NOVEMBER  2010

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742    NOVEMBER 7, 2010:   Leonids Arrive Next Week

There are four standard articles about meteors that I write each year if the moon cooperates. They deal with August’s Perseids, October’s Orionids, November’s Leonids, and December’s Geminids. A decade ago the Leonids were making headlines around the world because the object that was responsible for their activity, Comet Tempel-Tuttle, had just passed Earth. In 2000 with nearly a full moon in the east, I watched from my backyard. Over a 40 minute period, I saw 25 brilliant Leonid meteors streak across my suburban sky. The following year, the total number of Leonids seen along the East Coast climbed into the thousands, but unexpected clouds marred some of the action from where my friends and I were observing. All that extraordinary activity has passed, and Leonid numbers have settled down to their normal hourly rates of about 10-15 meteors radiating from the sickle of Leo the Lion during the hours before dawn. The best morning for viewing the Leonids will be Wednesday, November 17. Because of bright moonlight, there is no need to be up all night. The cold of November can also numb the senses very quickly. Start observing by 3 a.m., after moonset, and face east. View overhead because that is normally the darkest part of the sky from cities and suburban locales. The head or sickle of Leo will be approaching mid-sky in the east. Shooting stars that are part of the Leonid shower will appear to radiate away from this region of the sky. Layer your clothing keeping head, hands, and feet toasty. Several charcoal-based hand warmers like hunters use, one for each glove, can really make a difference. A plastic tarp over your sleeping gear will keep frost away, while an air mattress will help your back stay warmer and more comfortable. A hot caffeinated beverage will also help ward off sleepiness. An online map is available at the URL below.

Leonid meteors will be radiating from the area marked with an "X." Don't go out before moonset around 3 a.m. and don't expect a storm like a decade ago. Rates should max around dawn with 15-20 meteors visible each hour. Map by Gary A. Becker using Software Bisque's The Sky,...

743    NOVEMBER 14, 2010:   Looking Forward to December

Now I feel as if I am in the midst of the astronomical doldrums, but in December there is going to be screaming and shouting about several wonderful sky events, both influenced directly by the moon. The first is the Geminid Meteor Shower, occurring on the evening and morning of the 13th/14th, when the moon is at first quarter and sets just as the action begins. Rates of 50-100 meteors per hour can be expected. The other happens early on the morning of December 21 when the full moon is eclipsed by Earth’s shadow. If you have seen several lunar eclipses, you know that Earth’s shadow projected onto the moon is always round. The Greeks realized this from observing many lunar eclipses occurring in different seasons and visible in different parts of the sky at different times of the night. Their conclusion was that the Earth had to be spherical in shape. If the Earth would have been disk-shaped, its shadow would have appeared elliptical during most eclipses and as a dark line when projected onto the moon in an edgewise fashion. Since the moon always presented its same face towards the Earth, one might hypothesize that it could have really been a disk. However, the moon goes through a cycle of phases, and except for first and last quarter, where the sunrise-sunset line called the terminator, appears straight, this boundary is always seen as a curve. Only a sphere could produce a curved terminator. A disk would have appeared in illumination either on or off, although the brightness of the sunlit portion of the disk would have changed dramatically, depending upon the angle of illumination. Returning to eclipses, don’t think that the lunar phases result from the moon going in and out of the Earth’s shadow. They are just a natural consequence, as mentioned before, of a spherical body, the moon, in orbit around the Earth.

744    NOVEMBER 21, 2010:   Astrophotography and the New Canon 60D

If you are a regular reader of this column, you know that I am interested in astrophotography. Years ago, I chose Canon’s digital imaging system over Nikon cameras and lenses which I had used extensively during the several decades that I was using film. I went from Canon’s 20D and 20Da to a 40D, and within the last month I bought a 60D. I did not purchase the 30D or 50D Canon models. I also acquired an adapter which allows me to use Nikkor/Nikon lenses with my Canon bodies, a very sweet setup which has saved me tons of money. Because I take my telescope with me when I travel, my choice of equipment has always remained small and very portable. Hearing that the 60D was lighter than its predecessors was good start, but what immediately attracted me to this camera was its high resolution and movable flip out screen. Focusing is always a hassle. When using the other D’s, I was always on my back in a half sit up position, making fatigue a real problem after an hour of taking pictures. Now I’m sitting or kneeling on the ground, but I could be upright in a chair if I chose to be. With the high resolution screen (not a big change from the 50D), critical focusing is easier to obtain, but make no mistake, it still takes plenty of patience and practice due to natural atmospheric turbulence and human made telescope vibrations that are created during the focusing process. My 10x live view gives me a magnification of about 425 times, a great way to observe the moon, even if I am not taking pictures. The 18 megapixel sensor has more than double the resolution of the 40D and is 1.5 times greater than the 50D. With a tight focus, detail is more easily resolved, and the images seem to be more forgiving when manipulated. You can see some lunar images that I took last week at www.astronomy.org.

The moon at six days. Canon 60D, EFL 2136mm, F/14.4, 1/40 sec., ASA 200... Gary A. Becker image from Coopersburg, PA...

The moon at nine days showing the area of the enlarged image in the next photo.

The moon at nine days highlighting the Straight Wall, a 65 mile fault line running NW to SE along the eastern side of Mare Nubium. The 12 mile in diameter crater, Birt, just to the west of the Straight Wall can also be seen. Canon 60D, EFL 2136mm, Questar, 90mm, F/14.4, 1/40 sec., ASA 200... Gary A. Becker image from Coopersburg, PA...

745    NOVEMBER 28, 2010:   Brian Marsden: Astronomer Go-To

The astronomical world lost a key player with the death, on November 18, of Brian Marsden, 73. He was responsible for sifting through the vast amounts of astronomical information necessary to calculate the accurate orbital paths of new comets and asteroids. He coordinated the efforts of the International Astronomical Union’s Central Bureau for Astronomical Telegrams (1968-2000) and Minor Planet Center (1978-2006) in Cambridge, Massachusetts, and as such was on the forefront of virtually every new discovery made in astronomy that required additional observations to refine positional accuracy. I spoke to Marsden once, a long time ago, trying to get an informational update about a comet that I was trying to observe. I thought the conversation would last, maybe 30 seconds, but the man that I found on the other end of the line was a very affable human being, albeit a little difficult to understand with his thick British accent. We talked for over five minutes, and he went out of his way to make sure that I had the correct information that I needed. Just like Carl Sagan became the common man’s astronomer, Marsden became the point man for the media’s search for information about new discoveries. Marsden’s whole life was spent in the pursuit to refine the mathematics about how to predict where objects were in the solar system. He got a special joy from thwarting astronomical doomsayers who discovered asteroids that seemed to be headed for Earth impact and developed mathematical tools to construct more accurate orbits in shorter time spans to more rapidly dispel these rumors. The New York Times once described Marsden as the “Cheery Herald of Fear.” Eclipse chaser, Joe Rao, probably summed up Marsden best by saying he would talk to anyone regardless of his station in life, “a really nice guy!” We’ll miss you Brian.

This composite image of Jupiter and three of its four Galilean satellites was taken on November 28 at 9:02 p.m. A 7-inch Questar, F/14.4 was used to snap Jupiter at 1/30 second, ASA 200. The original picture was underexposed by several stops. North is up. Prominent in the picture is Jupiter’s Northern Equatorial Belt. The Southern Equatorial Belt has been absent since May of this year. Gary A. Becker photo from Coopersburg, PA...