Advanced VX Computerized Telescopes

This Week’s Sky: May 2 – 9

The Moon is new and Mercury transits the Sun.

SOHO Mercury transit

The last time Mercury crossed the Sun was November 2006 — an event recorded from space by the SOHO satellite. Courtesy NASA

All Week

South, 45min after sunset

The view facing south, 45 minutes after sunset.

With the nights rapidly growing shorter, time is starting to wind down on the Jupiter observing season. The planet is already past the meridian before the end of twilight, so don’t let clear nights pass you by. Thankfully, while Jupiter starts to decline, Mars is approaching its prime. The red planet rises as astronomical twilight ends — a little before 10:30 p.m., local daylight time. The best time to view Mars, though, is around 2 a.m., when it’s near the meridian. The planet shines at magnitude –1.6 and spans nearly 17 arc seconds — only 2 arc seconds shy of the maximum it will reach at the end of May. (For more on observing Mars, turn to page 33 of the current issue of SkyNews.) Last, but not least, is Saturn. It’s positioned near Mars and reaches the meridian at about 3:20 a.m. The ringed planet is an irresistible target for telescopes of all sizes.

May 5

Eta Aquarid radiant

Eta Aquarid meteors appear to radiate from Aquarius, in an area south of Pegasus. This is the view facing east-southeast at 4 a.m., local daylight time.

This morning the Eta Aquarid meteor shower peaks under near-ideal conditions with the Moon out of the picture. The display is one of the richest of the year, with a zenithal hourly rate (ZHR) of 60 meteors per hour. But that first word, “zenithal,” is the one to note. The radiant of the Eta Aquarids is nowhere near the zenith for observers at Canadian latitudes. That means the number of meteors you can expect to see, even under dark-sky conditions, is much less. Still, it’s worth getting up in the predawn hours of May 5 and 6 to catch as many Eta Aquarids as you can.

May 6

New Moon occurs at 3:30 p.m., EDT, today.

May 6/7

May 6/7 double-shadow transit

The May 6/7 double-shadow transit at the midway point.

Tonight is your last chance to see a double-shadow transit on Jupiter this apparition. Luckily, it’s visible all across the country, though the planet is lower in the sky the farther east you are situated. Events get underway at 9:39 p.m., PDT, May 6 (12:39 a.m., EDT, May 7) when Io’s shadow joins Callisto’s on the Jovian disc. At 10:42 p.m., PDT, May 6 (1:42 a.m., EDT, May 7) Callisto’s shadow leaves the planet and the event wraps up.

May 9

Mercury Transit

Mercury takes roughly 7½ hours to travel across the face of the Sun.

Today features a rare transit of Mercury. Given that it takes nearly 7½ hours for the little planet to cross the disc of the Sun, you have a pretty good chance of seeing at least part of the event even if the weather isn’t perfect. Mercury begins its transit at 7:13 a.m., EDT and reaches the halfway point at 10:58 a.m. The transit ends when Mercury edges off the Sun at 2:41 p.m., EDT. Observers in Manitoba and eastward will get to see the entire transit, while the rest of the country will see the Sun rise with the transit already underway. A small telescope fitted with a safe solar filter will show the planet as a tiny, round black dot on the solar disc. You don’t want to miss this. The next Mercury transit will come in 2019, but after that, you’ll have to wait until 2032.

For more detailed transit information, turn to page 26 of the current issue of SkyNews.

Weekend Stargazer

M3 finder

Globular cluster M3 lies along a line connecting the stars Arcturus and Cor Coroli.

Perhaps it’s a Canadian thing, but it seems stargazers spend a lot of time looking for the first signs of summer — especially after a long, difficult winter or wet, rainy spring. One sure signal that summer is just around the corner is the return of bright globular clusters to the evening sky. The May 6 – 8 weekend is moonless and provides a good opportunity to search out the first of these: M3. It leads the parade of impressive globulars that makes summer stargazing so rewarding. As darkness arrives, M3 is in prime position nearly overhead.

Although M3 resides in the constellation Canes Venatici, I always think of it as belonging to nearby Boötes. The easiest way to pin down M3 is to draw an imaginary line connecting the stars Arcturus and Cor Corali. M3 is situated a little less than half way from Arcturus. Shining at magnitude 6.2, the cluster is an easy catch in binoculars, which show it as a slightly bloated, fuzzy “star.” Small telescopes used at moderate magnification will start to resolve individual cluster members, and the view in a 8- or 10-inch scope can be spectacular.

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