Planets Both Bright and Dim
Anyone can spot Venus, but what about Neptune 3 billion miles away?
The waning crescent moon graces our pre-dawn skies, appearing lower and lower in the east throughout the week. The morning of the 31st, look for it near bright Jupiter. The following morning you’ll find the moon midway between a triangle of bright stars: the Gemini twins Castor and Pollux and Procyon in Canis Minor. Monday before dawn, the moon lights the way to ruddy Mars, above and to the left in the gathering morning twilight.
Jupiter and Mars linger in the east during the wee hours before dawn. Jupiter rises around 3am with Mars appearing less than an hour later. There should be no mistaking one for the other, as Jupiter is many times brighter. Watch over the coming weeks as the gap between them — now about 15 degrees — widens, with Jupiter climbing higher and Mars sinking toward the horizon.
Saturn appears in the southwest with sunset. A dozen degrees to its lower right is the star Spica, at first magnitude roughly the same brightness as the ringed planet. Not so, however, with Venus, farther below Spica and forming a jagged line. At magnitude –4.0, Venus is almost 100 times brighter than either Saturn or Spica. Wednesday, Venus is less than two degrees from Spica.
This week offers your best hope of spying the most distant planet, although you’ll need binoculars at the least. Neptune reached opposition August 27, its closest point to Earth and its farthest from the sun, with us between the two. Neptune is fully illuminated by sunlight that traveled 2.9 billion miles to reach the distant planet and then nearly as far again to reach our eyes. Consequently, even a strong telescope shows at best a small, bluish dot. Neptune is at its highest between midnight and 1am, 27 degrees above due south, with the dim stars of Aquarius above it and the bright star Fomalhaut 15 degrees below.