The sky this week from August 5 to 12
Saturday August 6
The waxing Moon is in the clutches of Scorpius in the south tonight, so let’s look north instead for darker skies.
Bright Vega in Lyra sits high in the north tonight, shining at magnitude 0. This star will one day sit above Earth’s north celestial pole, as our planet slowly wobbles on its axis and transitions from Polaris to Vega.
But Vega isn’t our main target tonight – instead we’re looking for this Astronomy columnist Phil Harrington calls “one of the first carbon stars of the summer”: T Lyrae. Sometimes called the Jewel of the Harp, this magnitude 8 luminary shows off its dark red color due to the abundance of carbon in its atmosphere, which scatters blue and green light but lets red wavelengths through to reach us. To see T Lyrae you will need larger binoculars or a small telescope. It lies just 2° southwest of Vega, amid a scattering of faint white stars. Harrington recommends aiming for Vega first, then shifting your sight so that Vega is in the northeast corner of your field of view. Then look across the starfield until you see the crimson glow of T Lyrae appear.
Sunset: 8:08 p.m.
Moonrise: 3:17 p.m.
Moon setting: 00:16
Moon phase: Waxing Gibber (64%)
Sunday August 7
Venus passes 7° south of Pollux in Gemini the Twins at 6:00 a.m. EDT. You can catch the pair before sunrise in the east; an hour before the Sun peeks above the horizon, Venus is about 20° high, with golden-hued Pollux (magnitude 1.2) in the upper left. Through a telescope, Venus’ luminous disk will appear almost full – 94% illuminated – and 11 inches wide. The planet is moving relatively rapidly east along the ecliptic and will cross neighboring Cancer within days. In less than two weeks, he will encounter the magnificent Beehive Cluster (M44).
Pollux is a star with almost twice the mass of our Sun, but is slightly cooler – although more luminous. It marks one of the twins’ heads. Directly above Pollux is Castor of magnitude 1.6, the head of the other Twin. It’s an easy to separate double with a third mate just over 1′ away. Each of the these stars is also double, which means that Castor is really a sextuple system.
Despite Pollux being the brightest star, it is designated as Beta Geminorum, while Castor was given the title of alpha.
Sunset: 8:07 p.m.
Moonrise: 4:32 p.m.
Moon setting: 00:55
Moon phase: Waxing Gibber (74%)
monday august 8
Gas giant Saturn approaches opposition, making now the best time to see its magnificent ring system and many moons. Rising at sunset, give Saturn an hour or two to move away from the horizon. Around 10 p.m. local time, Saturn is more than 15° in altitude to the southeast; its altitude will continue to rise until early morning, when it will reach its highest point above the horizon about an hour and a half past midnight.
Saturn is in Capricorn, just 2° northwest of magnitude 2.9 Deneb Algedi. The ringed planet is currently at magnitude 0.3 but will briefly brighten by 0.1 magnitude in a few days. Considered a telescope, its disk spans about 19″, while the rings – one of the most breathtaking sights in the solar system – measure almost 43″ in diameter. Enjoy it while you can, as we line up for a traverse of the ring plane, when the rings appear from Earth, in 2025.
Iapetus, which reached the greatest western elongation yesterday, still lies 9 feet west of the planet. The moon is also currently at its brightest, around 10th magnitude. On the other side of Saturn, Titan (magnitude 8.5) is 3′ east of the disc; both properties make cueing easier, especially in small spans.
Sunset: 8:06 p.m.
Moonrise: 5:44 p.m.
Moon setting: 01:43
Moon phase: Waxing Gibber (84%)
Tuesday August 9
Mars, which started the month near distant ice giant Uranus in the sky, moves into Taurus today. Rising shortly after midnight, the Red Planet is visible all morning, with the best views coming a few hours before sunrise, when it is highest in the east. Shining at a magnitude of 0.1, Mars is an object easy to see with the naked eye. To see Uranus, which is magnitude 5.8, sweep binoculars or a telescope just over 5° west of Mars toward Aries to look for its blue-gray disk.
This morning, Mars is floating 8.5° southwest of the bright Pleiades star cluster, a favorite of naked-eye and telescope observers. About 16.5° east of Mars is Aldebaran, a red giant star that marks the eye of Taurus as it is drawn across the sky. It is among – but not part of – another famous star group, the Hyades.
Mars will continue through Taurus in August, following a path that will take it between the Pleiades and the Hyades. In contrast, more distant Uranus will remain in roughly the same patch of sky all month, appearing to move much more slowly relative to the background stars.
Sunset: 8:04 p.m.
Moonrise: 6:47 p.m.
Moon setting: 02:43
Moon phase: Waxing Gibber (92%)