Fifty years ago, on Oct. 4, 1957, the Soviet Union launched the world’s first artificial satellite.

Sputnik 1 weighed 183 pounds and looked like a shiny basketball with four antennae ranging in size from 7.9 to 9.5 feet in length. It circled the Earth every 98 minutes at heights ranging from 142 miles to 588 miles. It did little more than transmit a continuous beeping sound but it was at a frequency that could be picked up by amateur ham radios and quickly became known as “the beep heard around the world.”

It fell from orbit on Jan. 4, 1958. Sputnik 1 had an impact far beyond its minimal capabilities. Carried aloft by a Soviet intercontinental ballistic missile, there was a nationwide panic that we were being beaten by the Soviets militarily as well as in space. Senate Majority Leader Lyndon Johnson pushed a space program in Congress that led to the creation of NASA. Sen. John F. Kennedy made space his priority and, as president four years later, vowed to put a man on the moon within a decade. The space race was born the day Sputnik 1 went into orbit.

Focus on the planets

Mercury makes a brief appearance very low on the western horizon before disappearing into the glow of sunset during the first few days of the month.

Venus shines brightly high in the east at dawn. Viewers with telescopes should be able to see the planet half illuminated and half in darkness on Oct. 28.

Mars rises shortly before midnight as October opens but will be visible by 9:30 p.m. at month’s end. Look for Mars as an orange-red point of light in the east-northeast. On Oct. 3, the Red Planet lies immediately to the upper right of the moon.

Jupiter is low in the southwest at twilight and continues to sink toward the horizon so that, by month’s end, the gas giant will be setting an hour after darkness falls.

Saturn lies on the eastern horizon at dawn to the lower left of, and much dimmer than, its companion Venus. Saturn appears somewhat smaller and dimmer than usual for its ring system is slowly closing and is now less than 10 degrees from being edgewise when it essentially is invisible. That sad state of affairs will take place in 2009.

Neptune is high in the south in the constellation Capricornus as darkness falls. It may be found with a good set of binoculars and a finder chart such as that printed in the July 2007 issue of Sky & Telescope.

Uranus rises around midnight in the south in the constellation Aquarius. Much brighter than Neptune, Uranus may be easily located by a neat trick described in the October issue of Astronomy magazine. Find the Square of Pegasus high in the south and draw an imaginary line down its right side until you encounter a solitary bright star. This is Fomalhaut. Uranus is located roughly midway between Fomalhaut and the Square’s lower star.

October events

1 Sunrise, 6:33 a.m.; sunset, 6:17 p.m.

2 The very early morning hours find the moon almost directly above orange-red Mars on the east-northeast horizon. The two bright stars far to the lower left are Castor and Pollux.

3 Moon in last quarter, 6:07 a.m.

7 Check the eastern horizon during the pre-dawn hours for the most spectacular viewing opportunity of the month. Regulus, Venus, and Saturn form a tight triangle with a thin crescent moon captured within it.

9 This is the peak night for the Draconid meteor shower, a swarm of slow-moving meteors that are circumpolar during the early evening hours. The last significant shower, about 35 meteors an hour, occurred in 2005, but near ideal viewing conditions, the new moon just two days away, make this an event worth viewing.

11 New moon, 1:01 a.m.

13 The moon is at apogee, its farthest distance from Earth, today.

14 Jupiter is well up on the southwest horizon about a half-hour after sunset with the moon directly below and Antares immediately to the lunar right.

19 Moon in first quarter, 4:33 a.m.

20 Venus dominates the pre-dawn eastern horizon with Saturn directly above and Regulus slightly to the upper right.

21 This is the peak night for the Orionid meteor shower. As the name implies they originate from the constellation Orion and the pre-dawn hours should afford up to two dozen fast, faint meteors an hour if conditions are good.

23 The sun enters the astrological sign of Scorpio but astronomically is still in Virgo.

26 Full moon, 12:52 a.m. As the first full moon after the Harvest Moon, this is known as the Hunter’s Moon. The moon is at perigee, or closest approach to the Earth, and the combination of these two events may result in very high tides.

28 Last Sunday in October. Set clocks back one hour as we make the change back to Standard Time.

31 Halloween or the eve of All Saints Day, a cross-quarter day marking the midpoint between the fall equinox and winter solstice. The sun enters Libra on the ecliptic but. Sunrise, 6:12 a.m.; sunset, 4:26 p.m.