October night skies
The first of September turned out to be a bust for stargazing with all of the clouds and rain in the evening, but then it was state-fair time. I should know that state-fair time equates to rain even if it is no longer officially monsoon season. Then, I will never turn down rain in New Mexico, especially this year.
October is a great month to look for the winter zodiacal light before dawn. zodiacal light, or “false dawn,” is a dim glow starting on the eastern horizon and reaching upward in a triangular shape well before actual dawn begins. You will need to start looking east about two hours before sunrise to see the zodiacal light.
What you are seeing is sunlight reflected from a disk of tiny dust particles in the plane of the solar system slowly spiraling toward the Sun. Astronomers believe asteroids bumping together in the asteroid belt, along with comet tails, replenish the dust continually. It does not take much to make enough dust in this diffuse cloud; it is estimated that there is five miles between individual particles.
Since the dust forms a complete ring around the Sun, it may be possible, under very dark skies, to see the gegenshein point, the faint spot of light in the sky diametrically opposite the Sun (midnight is the best time to look straight up). A few are said to have actually seen the zodiacal light extend all the way up to the gegenshein point.
Another October event is the annual Orionids meteor shower. Last year's event could rightly be called a storm. Don’t expect to see as many shooting stars this year. The full moon on October 21, the predicted peak of the shower, will drown out all but the brightest meteors. If you are persistent, you may be able to see about a hundred shooting stars per hour, even with the full moon.
The Orionids are caused when the Earth plows through the trail of dust left over from one of Halley's Comet’s trips to the Sun.
Venus is quickly sliding into the setting sun. After being the summer's highlight in the evening sky, its exit below the horizon will leave us with no bright planets.
Saturn rises just before midnight between Taurus and Gemini in Orion. If you have a small telescope, you can see Saturn's rings opened wide. On a still, clear night, look for the Cassini division, the gap in the middle of the rings. In 1995, we looked at the rings edge-on. This month, the rings are at their widest since that time.
The early morning is the best time to find Jupiter most of the month. Look for it in the constellation Cancer.
For much of the summer, Mars was visible in the evening sky, but has been absent of late looping behind the Sun. It has now rounded the Sun and, this month, Mars will shine in the dawn sky in the constellation Virgo.
Mercury also makes an appearance in the morning sky. It will be easiest to spot on October 8, when it will be at its brightest in the dawn light. Mercury will be near Mars, low in the sky just three degrees to the east of the red planet on October 11, before sunrise.
With the evening sky devoid of bright planets, break out your binoculars and go hunting for Uranus. While some are able to see Uranus unaided under perfect viewing conditions, the average sky watcher will probably need binoculars or a small telescope to spot this distant member of our solar system. It resides at the eastern end of Capricorn on the ecliptic. On October 15, you'll find this elusive planet five degrees north of the Moon, if you can see through the glare.
New Moon—October 6
First Quarter—October 13
Full Moon—October 21
Last Quarter—October 29