Summer is finally here. Already we have experienced the summer solstice, and this hemisphere’s longest day.
Though we will not notice it for another month or so, the nights are slowly getting longer. The prospect of warmer weather will, hopefully, encourage people to linger outdoors during the evening and early night to gaze at the heavens above.
Just as darkness falls, Mars (mag. 0.0) appears in the southwest sky, remaining visible until midnight or later. This is the best time to view our near-neighbour, when it is at its highest point in the night sky. On the evening of July 5, the first quarter moon sits close to Mars. On July 12, the Red Planet makes a close conjunction with the bright star, Spica, in the constellation of Virgo – the Maiden.
As a point of interest, Spica is the 15th brightest star in the night sky. Notice the stunning contrast between the reddish-orange hue of Mars and the blue-white colour of Spica. Mars shines a full magnitude (a factor of 2.5x) brighter than Spica. This conjunction is best viewed in binoculars or a low-power scope.
While you are looking at the conjunction of Mars and Spica that evening, swing the binoculars or scope to the upper left (approx. 10 o’clock position) to view Saturn. Sitting about 30 degrees (three fists’ widths) above the SW horizon in the constellation of Libra – the Balance as twilight fades, and shining at mag. -0.4, this golden-coloured planet is a magnificent sight in both binoculars and a scope.
In July, Saturn’s beautiful ring system is tilted 21 degrees towards our line of sight, affording an excellent opportunity to view this unique celestial wonder. Saturn is slowly moving towards Mars in the evening sky, heading for their closest approach to one another in late August.
If you notice another bright reddish star to the lower left of Saturn, you will have found the star Antares, the heart star of Scorpius – the Scorpion. Antares means rival of Mars, due to its very obvious red colour.
Moving now to the pre-dawn sky, Venus (mag. -3.8), our morning star, rises in the E as morning twilight first lightens the eastern horizon. You will have no problem identifying Venus, as it is the brightest object in that area of the sky.
Mercury makes a brief appearance on the celestial stage this month during the pre-dawn twilight. On the morning of July 12, Mercury is at its greatest eastern elongation (angular distance from the Sun, as viewed from Earth), sitting almost a hand’s width above the ENE horizon, about 45 minutes before sunrise. On July 15th, look to the ENE about 30 minutes before sunrise to see Mercury below Venus.
July’s southern Delta Aquarid (radiant in Aquarius – the Water Bearer) meteor shower actually appears from July 12 through Aug. 23. However, the shower’s peak itself arrives this year on July 30. The peak intensity of this shower has been known to last a few days, so watch the morning of July 29 and 31.
As with most meteor showers, the Delta Aquarids are best viewed in the pre-dawn hours leading up to morning twilight. Expect to see approximately 15 to 20 bright meteors emanating from the south during the peak of the shower.
The waxing, crescent moon will be gone from the sky late in July, so will not interfere with viewing the meteor show.
As mentioned last month, Comet K1 (PANSTARRS C/2012) is expected to reach mag. 7 or 8 in July, bringing it easily within view of binoculars and telescopes. However, you will have to look for the comet during the first half of the month (first week is the best), as the moon will interfere with the view in the second half of July. Start looking for Comet K1 about two hours after sunset, when it will sit about 10 degrees (a hand’s width at arm’s length) in the WNW part of the sky. The further you can get away from city lights, the darker the sky will be, and the better your chances of finding the comet.
Look for the sickle-shaped asterism that forms the head of Leo - the Lion constellation, and then locate the two end stars of the sickle’s blade. Comet K1 will track to the SSW along a path that runs parallel to an imaginary line drawn between these two stars. Under a dark sky and good seeing conditions, you should be able to spot the comet’s two tails - one, the gas tail, flowing to the E, directly away from the Sun; the other, the dust tail, curving away from Earth. If the seeing is particularly good, you might even seethe bright nucleus in the comet’s coma.
July’s full moon is sometimes referred to as the “hay moon” as July is usually the month when farmers harvest their first crop of hay.
Until next month, clear skies.
July 3 - Earth at aphelion (furthest from the sun); 151.2 million kms; 9:00 p.m.;
July 5 – First quarter moon; 8:59 a.m.;
July 12 – Full (“hay”) moon; 8:25 a.m.;
July 13 – Moon at perigee (closest to Earth); 356,180 kms; 5:26 a.m.;
July 18 – Last quarter moon; 11:08 p.m.;
July 26 – New moon; 7:42 p.m.;
July 28 – Moon at apogee (furthest from Earth); 404,206 kms; 12:28 a.m.;
July 30 – S.Delta Aquarid meteor shower peaks; pre-dawn
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 email@example.com.