A diagram of the third quarter Moon on June 2, 2021. | Astronomy news & night sky events | SkyNews
Third quarter Moon (Chris Vaughan, Starry Night Education)

This Week’s Sky: May 31 to June 6, 2021

The Moon reaches third quarter this week after meeting up with Saturn and Jupiter pre-dawn.

Monday, May 31 – Gibbous Moon near Saturn and Jupiter (pre-dawn)

A diagram of the gibbous Moon near Saturn and Jupiter, pre-dawn, on May 31, 2021. | Astronomy news & night sky events | SkyNews
Gibbous Moon near Saturn and Jupiter, pre-dawn (Chris Vaughan, Starry Night Education)

When the waning gibbous Moon rises about an hour after midnight on Monday morning, May 31, it will be positioned less than a palm’s width below (or five degrees to the celestial south of) Saturn. Jupiter will be shining brightly off to the pair’s left. By sunrise, the trio will be in the lower part of the southern sky, making a lovely photo opportunity when composed with some interesting foreground scenery.

Tuesday, June 1 – Half-Moon below Jupiter (pre-dawn)

A diagram of the Half-Moon below Jupiter (pre-dawn) on June 1, 2021. | Astronomy news & night sky events | SkyNews
Half-Moon below Jupiter, pre-dawn (Chris Vaughan, Starry Night Education)

For several hours preceding sunrise on Tuesday, June 1 the waning, half-illuminated Moon will shine a slim palm’s width to the lower right (or 5 degrees to the celestial south) of the very bright planet Jupiter. The pair will just squeeze into the field of view of binoculars (red circle). Somewhat fainter Saturn will be positioned to the right (celestial west) of them. The trio will make a lovely wide field photograph when composed with some interesting landscape.

Wednesday, June 2 – Third quarter Moon (at 07:24 GMT)

A diagram of the third quarter Moon on June 2, 2021. | Astronomy news & night sky events | SkyNews
Third quarter Moon (Chris Vaughan, Starry Night Education)

The Moon will officially reach its third quarter phase at 3:24 a.m. EDT (or 7:24 GMT) on Wednesday, June 2. The name for this phase refers not to the Moon’s appearance – but to the fact that it has completed three quarters of its orbit around Earth, measuring from the previous new Moon. At third quarter our natural satellite always appears half-illuminated, on its western side – towards the pre-dawn sun. It rises in the middle of the night and remains visible in the southern sky all morning. The ensuing week of moonless evening skies will be ideal for observing deep sky targets.

Sunday, June 6 – Juno at opposition near Messier 10 (all night)

A diagram of Juno at opposition near Messier 10, all night on June 6, 2021. | Astronomy news & night sky events | SkyNews
Juno at opposition near Messier 10, all night (Chris Vaughan, Starry Night Education)

On Sunday, June 6, the major main belt asteroid designated (3) Juno will reach opposition. At that time, Earth will be passing between Juno and the sun, minimizing our distance from Juno and causing it to appear at its brightest and largest for this year. The magnitude 10.1 asteroid will be visible in backyard telescopes all night long. On opposition night, Juno will be traversing the stars of Ophiuchus, and positioned just two finger widths to the left (or 2.5 degrees to the celestial east) of the bright globular star cluster Messier 10. On June 17-18 Juno’s westward motion (red path with labeled date:time) will carry it through that cluster, allowing both objects to appear together in telescopes for several nights.

Monday, June 7 – Old Moon near Uranus (before sunrise)

A diagram of the old Moon near Uranus, before sunrise on June 7, 2021. | Astronomy news & night sky events | SkyNews
Old Moon near Uranus, before sunrise (Chris Vaughan, Starry Night Education)

Look low in the east-northeastern sky before dawn on Monday, June 7 to see the old crescent Moon shining three finger widths below (or 3 degrees to the celestial southeast) of the magnitude 5.9 planet Uranus – close enough for them to fit together in the field of view of binoculars (red circle). Observers viewing the duo from more southerly latitudes will see them more easily since they’ll be higher and in a darker sky.

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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