Wednesday, May 17
The Moon is making its way across the sky at a good clip. Our satellite passes 0.8° north of Jupiter at 9 A.M. EDT — but before that, it occults (or passes in front of) the gas giant in an event visible from much of North America, Canada, and Greenland.
Jupiter and the Moon rise together this morning around 4:30 A.M. local time, even as the sky is growing brighter with the impending sunrise. The occultation itself takes place in daylight, with the lunar limb beginning to cover the gas giant around 7:11 A.M. EDT in Miami, 7:21 A.M. EDT in Atlanta, 6:36 A.M. CDT in Chicago, and 6:32 A.M. CDT in Denver. The timing is heavily location dependent, as with all such events, so check out the International Occultation Timing Association’s page on the occultation for more details about its visibility and timing from your location.
Because the occultation occurs in daylight, extra care must be taken if you want to watch it with binoculars or a telescope. Focus only on the area of sky where the Moon and Jupiter lie; if possible, set up your tracking scope before sunrise to avoid accidentally swinging it near the Sun while trying to locate them in the daytime sky. Fortunately, the Moon is easy to find and should keep your gaze far from the Sun. Remember to never point binoculars or a telescope anywhere near the Sun during the day unless you are using a safe solar filter.
Continuing on its journey, the Moon passes 4° north of Mercury at 10 P.M. EDT, though neither is visible at that time.
Sunrise: 5:43 A.M.
Sunset: 8:10 P.M.
Moonrise: 4:32 A.M.
Moonset: 6:20 P.M.
Moon Phase: Waning crescent (4%)
Thursday, May 18
Mars has now moved into Cancer, getting ready for a meetup with the Beehive Cluster (M44) later this month. You can preview the event by looking about 8.5° east of the Red Planet after sunset. Once the stars begin to pop out against the background sky, the glittering Beehive will start to appear. This 4th-magnitude open cluster will be visible to the naked eye once darkness fully falls; its stars spread over an area nearly 100' wide, or three times the width of the Full Moon.
If you want to look at the Beehive with a bit of magnification, that’s fine — but opt for low magnification to avoid losing too many of its scattered stars from your smaller field of view. Known since prehistoric times, the Beehive is roughly 730 million years old and sits between 500 and 600 light-years from Earth.
M44 isn’t the only Messier object in Cancer — M67, a 6th-magnitude open cluster, also lies within the Crab. To find it, scan about 8° south-southeast of M44. This grouping spans about the size of one Full Moon (30') and is a much older cluster, estimated around 3 billion to 4 billion years of age.
Sunrise: 5:43 A.M.
Sunset: 8:11 P.M.
Moonrise: 4:59 A.M.
Moonset: 7:30 P.M.
Moon Phase: Waning crescent (1%)
Friday, May 19
New Moon occurs at 11:53 A.M. EDT, leaving a perfectly dark sky overhead. Let’s take advantage and try something a little more challenging: the Blinking Planetary Nebula in Cygnus. This fascinating object is formed from the shell of gas cast off by a dying star. You’ll find it about 1.5° northeast of magnitude 4.5 Theta (θ) Cygni. Opt for a 6-inch scope or larger and wait until after full dark for the best view.
The Blinking Planetary, also cataloged as NGC 6826, is famous for doing exactly what its name implies: It appears to “blink” in and out of existence when observers switch between looking at it directly or out of the corner of their eye (i.e., using averted vision). Why is this? It’s because of the way the human eye is structured, with cells requiring more light to activate toward the center of your vision and those needing less light at the edges. So, when you look directly at NGC 6826, you see only the brighter central star, but not the faint nebular surrounding it. Switch to averted vision, though, and glance toward the edge of your eyepiece’s field of view, and the faint nebular will blink into existence as those cells pick up its dimmer glow!
Sunrise: 5:42 A.M.
Sunset: 8:12 P.M.
Moonrise: 5:29 A.M.
Moonset: 8:39 P.M.
Moon Phase: New