnight hours of April 15, the moon will pass through the Earth’s shadow in space, darkening to a reddish-orange colour. Earth’s shadow in space has a bull’s eye target configuration of two concentric shadows. The outer shadow, known as the penumbral shadow is not as dark as the inner umbral shadow. First contact (with the penumbral shadow) starts at 2:58 a.m.. You will only see a very faint darkening of the moon’s surface as it passes into the penumbral shadow. Totality, when the moon slides into the umbral shadow and really starts to darken and take on a noticeable reddish-orange tone, commences at 4:07 a.m., and lasts 78 minutes. By about 5:30 a.m., the moon’s disc begins to brighten again. For more information on this unique celestial event, go to www.astronomy.com or www.skyandtelescope.com or simple Google April 2014 lunar eclipse.
Unfortunately, this month’s Lyrid meteor shower (radiant in Lyra — the Harp) which peaks during the pre-dawn hours of April 22 will be hindered by the last quarter moon which rises about 2 a.m. The best time to catch a glimpse of the lyrids will be in the two-hour period before moonrise.
April’s full moon on April 15 is often referred to the Grass Moon, as this is the time of year when the grass is (usually) free of the snow and begins to show green. Though we may not see the grass here on P.E.I. until some time in June, we can, at least, honour April’s full moon as a true symbol of spring (whenever it arrives).
Until next month, clear skies.
April 7 – First quarter moon, 5:31 a.m.;
April 8 – Mars at 2014 peak mag. -1.5;
April 14 – Mars closest to Earth, 91.8 million kms.,10:00 a.m.;
April 15 – Full (Grass) moon; 4:42 a.m.; total lunar eclipse (pre-dawn);
April 22 – Last quarter moon, 4:52 a.m.; Lyrid meteor shower peaks (pre-dawn); moon at perigee (closest to Earth), 367,618 kms., 9:24 p.m.
Glenn K. Roberts is a member of the Charlottetown Centre of the Royal Astronomical Society of Canada (RASC). His column appears in The Guardian once a month. He welcomes comments from readers. Anyone who would like to comment on his column is encouraged to email him at firstname.lastname@example.org.