Find your way around the night sky! Below is a free sky map for OCTOBER 2015 as well as a printable version, courtesy of astronomer Jeff DeTray.
Sky Map for OCTOBER 2015
Each month, Jeff DeTray’s Sky Maps provides a sky map which highlights beautiful events in the evening sky—stars, constellations, planets, conjunctions with the Moon, meteor showers, and other amazing celestial objects. Follow more of Jeff’s sky adventures at AstronomyBoy.com.
Click-and-Print Sky Map
Just click here or on the image below to open the printable map—then bring outside!
Sky Map Highlights: October 2015
Mercury and Friends
October just might be the best month of this year for viewing planets. No fewer than four are visible in the same part of the sky at the same time, including one that most people never see, but you’ll have to wake up early to catch the show.
Mercury, named for the Roman messenger of the gods, is the innermost planet, closest to the Sun. As such, it spends most of its time lost in the Sun’s fierce glare. Only on rare occasions does Mercury venture far enough from the Sun to be seen easily from Earth, and October 2015 is one of those times.
At midmonth, you can see Mercury about an hour before sunrise, low in the East. For the best view, pick a location free from buildings and trees to the east. Mercury looks like a medium-bright star, so it’s not spectacular. But if you see it, you’ll join the ranks of a small, exclusive group of Earthlings.
A bit higher in the sky, and therefore easier to see, the planets Jupiter and Mars appear next to one another. Together, they look like a bright “double star,” with the giant planet Jupiter the brighter of the two. When two celestial objects appear in such close proximity, the phenomenon is known as a conjunction. Conjunctions of planets occur a dozen or more times a year, but this one is especially close.
The proximity is an illusion, however. In fact, Jupiter is much farther from us than is Mars. On the date and time of the Sky Map, Mars is 210 million miles from us, but Jupiter is 571 million miles distant. The two planets just happen to line up for our viewing pleasure!
Still higher in the sky, and the brightest object in view, is the planet Venus. The second planet from the Sun, Venus is the brightest of the planets and is brighter than any star (except our Sun, of course). The level of brightness is due to the planet’s atmosphere, which reflects sunlight extremely well.
Mercury, Venus, Mars, and Jupiter are the four planets closest to Earth and thus were the first to be visited by spacecraft.
Venus, being closest, was the first to be explored; NASA’s Mariner 2 flew by in 1962. In the 1970s, Soviet Venera landers touched down on Venus, and additional flyby missions were conducted by NASA. Probes determined that Venus is extremely hot and its atmosphere consists mainly of carbon dioxide—not conducive to supporting life.
Two NASA probes have been sent to Mercury. Mariner 10 flew by the planet three times, twice in 1974 and once in 1975, and Messenger orbited Mercury for four years beginning in 2011.
Mars has been explored by dozens of spacecraft from several countries. Many early attempts to reach Mars ended in failure. In 1965, NASA’s Mariner 4 craft flew by Mars and provided the first detailed photos of the surface. In 1971, NASA’s Mariner 9 orbited Mars, and a few months later, a lander from the Soviet Mars 2 crashed onto the surface.
Jupiter, the solar system’s largest planet, is much farther from Earth than the other three planets on this month’s map. Starting in 1973 with NASA’s Pioneer 10 spacecraft, there have been eight flyby missions to Jupiter. In 1995, NASA’s Galileo became the first and only mission to orbit Jupiter. No spacecraft will ever land on Jupiter because the planet has no solid surface.
OCTOBER 2015 Sky Map
Click here or on image below to enlarge (PDF)
Sky map produced using Chris Marriott’s Skymap Pro
See our Sky Watch page for more highlights of the monthly sky, courtesy of The Old Farmer’s Almanac.