This Week’s Sky at a Glance, 2023 Sept. 2 – Sept. 9
This Week’s Sky at a Glance, 2023 Sept. 2 – Sept. 9
The constellation Capricornus is a large chevron shape that is south-southeast around 10 pm this week. A pair of stars marks each upper corner, and both stars of the western pair are colourful wide double stars. The sea goat arises from a tale of the Olympian gods being surprised by Typhon, the most ferocious of the rival Titans. Knowing Typhon was not fond of water, the gods changed into fish and escaped to the sea. The god Pan, who was half-goat and half-man, panicked and dove in before the transformation was complete and wound up with a goat’s head and the tail of a fish.
There are four common targets for backyard telescope users near Capricornus, but only the globular cluster M30 off the east side of the chevron is officially within its borders. It is also the easiest of the targets for binoculars. The globular cluster M72 and the four-star (literally four stars, it is not an observing highlight) asterism M73 are above in Aquarius. Nearby is the more challenging, but worth the effort, Saturn Nebula (NGC7009), the gaseous remnant of a dead star that somewhat resembles the ringed planet.
A few millennia ago the Sun was in Capricornus at the winter solstice, when at midday it was overhead for latitude -23.5 degrees. This is the southern border of the tropics, and it is still called the Tropic of Capricorn despite the Sun now being in Sagittarius at the beginning of winter. Earth’s 25,800-year polar wobble, called the precession of the equinox, is responsible for this shift.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:40 am and sunset will occur at 7:56 pm, giving 13 hours, 16 minutes of daylight (6:46 am and 8:00 pm in Saint John). Next Saturday the Sun will rise at 6:49 am and set at 7:42 pm, giving 12 hours, 53 minutes of daylight (6:55 am and 7:47 pm in Saint John).
The Moon rises to the left of Jupiter around 10:15 Monday evening and it reaches third quarter phase on Wednesday. Jupiter is stationary on Monday, after which it begins four months of retrograde motion relative to the stars. Saturn is now rising before sunset and is at its highest for best observing around midnight. Mercury is at inferior conjunction on Wednesday, moving quickly into the morning sky and rising an hour before the Sun a week later. Mars is too close to the setting Sun for viewing. Venus, once called Lucifer the Morning Star, trails the bright winter stars into the early morning sky while outshining them all.
The Saint John Astronomy Club meets at the Rockwood Park Interpretation Centre on September 2 at 7 pm. The RASC NB star party at Fundy National Park is on for next weekend, September 8 – 9. For more information: https://rascnb.ca/event/fundy-stargaze/