TAWBAS star party

This Week’s Sky: May 14 – 21

The crescent Moon checks in with Venus and Regulus.


The evening sky features many fine globular star clusters, including M5, in Serpens. Courtesy Ron Brecher

All Week

The view facing south at the start of morning twilight

The view facing south at the start of morning twilight.

The evening sky right now is a tale of two worlds—one a naked-eye spectacle, the other a telescopic wonder. The “spectacle” is magnitude –3.9 Venus, which can be spotted in the west shortly after sunset. The dazzling evening “star” is in the midst of an apparition that will last through October. At magnitude –2.5, Jupiter is, of course, no slouch as a naked-eye sight, but it’s in a telescope that the gas giant really shines. Currently just past opposition, Jupiter offers planetary observers a detail-laden disc almost 45 arc seconds across. With its Great Red Spot, numerous cloud belts, and quartet of bright moons, Jupiter always offers something to see. The best telescopic views are had when Big Jove is near the meridian, which happens this week about half an hour after midnight, local daylight time. The predawn also has its share of planetary attractions, with Saturn and Mars. Saturn shines at magnitude 0.3, rises at midnight, and culminates around 4:20 a.m. Mars clears the southeastern horizon a little before 1:30 a.m., and is still gaining altitude as dawn breaks. The red planet is a magnitude –0.8 object with a disc spanning 13 arc seconds—approximately half the size it will attain at the end of July.

May 15

The Moon is new today at 7:48 a.m., EDT.

May 17

the view facing west-northwest, 45 minutes after sunset

The view facing west-northwest, 45 minutes after sunset.

Look to the west after sunset to see a thin crescent Moon paired with brilliant Venus. These conjunctions are always eye-catching, even when the objects aren’t especially close. This evening, the lunar disc is situated a little more than 6 degrees from the planet during twilight, as seen from central Canada. On the West Coast, the twosome will be one degree farther apart at dusk.

May 21

The Moon and Regulus as seen in a small telescope at low power

The Moon and Regulus as seen in a small telescope at low power. The field of view shown is 1 degree.

The Moon reaches first-quarter phase just before midnight (11:49 p.m., EDT) and is positioned slightly north of 1.4-magnitude Regulus, the brightest star in Leo. The Moon will drift to within ½ degree of Regulus at about 10:45 p.m—close enough for both objects to appear together in a telescope used at low power.

Weekend Stargazer

M5 Chart

Use this chart to locate globular cluster, M5. (Click on the image for a full-size version.)

The waxing crescent Moon puts some light into the evening sky over the May 18 – 20 weekend, but if you wait until 11 p.m. or so, it’ll cease to be much of a factor. However, a little moonlight shouldn’t stop you from enjoying bright deep-sky targets. One that’s currently well positioned for late evening viewing is globular cluster M5, in the constellation Serpens Caput.

Locating M5 is a straightforward affair if you picture it as the westernmost point in an equilateral triangle that also includes the stars Alpha (α) and Mu (μ) Serpentis. Although not as famous as M13, in Hercules, M5 is actually a touch brighter—magnitude 5.7 versus 5.8. Indeed, M5 holds the distinction of being the brightest globular cluster in the northern sky! The Serpens cluster is, unsurprisingly, an easy binocular target, though the low magnification typical of binos makes all but a few globulars appear nearly stellar. Thankfully, M5 is conveniently parked next to a similarly bright star—5th-magnitude 5 Serpentis. The ready comparison makes the slightly fuzzy nature of the globular more obvious.

In a telescope M5 is a splendid sight—and the greater the aperture, the better the view. Although small instruments do a fine job with the globular, it’s hard to beat the light-gathering and resolution capabilities of a big scope. The most memorable view I’ve ever had of M5 was with a friend’s 17.5-inch Dob. The cluster was simply stunning, its luminous, tightly packed central knot enveloped in a spherical swarm of faint stars. Beautiful.

At SkyNews we love to read about your experiences and see your photos. You can share them with us by e-mailing [email protected].

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