Every week, SkyNews publishes a list of key events in the Canadian sky in This Week’s Sky. This series gives you all the latest news in Solar System movements, including where the planets are in our sky and Moon phases. From eclipses to meteor showers, This Week’s Sky keeps you updated on the best in upcoming astronomical highlights.
Monday, October 31 – The spooky Owl Cluster (all night)
One of my favourite spooky objects can be seen in binoculars or a backyard telescope on autumn evenings. It is one of the many bright, open star clusters in the W-shaped of Cassiopeia (the Queen), which you will find in the northeastern sky.
NGC 457, better known as the Owl Cluster, ET Cluster, or Dragonfly Cluster, is dominated by two prominent, close-together, yellow stars (Phi Cas and HD 7902) that form the eyes — a sprinkling of dimmer stars for the body and feet, and two curved chains of stars that look like upswept wings. Be aware that the critter is positioned with its head pointing away from Cassiopeia, which circles the north celestial pole.
The cluster occupies the 90 degree corner of a right-angle triangle that is completed by the stars Gamma Cas and Ruchbah. It is about two finger-widths above (or two degrees to the celestial south-southwest of) Ruchbah — as if the queen is bouncing the baby owl on her knee!
Tuesday, November 1 – First quarter Moon (at 06:37 GMT)
The Moon will complete the first quarter of its 29.53-day journey around Earth on Tuesday, November 1 at 2:37 a.m. EDT, 12:37 a.m. MDT, and 06:37 GMT.
At first quarter, the Moon’s 90 degree angle from the Sun causes us to see it half-illuminated, on its eastern side. At first quarter, the Moon always rises around midday and sets around midnight, so it is also visible in the afternoon daytime sky.
The evenings surrounding the first quarter are the best ones for seeing the lunar terrain when it is dramatically lit by low-angle sunlight — especially along the terminator (the pole-to-pole boundary that separates the Moon’s lit and dark hemispheres).
Tuesday, November 1 – Half Moon near Saturn (evening)
After the Moon rises in the Americas in the late afternoon on Tuesday, November 1, it will be slightly more than half-illuminated and shining several finger-widths below Saturn in Capricornus — close enough for them to share the view in binoculars (green circle). By the time the duo sets around midnight, the diurnal rotation of the sky will shift Saturn lower, to the Moon’s right.
Wednesday, November 2 – Watch Algol brighten (at 22:28 GMT)
The star Algol (or Beta Persei) in the constellation of Perseus is among the most easy-to-monitor variable stars.
During a 10-hour period that repeats every two days, 20 hours, and 49 minutes, Algol dims noticeably, and then re-brightens when a companion star (with an orbit nearly edge-on to Earth) crosses in front of the much brighter main star. This in turn reduced the total light output we perceive.
Algol normally shines at magnitude 2.1, similar to the nearby star Almach in Andromeda. But while dimmed to minimum brightness, Algol’s magnitude 3.4 is almost the same as the star Rho Persei (ρ Per), which sits just two finger-widths to Algol’s lower right (or 2.25 degrees to the celestial south).
For observers in eastern North America, fully dimmed Algol will sit in the lower part of the east-northeastern sky on Wednesday, November 2 at 6:28 p.m. EDT or 22:28 GMT. Five hours later, the star will shine at full intensity from a perch high in the eastern sky. Observers in more westerly time zones can see the latter stages of the brightening.
Wednesday, November 2 – Two shadows cross Jupiter (8:25 p.m. to 8:57 p.m. EDT)
From time to time, observers with good telescopes can watch the small, round black shadows of the Galilean moons traverse Jupiter’s disk. On Wednesday evening, November 2, sky-watchers located east of Calgary, Alberta, and Phoenix, Arizona, can watch two shadows crossing the southern hemisphere of Jupiter at the same time, for about half an hour.
At 8:25 p.m. EDT (or 00:25 GMT on Nov 3), the large shadow of Ganymede will join the small shadow of Europa, which began its own crossing of the planet two hours earlier. Europa’s shadow will leave Jupiter at 8:57 p.m. EDT (or 00:57 GMT), leaving Ganymede’s shadow to continue on alone until 11 p.m. EDT (or 03:00 GMT).
Friday, November 4 – Gibbous Moon visits Jupiter and Neptune (evening)
On Friday night, November 4, the bright, gibbous Moon will shine several finger widths below (or three degrees to the celestial south of) Jupiter — close enough for them to share the view in binoculars (green circle). As the pair slides west during the night, the diurnal rotation of the sky will lift the Moon to Jupiter’s upper left. Meanwhile, the faint, blue planet Neptune will be positioned a palm’s width to the right (celestial west-southwest) of Jupiter during the evening. The bright Moon will make seeing Neptune harder, so wait for a night when the Moon has left that part of the sky.
Saturday, November 5 – Southern Taurids meteor shower peak (wee hours)
The Southern Taurids shower, which runs worldwide from September 28 to December 2 annually, will reach its maximum rate of about five meteors per hour on the afternoon of Saturday, November 5. Since meteors require a dark sky, the best viewing time in the Americas will be before dawn on Saturday morning and on Saturday night, although somewhat fewer meteors will be seen.
The long-lasting, weak shower is the first of two consecutive showers derived from debris dropped by the passage of periodic Comet 2P/Encke. The larger-than-average grain sizes of the comet’s debris often produce colourful fireballs. Unfortunately, the Moon will be nearly full at this year’s peak. More meteors might be revealed once the bright Moon sets an hour before dawn.
Sunday, November 6 – The Moon’s western region (all night)
The left-hand (western) half of the Moon’s Earth-facing hemisphere is dominated by the large and irregular Oceanus Procellarum (“the Ocean of Storms”) and round Mare Imbrium (“the Sea of Rains”), which adjoins Procellarum to the lunar northeast.
Both are ancient basins that were excavated by huge impactors and later flooded with dark, iron-rich basalts that upwelled from the Moon’s interior. The lunar maria are far less cratered than the bright highlands, but they are not featureless. Binoculars and telescope views reveal that the basalts vary in colour and darkness, due to their chemistry. When the lunar terminator is near a mare, slanted sunlight casts shadows from curved wrinkle ridges that ring each mare’s interior.
