Monday, May 16
• Another comet in the growing throng of such objects discovered by the Pan-STARRS telescope in Hawaii makes its appearance in May’s morning sky. Comet PANSTARRS (C/2013 X1) currently glows around 7th magnitude in northeastern Aquarius. (This morning, it lies less than 1° due north of 5th-magnitude Chi [c] Aquarii.) From most of the United States, you’ll need a clear, flat eastern horizon to spot the comet through a telescope just before dawn breaks.
Tuesday, May 17
• Grab your binoculars tonight and target the bright star Regulus in Jupiter’s current home constellation, Leo the Lion. Many people know that this object represents the Lion’s heart, but few realize it also is a binocular double. Regulus B, which glows at 8th-magnitude, shows up as a pinpoint nearly 3' from the 1st-magnitude primary. See “10 tempting spring binocular targets” in the May issue of Astronomy for other treats visible with just the slightest optical aid.
Wednesday, May 18
• Neptune rises shortly before 3 a.m. local daylight time this week and appears low in the southeast before dawn. The distant world glows at magnitude 7.9, so you’ll need binoculars or a telescope to spot it. Fortunately, it lies near a brighter star that will help guide you. Look for the planet 0.4° south-southeast of 4th-magnitude Lambda (l) Aquarii. You can confirm a sighting of Neptune through a telescope, which reveals the planet’s 2.3"-diameter disk and blue-gray color.
• The Moon reaches apogee, the farthest point in its orbit around Earth, at 6:06 p.m. EDT. It then lies 252,235 miles (405,933 kilometers) from Earth’s center.