I had not seen Natalie Angier's article in the Science Times
The Biggest of Puzzles Brought Down to Size before wrapping up April's Moondark. Spooky ... We both must have been influenced by what I consider to one of the most empowering books I have ever read, John Harte's , Consider a Spherical Cow: A Course in Environmental Problem Solving. It's still in print!
Monday, March 30, 2009
Sunday, March 29, 2009
How Many Amateur Astronomers Are There in the US?
Here are two very rough ways to get an answer:
1. There are 300,000,000 people in the US, and maybe 1 in 100 (at most) has a telescope. Thus there are 3 million amateur astronomers in the US.
2. There are 50 states in the US, and each one has, say 4 astronomy clubs, with perhaps 150 members each. That's 30,000 amateurs.
While these numbers seem reasonable, the overall result is pretty poorly constrained. Can we do better?
Another way to estimate the number is from magazine circulation. A bit of web-searching reveals that Sky & Telescope and Astronomy magazines have circulations around 100,000, so double or triple that (since not all amateurs subscribe) to yield 300,000. By the way, that's the geometric mean of the two estimates above. Does 1 in 1000 people owning a telescope seem right to you? Is that close enough?
Probably a more pertinent question at this point is just what is a amateur astronomer? Certainly arm-chair enthusiasts count, as do those joining a club or purchasing a telescope.
How would you recognize a bona fide star-gazer if you saw one? Knowledge of the sky, solar system and constellations? Size of telescope and skill at using it under the starry sky? Total dollar investment in optics electronics and other accessories? Willingness to share what they know with those less familiar with the sky?
1. There are 300,000,000 people in the US, and maybe 1 in 100 (at most) has a telescope. Thus there are 3 million amateur astronomers in the US.
2. There are 50 states in the US, and each one has, say 4 astronomy clubs, with perhaps 150 members each. That's 30,000 amateurs.
While these numbers seem reasonable, the overall result is pretty poorly constrained. Can we do better?
Another way to estimate the number is from magazine circulation. A bit of web-searching reveals that Sky & Telescope and Astronomy magazines have circulations around 100,000, so double or triple that (since not all amateurs subscribe) to yield 300,000. By the way, that's the geometric mean of the two estimates above. Does 1 in 1000 people owning a telescope seem right to you? Is that close enough?
Probably a more pertinent question at this point is just what is a amateur astronomer? Certainly arm-chair enthusiasts count, as do those joining a club or purchasing a telescope.
How would you recognize a bona fide star-gazer if you saw one? Knowledge of the sky, solar system and constellations? Size of telescope and skill at using it under the starry sky? Total dollar investment in optics electronics and other accessories? Willingness to share what they know with those less familiar with the sky?
Sunday, February 22, 2009
Wrong Way Snowball
Comet Lulin and why it's racing the wrong way across the sky at Moondark for March. Here, a fuzzy, greenish Lulin forms the bottom vertex of a triangle with η and 10 Virginis on the morning of 21 February (composite of 10, 15-s untracked exposures with a Canon 350D).
Friday, February 13, 2009
When 13 = 1234567890
Today is Friday the 13th, the first of three this year1. It’s also 12345678902, that is the number of seconds since midnight on New Years 1970 not counting leap seconds, known as Unix time, the internal reckoning of my MacBook (date -r 1234567890) and various Ubuntu boxes. Try this:
perl -e 'print "\n",scalar localtime(1234567890),"\n\n";'
Excel counts days from the beginning of the 20th century, but Windows and Mac versions use different starting points. See for yourself by comparing PC's and Macs by typing: =DATEVALUE("1-Jan-1904"). Astronomers count Julian days from 4713 BCE, but start at noon UT on the first day of the year. Here, 1234567890 = JD 2454876.27188.
Clearly there are many ways to keep time and mark a calendar. Civilizations come and go along with their calendars: someone's, somewhere is rolling over or reaching some magic number all the time. So it is difficult to get too worked up over the Mayan calendar that will roll over in 2012, on 21 December. There is no need to worry, really there isn't.
1The others are in March and November
2Exactly so at: 6:31:30 pm EST
perl -e 'print "\n",scalar localtime(1234567890),"\n\n";'
Excel counts days from the beginning of the 20th century, but Windows and Mac versions use different starting points. See for yourself by comparing PC's and Macs by typing: =DATEVALUE("1-Jan-1904"). Astronomers count Julian days from 4713 BCE, but start at noon UT on the first day of the year. Here, 1234567890 = JD 2454876.27188.
Clearly there are many ways to keep time and mark a calendar. Civilizations come and go along with their calendars: someone's, somewhere is rolling over or reaching some magic number all the time. So it is difficult to get too worked up over the Mayan calendar that will roll over in 2012, on 21 December. There is no need to worry, really there isn't.
1The others are in March and November
2Exactly so at: 6:31:30 pm EST
Thursday, February 12, 2009
Happy 200th Birthday Charles and Abe!
Not sure I can add anything insightful to what’s already out there about these two individuals. Except my opinion that it’s pointless to try to compare them, and only a little more enlightening to ask “What would they think if they came back today?”
After all, they’re still here, their names are attached to their original accomplishments as well as to ideas, causes and controversies in the forefront today, but ones that they could have known nothing about. Darwin’s head often appears on a monkey’s body, although he didn’t discuss the evolution of man in the 1859 On the Origin of Species. Darwin’s finches put the Galapagos Islands on today’s map as the premiere eco-travel destination.
We put Lincoln’s head on the penny, a coin that scarcely anyone will bother to pick up off the ground. In a far more appropriate setting, you can read some of the grandest of his writings etched in the wall of the Lincoln Monument. In the Gettysburg Address, Lincoln spoke of unfinished work.
It’s fortunate they are still around as we’re not done with them yet, and we have work to do. Natural selection drives evolution, fossils are the evidence and molecular biology explains how it works, but only about half of Americans believe in evolution. And recent political events aside, racism is still here. It manifests itself in social and economic inequality in this country and around the globe.
So it’s a good thing to recognize Charles and Abe, I think.
After all, they’re still here, their names are attached to their original accomplishments as well as to ideas, causes and controversies in the forefront today, but ones that they could have known nothing about. Darwin’s head often appears on a monkey’s body, although he didn’t discuss the evolution of man in the 1859 On the Origin of Species. Darwin’s finches put the Galapagos Islands on today’s map as the premiere eco-travel destination.
We put Lincoln’s head on the penny, a coin that scarcely anyone will bother to pick up off the ground. In a far more appropriate setting, you can read some of the grandest of his writings etched in the wall of the Lincoln Monument. In the Gettysburg Address, Lincoln spoke of unfinished work.
It’s fortunate they are still around as we’re not done with them yet, and we have work to do. Natural selection drives evolution, fossils are the evidence and molecular biology explains how it works, but only about half of Americans believe in evolution. And recent political events aside, racism is still here. It manifests itself in social and economic inequality in this country and around the globe.
So it’s a good thing to recognize Charles and Abe, I think.
Sunday, February 8, 2009
So Long Snow Moon!
The ice on the pond has melted, the songbirds are back and the sunshine is warm! Even though we're still 20 days (and 3 hours, but who's counting) from meteorological spring on 1 March and 40 days from our astronomical vernal equinox: I'm calling it: Spring is here.At right, the tonight's full moon, enroute to a penumbral eclipse in about 12 hours, shows there's no leaves on the tree—not yet.
Monday, January 26, 2009
Happy and Prosperous Lunar New Year!
Or: 新年快乐 and 恭喜发财 (mostly just to see if I could cut and paste these characters—it works!) in the year 4707, 4706, or 4646. So many calendars, so little time ...
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