Tuesday, October 8
The Moon’s absence from the morning sky these next few days provides observers with an excellent opportunity to view the zodiacal light. From the Northern Hemisphere, the time around the autumnal equinox (which occurred two weeks ago) is the best for viewing the elusive glow before sunrise. It appears slightly fainter than the Milky Way, so you’ll need a clear moonless sky and an observing site located far from the city. Look for a cone-shaped glow that points nearly straight up from the eastern horizon shortly before morning twilight begins (around 5:30 a.m. local daylight time at mid-northern latitudes). The Moon remains out of the morning sky until October 12, when the waxing gibbous returns and overwhelms the much fainter zodiacal light.
Wednesday, October 9
Neptune appeared at its best at opposition one month ago, but its visibility hardly suffers this week. The outermost major planet lies some 30° above the southeastern horizon once darkness falls and climbs highest in the south around 11 p.m. local daylight time. Neptune glows at magnitude 7.8, which is bright enough to spot through binoculars if you know where to look. The trick is to find the 4th-magnitude star Phi (φ) Aquarii, which lies about 15° (two binocular fields) east-southeast of Aquarius’ distinctive Water Jar asterism. Tonight, Neptune appears 0.9° west-southwest of Phi. When viewed through a telescope, the ice giant planet shows a blue-gray disk measuring 2.3" across.
Thursday, October 10
Although the Orionid meteor shower won’t peak for another two weeks (the morning of the 22nd), you should see a few “shooting stars” associated with it before dawn these next few days. The Moon-free observing conditions in the morning sky now offer better viewing prospects than the waning Moon will at the shower’s peak. These meteors appear to radiate from the northern part of the constellation Orion the Hunter.
The Moon reaches apogee, the farthest point in its orbit around Earth, at 2:29 p.m. EDT. It then lies 252,214 miles (405,899 kilometers) from Earth’s center.
Friday, October 11
Jupiter continues to dominate the early evening sky from its perch in southern Ophiuchus the Serpent-bearer. The giant planet shines at magnitude –2.0 and stands some 15° above the southwestern horizon as twilight fades to darkness. When viewed through a telescope, Jupiter shows a 35"-diameter disk with striking details in its dynamic atmosphere. You also should see four bright points of light arrayed around the planet: the Galilean moons Io, Europa, Ganymede, and Callisto.