Sky at a Glance May 5 – 12

Photo showing the location and description of the constellation Hercules in the eastern spring sky.

This Week’s Sky at a Glance, May 5 – 12 ~by Curt Nason

I was fascinated by the movie Hercules, starring bodybuilder Steve Reeves, which I saw one Saturday afternoon at the Vogue theatre in McAdam sometime in the early 60s. I was nurturing my interest in the sky at that time so the constellation of Hercules has long been a part of my life. These spring evenings it is in the east as twilight fades.

Look for a keystone asterism one third of the way from the bright star Vega toward equally bright Arcturus; that is the upside-down body of the legendary strongman. Hercules is usually depicted down on his right knee, with his left foot on the head of Draco the Dragon and his head close to that of Ophiuchus. Originally the constellation was called The Kneeler, and the star at his head is called Rasalgethi for “head of the kneeler.” It is the alpha star of the constellation, although Kornephoros (the club bearer) is brighter. The “head star” of Ophiuchus is called Rasalhague.

With binoculars you can pick out two globular clusters from the Messier catalogue in Hercules. Globular clusters are ancient compact groups of typically tens-to-hundreds of thousands of stars that orbit our galaxy’s core. One third of the way from the top right star of the Keystone to the bottom right star is M13, the finest globular cluster in the northern hemisphere. A line from the bottom right star through the middle of the top of the Keystone, and extended about an equal distance, will put you in the area of M92, one of the oldest objects in our area of the galaxy at more than 13 billion years.

This Week in the Solar System

Saturday’s sunrise in Moncton is at 5:59 am and sunset will occur at 8:32 pm, giving 14 hours, 33 minutes of daylight (6:07 am and 8:35 pm in Saint John). Next Saturday the Sun will rise at 5:50 am and set at 8:41 pm, giving 14 hours, 51 minutes of daylight (5:57 am and 8:43 pm in Saint John).

The Moon is near Mars on Sunday morning and is at third quarter on Monday. Jupiter takes the solar system spotlight this week, reaching opposition on Tuesday evening when it rises at sunset. A small scope will show its moon Io disappearing behind the planet shortly after 9 pm that evening and emerging from the other side two hours and ten minutes later. Venus balances Jupiter’s rise by outshining it in the west. Mercury might be spotted with binoculars and luck a half hour before sunrise. Saturn and Mars offer great viewing in the morning sky, with Mars brightening every week. The Eta Aquariid meteor shower, one of two showers arising from Halley’s Comet, peaks this weekend although it is seen better from the southern hemisphere.

The Saint John Astronomy Club meets in the Rockwood Park Interpretation Centre this Saturday at 7 pm, and the William Brydone Jack Astronomy Club meets in the UNB Forestry / Earth Sciences building in Fredericton on Tuesday at 7 pm. All are welcome.

Questions? Contact Curt Nason.

Leave a Reply

Your email address will not be published. Required fields are marked *