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Laser Beams From Space
The laser altimeter aboard ICESat was powered on again Sept 26th and is
planned to remain on for 45 days. When atmospheric conditions and observer positioning are right, green light from the laser can be easily seen from the ground. Thin clouds, numerous scattered clouds, or haze should all provide good conditions to observe the laser beam. Clear is not good unless the observer is within a few hundred meters of the laser’s ground path. To observe the laser in even good conditions it is thought best to get close to the satellite’s ground track as the forward scattering from the Nadir pointing laser may not be visible more than a mile or less off track. The apparition's speed is remarkable as the laser spot is moving at orbital velocity. (For more info refer to the “Observing ICESat” thread on this newsgroup in March of this year) Gregg Hendry |
#2
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Laser Beams From Space
In article ,
Gregg Hendry wrote: The laser altimeter aboard ICESat was powered on again Sept 26th and is planned to remain on for 45 days. To observe the laser in even good conditions it is thought best to get close to the satellite’s ground track as the forward scattering from the Nadir pointing laser may not be visible more than a mile or less off track. Thanks for the heads-up on this, Greg. I ran out my local ICEsat passes on Heavens-Above, and although I'm getting two per night for the foreseeable future, they're all way east or west of me. ;-( Guess I'll keep checking and hope that some of them get higher in my sky. Patty |
#3
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Laser Beams From Space
In article ,
Gregg Hendry wrote: The laser altimeter aboard ICESat was powered on again Sept 26th and is planned to remain on for 45 days. To observe the laser in even good conditions it is thought best to get close to the satellite’s ground track as the forward scattering from the Nadir pointing laser may not be visible more than a mile or less off track. Thanks for the heads-up on this, Greg. I ran out my local ICEsat passes on Heavens-Above, and although I'm getting two per night for the foreseeable future, they're all way east or west of me. ;-( Guess I'll keep checking and hope that some of them get higher in my sky. Patty |
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Laser Beams From Space
ICESat's orbit was changed Saturday 10/4 and is now in a 91 day
repeating ground track orbit. Assuming the repeating ground tracks get evenly spaced around the earth over the 91 days they should be spaced approximately 14 miles apart at 40 degrees north. So with some patience ICESat should come close to you. I have observed the laser three times now and for good viewing suggest getting as close to the ground track as possible, hope for some thin clouds, and look directly towards zenith. When skys were clear observers have reported seeing only a brief green flash at zenith but when there is some cloudiness to scatter the beam the pass is much more interesting. A photograph of a recent pass scattering through clouds is posted at http://www.gsfc.nasa.gov/topstory/20...esatfirst.html Gregg Hendry Patty Winter wrote: Thanks for the heads-up on this, Greg. I ran out my local ICEsat passes on Heavens-Above, and although I'm getting two per night for the foreseeable future, they're all way east or west of me. ;-( Guess I'll keep checking and hope that some of them get higher in my sky. Patty |
#5
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Laser Beams From Space
ICESat's orbit was changed Saturday 10/4 and is now in a 91 day
repeating ground track orbit. Assuming the repeating ground tracks get evenly spaced around the earth over the 91 days they should be spaced approximately 14 miles apart at 40 degrees north. So with some patience ICESat should come close to you. I have observed the laser three times now and for good viewing suggest getting as close to the ground track as possible, hope for some thin clouds, and look directly towards zenith. When skys were clear observers have reported seeing only a brief green flash at zenith but when there is some cloudiness to scatter the beam the pass is much more interesting. A photograph of a recent pass scattering through clouds is posted at http://www.gsfc.nasa.gov/topstory/20...esatfirst.html Gregg Hendry Patty Winter wrote: Thanks for the heads-up on this, Greg. I ran out my local ICEsat passes on Heavens-Above, and although I'm getting two per night for the foreseeable future, they're all way east or west of me. ;-( Guess I'll keep checking and hope that some of them get higher in my sky. Patty |
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Laser Beams From Space
The laser altimeter on ICESat (27642) in now off and will likely remain off until February or March of 2004. Gregg Hendry |
#7
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Laser Beams From Space
The laser altimeter on ICESat (27642) in now off and will likely remain off until February or March of 2004. Gregg Hendry |
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