Meet the stars Antares and Aldebaran. Both are bright stars. Both are reddish stars. They reside in two different constellations, on opposite sides of the sky’s dome. Antares – the brightest star in the constellation Scorpius the Scorpion – stays out for most of the night on these June nights, and at nightfall, sits low in the southeast beneath the golden planet Saturn. Meanwhile, Aldebaran – brightest star in Taurus – hides in the sun’s glare throughout the most of June. If you have binoculars and look hard enough, you might catch Aldebaran low in the east-northeast a short while before sunrise tomorrow, or on a morning later this month.
Antares can be seen in the southeast, starting at dusk or nightfall. In mid-June, Antares transits – reaches its highest point in the sky – around 11 p.m. local standard time (midnight local daylight-saving time). This applies to all time zones. Antares and Saturn move westward throughout the night, to sit low in the southwest sky before dawn.
Aldebaran is in the opposite location from Antares. The sun’s annual conjunction with Aldebaran comes on or near June 1 every year. That’s when the sun lies generally between us and this distant star in space. So, every year in early June, the sun and Aldebaran rise in the east together, cross the daytime sky together and set in the west together. That means Aldebaran is lost or obscured in the glare of the sun every year in June.
Antares shines from dusk until dawn in early June. Aldebaran is hidden in the sun’s glare from dawn until dusk in early June. Opposites!
Six months after Aldebaran’s conjunction with the sun, it’ll be Antares’ turn to be in conjunction with the sun on or near December 1. The Earth will be on the other side of the sun six months from now, so it’ll be Aldebaran that’ll shine from dusk until dawn, and Antares that’ll be lost in the glare of the sun in December.
Regulus is the only first-magnitude star to sit almost directly on the ecliptic – the sun’s yearly path in front of the stars of the Zodiac.
Antares and Aldebaran reside in close vicinity to the ecliptic and are well-known stars of the Zodiac. It’s cool that these two ruddy bright stars stand nearly opposite of one another on the great dome of sky.
Bottom line: Two similar-looking red stars, Antares in Scorpius and Aldebaran in Taurus, are on opposite sides of the sky. Thus as Antares becomes visible at nightfall and early evening, Aldebaran spends the day traveling with the sun across the sky, lost in the sun’s glare.