Thursday, April 24, 2014
By Bernie Reim
This is usually a month of transition as the foliage slowly fades away before the snow starts flying in earnest. The terrestrial landscape will turn bleaker as the nights keep getting longer and the cold begins to settle in.
SKY GUIDE: This chart represents the sky as it appears over Maine during November. The stars are shown as they appear at 10:30 p.m. early in the month, at 8:30 p.m. at midmonth and at 7:30 p.m. at month’s end. No planets are visible at chart times. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom.
Chart prepared by George Ayers
But as soon as you look up from Earth, you will see that this will be a rich, exciting and unpredictable month for celestial treasures. Conjunctions and eclipses are predictable for thousands of years into the future, but meteor showers can be a surprise in their detailed unfolding. The real surprise this month and especially next month will be the exact nature of how the event called Comet ISON unfolds.
Discovered just over a year ago on Sept. 24, 2012 by two Russian astronomers using a 15.7-inch telescope named the International Scientific Optical Network, which was designed to detect, monitor and track near-Earth asteroids and comets, this faint fuzzy object was only 18 magnitude, or 63,000 times fainter than anything the naked eye can detect when it was first spotted. Now it can be seen glowing at about 10th magnitude just above Mars in the early morning sky in the constellation of Leo. It could become visible with the naked eye by the end of this month.
This is probably Comet ISON’s first trip in from the Oort cloud, where all the new comets originate. Located 50,000 astronomical units away, or nearly one light year, this is 1,000 times farther away than Pluto and the other Kuiper Belt objects.
There is a theory that Comet ISON is related to the Great Comet of 1680 because it is following nearly the same path. That was the first comet discovered with a telescope and then it became bright enough to see in the daytime, but nothing dramatic happened on Earth.
ISON will reach perihelion, or its closest approach to the sun, on the 28th, which happens to be Thanksgiving this year. It will pass very close to our sun, less than one solar diameter away, which is 865,000 miles. Since its nucleus is relatively small at only three miles across (Comet Hale-Bopp’s nucleus was more than 10 miles across) it may get torn apart by the sun’s enormous gravity, which is much stronger than the nucleus’s weak self-gravity. The surface of the comet will also be fried to about 5,000 degrees, hot enough to melt iron. No one knows if the comet will even survive its dramatic and dangerous close encounter with our life-giving sun but if it does, it will provide a tremendous show in early December in the morning sky. Recent comets that survived close encounters with the sun and became quite spectacular were Comet West in 1976 and Comet Lovejoy in 2011.
Before all the drama and uncertainty around this great comet starts to unfold, there will be a nice little partial solar eclipse visible all along the Eastern Seaboard. We will get one of the best views in this country, since 55 percent of the sun will be covered by the new moon right at sunrise, which will be 6:20 a.m. Don’t forget to set your clocks back one hour that Sunday or you will miss the whole event. You should predetermine a good spot for this event, preferably overlooking the ocean, and get there by 6 a.m. so you can be prepared if you plan to photograph it. Make sure you use safe solar filters for your eyes, and cameras and binoculars. A Number 14 welder’s glass is safe, as are aluminized mylar filters.
If you could travel to Africa that day, you would witness a very rare hybrid solar eclipse, which means that it will be an annular eclipse for a while with a brilliant ring of sunlight left around the moon, then a total solar eclipse for a while when the beautiful streamers in the solar corona become visible for a minute or so. Most of us won’t go to Africa but it’s not too early to prepare for the Aug. 21, 2017 total solar eclipse visible in a narrow path across this country from Oregon to Georgia. Standing in the moon’s shadow as its shadow cone gently brushes across Earth will be an experience you will never forget.
There will also be a meteor shower this month, the Leonids on the morning of the 17th. Unfortunately the moon will be full and wash out most of the 20 or so meteors per hour that you could see. The great Leonid shower in 2001 was one of the best astronomical events I have seen in my 30 years of observing. We had just built our Starfield Observatory in Kennebunk, so we had a good, open sky site. We saw nearly 3,000 meteors in three hours, about one every four seconds. I also saw about 10 bolides that lit up the whole sky and left long, twisting, dusty trails. There was not a single lull over 10 seconds long, just a constant rain of meteors. I even saw seven of them in one or two seconds, emanating from their radiant in Leo. That was the first and only time I had a true sense of Earth’s constant motion at 67,000 mph around the sun as we encountered all this comet dust.
Jupiter starts the month rising by 10 p.m. and it will rise by 7 p.m. in Gemini by the end of the month. The king of the planets will begin its retrograde motion on Nov. 7.
Venus is still an evening planet and it will get brighter and brighter even as it is getting thinner and less illuminated by the sun. It will be a 31-percent illuminated crescent by the end of November.
Most of the action takes place in the morning sky this month. Mercury, Spica and the comet will form a nice conjunction one hour before sunrise in the east-southeastern sky starting by the middle of the month. Then keep watching as Saturn joins the trio by the 22nd and gets closer to Mercury even as the comet sinks lower into the morning sky.
• Nov. 1-15. The zodiacal light will be visible in the east about 90 minutes to two hours before sunrise. Look for a tall, broad pyramid of light with Mars near its apex.
• Nov. 3. A partial solar eclipse will be visible for us this morning at sunrise. New moon is at 7:50 a.m.
• Nov. 5. The Taurid Meteor shower peaks this morning.
• Nov. 6. Venus will be near the waxing crescent moon this evening.
• Nov. 8. Edmund Halley was born on this day in 1656.
• Nov. 9. Carl Sagan was born on this day in 1934.
• Nov. 10. First-quarter moon is at 12:57 a.m.
• Nov. 14. Apollo 12 was launched on this day in 1969. It was the second successful mission to land on the moon.
• Nov. 17. Full moon is at 10:16 a.m. This is also called the Frosty or Beaver Moon. The Leonid meteor shower peaks this morning. The moon will be near the Pleiades this evening.
• Nov. 20. Edwin Hubble was born on this day in 1889. He figured out that the Andromeda Galaxy is a completely separate galaxy and not just a nebula within our own galaxy or island universe.
• Nov. 25. Last-quarter moon is at 2:28 p.m. Saturn is less than 1 degree below Mercury, which is about three times brighter than the ringed planet. Comet ISON should be visible without binoculars 5degrees below the pair of planets.
• Nov. 27. On this day in 1971, the Mars 2 probe became the first artificial object to hit Mars.
• Nov. 28. Comet ISON reaches perihelion with the sun, less than one solar diameter away.
Bernie Reim of Wells is co-director of the Astronimical Society of Northern New England.