Suburban Astronomy and the Gamma Ray Burst Here |
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I live just outside of Rockville, Maryland, and to the east south east of my home lies the White House just 17 miles away as the crow flies. I measured the sky in the direction of Rockville a few nights ago (due east), and found the limiting magnitude to be 1.7 at roughly 45 degrees altitude. I determined this value by observing a known field at a known magnification. I then compared the star patterns I could see with the output from my planetarium program TheSky, from Software Bisque. I shaved off 10ths of a magnitude from the screen projection until what I saw on the screen matched the field of view through the eyepiece. (To gain an appreciation of the widespread light pollution in the Washington Metropolitan Area, click here to see a map, or here to get the story behind the map. If you are intrigued or saddened by the map or by the story, click here to visit the International Dark Sky Association (IDA)., or click here to guage the sense of loss of a person who grew up in this area in the 60's, and then later returned to the Rockville/Potomac area as an adult to be saddened by the loss of a wonderful natural gift.) I then computed what the naked eye limiting magnitude was given the telescopic observed limiting magnitude. (Formulas for this can be gotten from me, just send me an e-mail). The reason for using the telescopic limiting magnitude is that 9th and 10th magnitude stars are much more common than 1st and second magnitude stars, and can provide a better estimate of visual limiting magnitude in skies like we have here in the Rockville area. With such skies, one might be tempted to ask what kind of astronomy can be done? The answer to this question is complex because, almost any kind can be done, but special techniques are required to achieve visual satisfaction. This page addresses these techniques. 1) Dark Adaptation for the eyes 2) CCD Cameras for grasp 3) Aperture for the really neat stuff 4) Digital Setting Circles for finding your way around the celestal sphere. 5) Light Buckets for defeating urban light pollution. and 6) For the northern, and not-so-northern climates, staying warm through it all, complements of Northern Virginia Astronomers.. For a fascinating look at the world of Optimum Detection Magnification (ODM) see Mel Bartel's link. To see the impact of CCD imaging, large aperture, and digital setting circles on the Suburban Astronomy scene, click here. Before this technology: It used to be when I was a kid on our farm in Missouri, I could see the Milky Way just by looking up into the night-time sky. It wasn't faint. It seemed like a bold river of white, and it was just beautiful. My kids can't see it at all here in Rockville. The other day, I ran across this picture. You might look at this picture and say, gee, I can see where I live. I can see Chicago, or Denver, or Boston, or Washington DC. Please look more closely. This is a picture of the US taken from space at night. The only way a satellite can take the image is if large amounts of light are being cast straight up! I can understand wanting to illuminate the ground for security purposes, but the criminal element rarely operate above ground level, so why are we illuminating the undersides of airplanes and bats? Have we nothing on earth more useful to do with our lighting dollar? A group headquartered in Tuscon, Arizona, called the International Dark Sky Association (IDA) thinks that we do. For myself, I would rather save the money spent on such waste on cancer research. I would also very much like my grandkids to have back that wonderful night sky that I had growing up. Those memories continue to to this day to inspire my love of astronomy. |
Suburban Astronomy Page |
I live just outside of Rockville, Maryland, and to the east south east of my home lies the White House just 17 miles away as the crow flies. I measured the sky in the direction of Rockville a few nights ago (due east), and found the limiting magnitude to be 1.7 at roughly 45 degrees altitude. I determined this value by observing a known field at a known magnification. I then compared the star patterns I could see with the output from my planetarium program TheSky, from Software Bisque. I shaved off 10ths of a magnitude from the screen projection until what I saw on the screen matched the field of view through the eyepiece. (To gain an appreciation of the widespread light pollution in the Washington Metropolitan Area, click here to see a map, or here to get the story behind the map. If you are intrigued or saddened by the map or by the story, click here to visit the International Dark Sky Association (IDA)., or click here to guage the sense of loss of a person who grew up in this area in the 60's, and then later returned to the Rockville/Potomac area as an adult to be saddened by the loss of a wonderful natural gift.) I then computed what the naked eye limiting magnitude was given the telescopic observed limiting magnitude. (Formulas for this can be gotten from me, just send me an e-mail). The reason for using the telescopic limiting magnitude is that 9th and 10th magnitude stars are much more common than 1st and second magnitude stars, and can provide a better estimate of visual limiting magnitude in skies like we have here in the Rockville area. With such skies, one might be tempted to ask what kind of astronomy can be done? The answer to this question is complex because, almost any kind can be done, but special techniques are required to achieve visual satisfaction. This page addresses these techniques. 1) Dark Adaptation for the eyes 2) CCD Cameras for grasp 3) Aperture for the really neat stuff 4) Digital Setting Circles for finding your way around the celestal sphere. 5) Light Buckets for defeating urban light pollution. and 6) For the northern, and not-so-northern climates, staying warm through it all, complements of Northern Virginia Astronomers.. For a fascinating look at the world of Optimum Detection Magnification (ODM) see Mel Bartel's link. To see the impact of CCD imaging, large aperture, and digital setting circles on the Suburban Astronomy scene, click here. Before this technology: It used to be when I was a kid on our farm in Missouri, I could see the Milky Way just by looking up into the night-time sky. It wasn't faint. It seemed like a bold river of white, and it was just beautiful. My kids can't see it at all here in Rockville. The other day, I ran across this picture. You might look at this picture and say, gee, I can see where I live. I can see Chicago, or Denver, or Boston, or Washington DC. Please look more closely. This is a picture of the US taken from space at night. The only way a satellite can take the image is if large amounts of light are being cast straight up! I can understand wanting to illuminate the ground for security purposes, but the criminal element rarely operate above ground level, so why are we illuminating the undersides of airplanes and bats? Have we nothing on earth more useful to do with our lighting dollar? A group headquartered in Tuscon, Arizona, called the International Dark Sky Association (IDA) thinks that we do. For myself, I would rather save the money spent on such waste on cancer research. I would also very much like my grandkids to have back that wonderful night sky that I had growing up. Those memories continue to to this day to inspire my love of astronomy. |
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Suburban Astronomy and the Gamma Ray Burst Here |
