This Week’s Sky at a Glance, 2022 June 25 – July 2
~by Curt Nason
Arrows are used in signs as pointers to direct us to notable sites. As the Summer Triangle of the bright stars Vega, Deneb and Altair rise high in late evening, the tiny constellation of Sagitta the Arrow can direct us to a few interesting binocular objects. Sagitta is a compact arrow situated halfway between Altair and Albireo, which form the heads of Aquila the Eagle and Cygnus the Swan. Albireo itself is an interesting binocular object, being revealed as two colourful stars.
Looking under the shaft of the arrow with binoculars you might notice a hazy patch of stars called M71, which is a globular cluster containing more than 10,000 stars. As globular clusters go it is younger than most and relatively small. Half a binocular field above the arrowhead is ghostly M27, the Dumbbell Nebula. This is a planetary nebula; gases emitted from a Sun-sized star as its nuclear fuel was running out. The star collapsed into a hot, dense Earth-sized star called a white dwarf, and the ultraviolet radiation emitted from it causes the gases to glow. In older photographs of M27 its bipolar shape resembled a dumbbell. About a binocular width to the upper right of the arrow’s fletching is an asterism called the Coathanger, a favourite treat for closet astronomers.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:29 am and sunset will occur at 9:14 pm, giving 15 hours, 45 minutes of daylight (5:37 am and 9:16 pm in Saint John). Next Saturday the Sun will rise at 5:32 am and set at 9:13 pm, giving 15 hours, 41 minutes of daylight (5:40 am and 9:15 pm in Saint John).
The Moon completes its planetary line-up tour this week, with the slim waning crescent visiting Venus on Sunday and Mercury on Monday before disappearing on Tuesday. Don’t worry about the disappearance, it’s just a new phase it’s going through. Try the binocular challenge of spotting the razor-thin crescent in the west-northwest after sunset on Wednesday when it is less than a day old. The planets continue to increase their spatial distancing over the week.
On Sunday evening at 8 pm, tune in to the Sunday Night Astronomy Show via the Facebook page or YouTube channel of Astronomy by the Bay.
Questions? Contact Curt Nason.