Skywatchers can expect an extraordinary celestial show over the next 24 hours, and possibly longer, as five planets form a “planet parade” in the morning sky on June 17. Early risers gazing skyward in the northern hemisphere may observe a quintet of planets—Saturn, Neptune, Jupiter, Uranus, and Mercury—forming a somewhat ragged ascending arc across a 93-degree sector of pre-dawn sky.
To catch this heavenly procession of planets—“planetary alignment” is the technical term—viewers will need to rise at least an hour before sunrise. Ideally, spectators should find a vantage point shrouded in darkness with minimal or no light pollution; and, preferably, a clear horizon devoid of trees, buildings, or other vertical obstructions, as Mercury will linger low near the horizon. As the new moon falls on June 18, naturally dark conditions are favorable for planet spotting, though with summer solstice right on the brink, nights are nearing their shortest for the year.
So, looking toward the northeast, one may behold the cosmic showstopper as it unfolds thusly:
The first to rise will be Saturn, which will appear around the middle of the night on June 16, your local time, or in the wee hours of June 17. One can find it in the constellation Aquarius and, with a stellar magnitude (measuring brightness) of 0.9, the planet will be visible to the naked eye.
Third in the procession will be Jupiter. The brightest celestial object in the sky, besides the sun and moon, this planet will shine brilliantly with a magnitude of -2.2. It will be easy to spot Jupiter with the naked eye, and it can be found in the constellation Aries.
Fourth, Uranus will make its low-key entrance with a muted magnitude of 5.8. One may try to spot Uranus 7 degrees below Jupiter in Aries also, however it is unlikely to be detected without a pair of binoculars at a minimum.
Fifth and last in the lineup, Mercury, the planet closest to our sun, will join in the rendezvous about an hour before sunrise, your local time. It might be a challenge to see it without a clear view of the horizon, particularly when viewing from higher latitudes. It will shine with a magnitude of -0.9 and will appear in the constellation Taurus, forming the tail-end of the planet parade.
- An astronomical event when planets gather closely on one side of the sun at the same time, as seen from above the solar system; or
- A visual phenomenon when the planets appear close together in a small sky sector, as seen from the Earth.
- Mini planetary alignment: 3 planets;
- Small planetary alignment: 4 planets;
- Large planetary alignment: 5 or 6 planets;
- Great (full) planetary alignment: 7 planets (+ Pluto sometimes).