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

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

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

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

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

The laser altimeter on ICESat (27642) in now off and will likely remain
off until February or March of 2004.

Gregg Hendry

The laser altimeter on ICESat (27642) in now off and will likely remain
off until February or March of 2004.

Gregg Hendry