New Moon on October 6, 2021. | SkyNews
New Moon on October 6, 2021 (Chris Vaughan, Starry Night Education)

This Week’s Sky: October 4 to 10, 2021

Look for deep-sky objects in dark skies this week with new Moon on Wednesday.

Monday, October 4 – Morning Zodiacal Light for mid-northern Observers (pre-dawn)

Morning zodiacal light for mid-northern observers on October 4, 2021. | SkyNews
Morning zodiacal light for mid-northern observers on October 4, 2021 (Chris Vaughan, Starry Night Education)

During autumn at mid-northern latitudes every year, the ecliptic extends nearly vertically upward from the eastern horizon before dawn. That geometry favours the appearance of the faint zodiacal light in the eastern sky for about half an hour before dawn on moonless mornings. Zodiacal light is sunlight scattered by interplanetary particles that are concentrated in the plane of the Solar System — the same material that produces meteor showers. It is more readily seen in areas free of urban light pollution. Between now until the full Moon on October 20, look for a broad wedge of faint light extending upwards from the eastern horizon and centred on the ecliptic (the green line). It will be strongest in the lower third of the sky, around the bright star Regulus. Try taking a long exposure photograph to capture it. Don’t confuse the zodiacal light with the Milky Way, which is positioned off to the south-southeast.

Wednesday, October 6 – New Moon (at 11:05 GMT)

New Moon on October 6, 2021. | SkyNews
New Moon on October 6, 2021 (Chris Vaughan, Starry Night Education)

The Moon will reach its new phase on Wednesday, October 6 at 7:05 a.m. EDT or 11:05 GMT. While new, the Moon is travelling between Earth and the sun. Since sunlight can only reach the far side of the Moon, and the Moon is in the same region of the sky as the sun, the Moon becomes unobservable from anywhere on Earth for about a day (except during a solar eclipse). On the evenings following the new Moon phase, Earth’s planetary partner will return to shine in the western sky after sunset.

Friday, October 8 – Dwarf planet Ceres changes direction (overnight)

Dwarf planet Ceres changes direction on October 8, 2021. | SkyNews
Dwarf planet Ceres changes direction on October 8, 2021 (Chris Vaughan, Starry Night Education)

On Friday, October 8, the dwarf planet Ceres will cease its eastward motion across the stars of central Taurus. After tonight, Ceres will begin a westward retrograde loop (red path with dates:time) that will last until mid-January. In late evening, the magnitude 8.2 object will be located low in the eastern sky, several finger widths to the lower left (or 2.7 degrees to the celestial east) of the Bull’s brightest star Aldebaran.

Saturday, October 9 – Young Moon and Venus in Scorpius’ claws (after sunset)

Young Moon and Venus in Scorpius' claws on October 9, 2021. | SkyNews
Young Moon and Venus in Scorpius’ claws on October 9, 2021 (Chris Vaughan, Starry Night Education)

As the sky darkens after sunset on Saturday, October 9, watch the southwestern sky for the pairing of the slim crescent Moon shining just above (or 2 degrees to the celestial north of) very bright Venus – easily close enough for them to share your binoculars’ field of view. Sharp-eyed skywatchers who can spot the Moon in late afternoon can also try to see Venus’ bright speck below it in daytime, even without binoculars! Once the sky darkens, after about 7:30 p.m. in your local time zone, the fainter claw stars of Scorpius will appear around the Moon and Venus.

Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the universe together.

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