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 24 – Very old moon meets Mercury (before sunrise)
Just above the eastern horizon before sunrise on Monday, October 24, the very old crescent moon (only one per cent illuminated) will shine less than a thumb’s width above (or 1.6 degrees to the northwest of) the bright planet Mercury. The duo will be tough to see within the pre-dawn twilight. Binoculars (green circle) will help your search — but be sure to turn them away before the sun rises. The optimal viewing window at mid-northern latitudes will be 6:30 p.m. to 6:50 a.m. local time.
Tuesday, October 25 – New Moon and partial solar eclipse (at 10:49 GMT)
The moon will officially reach its new phase at 6:49 a.m. EDT, 3:49 a.m. PDT, or 10:49 GMT on Tuesday, October 25. This new moon will also feature a deep partial solar eclipse that will be visible across most of Europe, northeastern Africa and the Middle East, and central Asia.
After the moon’s penumbral shadow first contacts Earth in the North Atlantic Ocean around sunrise at 08:58:20 GMT, it will sweep eastward and south across Europe and the Middle East until it lifts off Earth near the Persian Gulf at 13:02:16 GMT.
The instant of greatest eclipse, with the moon blocking 0.63 of the sun’s diameter, will occur east of Surgut, Russia — around sunset, at 11:01:20 GMT. This solar eclipse will be followed by a total lunar eclipse on November 8. Protective solar filters will be needed to view any part of this eclipse.
Wednesday, October 26 – Double shadow transit on Jupiter (20:20 to 22:20 GMT)
On Wednesday evening, October 26, observers with telescopes across Africa, Europe, and western Asia can watch the round black shadows of two of Jupiter’s moons cross the southern hemisphere of the giant planet together for two hours. At 10:20 p.m. CEST or 20:20 GMT, the large shadow of Ganymede will join Europa’s smaller shadow, which begins to cross at 9:55 p.m. CEST. Europa’s shadow will move off Jupiter at 12:20 a.m. CEST or 22:20 GMT, leaving Ganymede’s shadow to cross alone until 1:00 a.m. CEST or 23:00 GMT.
Thursday, October 27 – Young Moon near Antares (after sunset)
Low in the southwestern sky after dusk on Thursday, October 27, the young crescent moon will shine beside the claw stars of Scorpius, several finger widths to the right (or four degrees to the celestial northwest) of the scorpion’s bright, reddish star Antares. They will be close enough to share the view in binoculars (green circle). Scorpius’ stars will become easier to see as the sky darkens, but the tableau will disappear below the rooftops by about 7 p.m. local time.
Saturday, October 29 – Mars enters retrograde (overnight)
On Saturday night, October 29 in the Americas, Mars’ eastward prograde motion through the stars of Taurus will slow to a stop in order for it to begin a westerly retrograde loop that will last through its December opposition, and into mid-January. On Saturday evening, bright, reddish Mars will be positioned in the eastern sky between the two horn tips of the bull — the medium-bright stars Zeta Tauri and Elnath. Over the next month, stargazers can watch Mars swing between those stars and then race west (red path with date:hr) towards the bright Pleiades star cluster.
Sunday, October 30 – Medusa’s eye pulses (at 01:39 GMT)
In the constellation of Perseus, Algol, also designated Beta Persei, marks the glowing eye of Medusa from Greek mythology. The star is among the most accessible variable stars for skywatchers.
During a 10-hour period that repeats every two days, 20 hours, and 49 minutes, Algol dims noticeably and re-brightens, because a companion star orbiting nearly edge-on to Earth crosses in front of the much brighter main star, reducing the total light output we perceive.
Algol normally shines at magnitude 2.1, similar to nearby Almach in Andromeda. But when fully dimmed, Algol’s magnitude 3.4 is slightly fainter than Rho Persei (ρ Per), the star sitting just two finger widths to Algol’s lower right (or 2.25 degrees to the celestial south).
On Sunday, October 30 at 9:39 p.m. EDT or 6:39 p.m. PDT, Algol will be at its minimum brightness. At that time it will be located in the lower part of the northeastern sky. Five hours later, the star will return to full intensity from a perch nearly overhead.