The Brightest Planets in June’s Night Sky: How to See them (and When)
In June, planet-wise, three out of five isn’t bad. In the evening sky, we need only look south at nightfall to view Jupiter, while rising in the east-southeast is the ringed wonder, Saturn, which arrives at opposition to the sun in the middle of the month and pretty much is visible in our sky from dusk to dawn all month long. The third planet is brilliant Venus, which is very evident during the dawn’s early light low in the eastern sky. The planets Mercury and Mars are both too close to the sun all month long to be seen.
In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm’s length measures roughly 10 degrees. Read on below for our schedule of the best planet-viewing times, as well directing you as to where to look to see them. [Stargazing Maps for the June Night Sky]
Passes through superior conjunction on the far side of the sun on the first day of summer (June 21). In July, this rocky little world will emerge from the sun’s glare to move into the evening sky.
Rises only about 2.5 hours before the sun this month and attains greatest western elongation on June 3 (46 degrees west of the sun), but remarkably, it won’t be highest at dawn for observers at mid-northern latitudes until early August.
Venus is visible about 10 degrees above the eastern horizon an hour before sunrise at the beginning of June, increasing to 20 degrees up by month’s end. By geometry it should now appear to be half-lit, but it may not look that way in a telescope until several dawns later. This effect was first noticed by the German amateur Johann Schröter.
On which day, a few days after greatest elongation, does the phase of Venus look exactly half in your telescope? Watch Venus slowly shrink from a fat crescent on June 1 to an 8-percent smaller gibbous disk on June 30. A waning crescent moon lies far to the right of dazzling Venus on the morning of June 20. By the following morning, the moon will have moved well down to the lower left of Venus.
Lastly, if you have binoculars, look less than 2 degrees to Venus’ upper left on June 3 and you’ll see a tiny 6th-magnitude “star” with a greenish-blue hue. That’s not a star, however, but the seventh planet out from the sun, Uranus.
Starts off the month setting just over an hour after the sun, but the combination of bright twilight, low altitude and the fact that the planet has now dimmed to second magnitude makes it all but well-nigh impossible to see in our evening sky. It is moving toward conjunction with the sun on July 27, and will be pretty much on a summer sabbatical, likely not becoming observable again until sometime during the latter part of September.
The first planet to appear as the sky darkens, shines prominently, high in the south-southwest, and appearing about 2 degrees below and a bit to the right of the waxing gibbous moon on June 3. The planet, which is currently a fine target in telescopes, does not set until well after midnight. As the Earth speeds around its orbit, we are leaving Jupiter far behind, which is why it appears not quite as bright as it did when it was at opposition to the sun in early April. Jupiter halts its retrograde (westward) motion and starts heading back toward Spica, nearly a dozen degrees to its left (east).
Is the best planet in June by virtue of its arrival at opposition on June 15. By late twilight, Saturn is already up in the southeast, inviting telescopes to be turned its way. To many observers the ringed planet is the crown jewel of the night sky, a judgement supported by the gasps of the non-astronomical public taking a first look at it through a telescope. On June 9, you’ll find it glowing to the lower right of the farthest full moon of 2017.