Saturday, May 15
Saturn’s largest, brightest moon, Titan, will pass due north of the planet this afternoon. Granted, that’s when it’s invisible in the bright daytime sky — instead, you can catch the magnitude 8.4 moon 1' north-northwest of Saturn early this morning.
The ringed planet, which glows at magnitude 0.5, rises in Capricornus around 1:30 A.M. local time and climbs higher in the sky until it’s lost to morning twilight. It’s located a mere 40' west of magnitude 4 Theta (θ) Capricorni. Saturn is currently about 9.7 astronomical units from Earth (1 astronomical unit, or AU, is the average Earth-Sun distance) and appears 17" in diameter. Its rings stretch 40" wide and appear 11" across the minor axis — narrower than in previous apparitions, but it means the planet’s southern polar region is becoming visible as its orientation relative to Earth changes.
Come back tomorrow morning to look again, when Titan will appear northeast of the planet.
Sunrise: 5:45 A.M.
Sunset: 8:09 P.M.
Moonrise: 8:18 A.M.
Moonset: 11:58 P.M.
Moon Phase: Waxing crescent (13%)
Sunday, May 16
The Moon passes 1.5° north of Mars at 1 A.M. EDT. At that time, however, the pair is below the horizon for Northern Hemisphere observers. By sunset, the waxing Moon has pulled away from the Red Planet, but both are still visible in the constellation Gemini as darkness falls. An hour after sunset, the Moon is nearly 10° east of the planet and is actually blocking, or occulting, magnitude 3.6 Kappa (κ) Geminorum. An hour later, the star is once again visible as the Moon continues its motion across the sky.
Mars currently glows at magnitude 1.7 and spans a mere 4" on the sky. It’s located near where the Twins’ waists are drawn, below and between the two bright stars that mark the boys’ heads: Castor (right) and Pollux (left).
Sunrise: 5:44 A.M.
Sunset: 8:10 P.M.
Moonrise: 9:11 A.M.
Moonset: —
Moon Phase: Waxing crescent (21%)
Monday, May 17
Mercury reaches greatest eastern elongation at 2 A.M. EDT, when it will stand 22° from the Sun. That makes tonight Mercury’s best evening apparition of the year.
Thirty minutes after sunset, Venus and Mercury are still aloft. Venus, which is a bright magnitude –3.9, is nearly 6° high and sits 8.5° below fainter (magnitude 0.4) Mercury. Watch for them in the darkening sky, particularly as several other bright stars begin to appear around them: Betelgeuse in Orion, Capella in Auriga, and Algol in Perseus.
Shortly before sunset, Venus passed 6° north of Aldebaran in Taurus at 7 P.M. EDT. Unfortunately, the star will set while the sky is still too bright for most observers to see.
Sunrise: 5:43 A.M.
Sunset: 8:11 P.M.
Moonrise: 10:09 A.M.
Moonset: 12:45 A.M.
Moon Phase: Waxing crescent (29%)
Tuesday, May 18
The solar system’s most distant planet, Neptune, rises a few hours before dawn in the constellation Aquarius. The magnitude 7.8 planet is within reach of binoculars, glowing about 7.5° south of the Circlet in Pisces and 5.4° east of 4th-magnitude Phi (ϕ) Aquarii. Spanning just 2" due to its great distance of 30 AU, the ice giant will appear as a flat, bluish “star.” To its west are much brighter Jupiter — also in Aquarius and easily visible with the naked eye — and Saturn, again a naked-eye object in Capricornus.
Since you’ve already got your binoculars out, let’s look farther above Neptune in the western portion of Pegasus. There you’ll find M15 — one of the galaxy’s oldest globular clusters. With a visual magnitude of 6.2 and a girth of about 18', this densely concentrated cluster is a rewarding object for any observer.
Sunrise: 5:42 A.M.
Sunset: 8:11 P.M.
Moonrise: 11:13 A.M.
Moonset: 1:27 A.M.
Moon Phase: Waxing crescent (39%)