Aloha All...
As a "years old" LASER and LED junkie... let me just say it is a welcome relief to find this forum.
I have had, and loved, lasers from the first day they came out (yes, I remember even the old RUBY lasers). YEARS ago... my first science fair project was a HeNe laser - it was 'novel' because it had brewster windows (oh wow - hello guys, we're talking 40 years ago). Currently I'm on vacation in New Zealand - with my green laser (wish it was a 'wicked laser'
Though I've worked for numerious companies in the past (NASA, Truevsion, etc)... currently I work for Subaru Telescope (www.naoj.org) on the Big Island of Hawai'i - the largest single mirror telescope in the world. We use ADAPTIVE OPTICS which incorporates artificial laser stars to clean the image....
Let me explain...
Our most recent system (which is just now being deployed) allows us to 'clean up the astronomy image'
by either focasing on a real star (which may, or may not be where we want it to be) or on an artificial star (when the 'guide star' is NOT where we want it to be) which is generated by a laser.
At the summit of Mauna Kea, on the Big Island of Hawai'i (at 14,796 ft) there are many observatories (12, going on 13)... a number of which use lasers and adaptive optic systems, to improve the image quality (we can achieve near hubble quality with this technique).
Our system, which is the very latest - uses a sodium ion laser (beautiful orange/yellow beam - sorry, don't know the manufacturer as this particular unit is temporary until our more powerful real unit is delivered).
When a 'guide star' is not where we want it to be for observing, we project an artificial star using the sodium ion laser. The reflected beam is fed into an EXTREMLEY expensive photodiode detector system (each detector is over $1000, and there are 188 of them) and the results are viewed by 3 real-time computers.
In realtime we look at the distortion field of the beam, invert it (via some really fancy math, which I don't even understand (though we implement it) - it is not just a simple inversion) and we deform mirrors (a deformable mirror system - EXTREMELY expensive and very very very very cool - think about an 8 inch mirror which has 188 actuators which can deform the various sections of the mirror at the rate of up to 4000 hz per segment - e.g., 4000 times per second per segment - and you can't possible believe how reflective this mirror is - I'm used to laser mirrors and this mirror is as 'near perfect' as I've ever seen) to compensate for the atmospheric distortions that are revealed by the laser (or guide star in the case of a good guide star in the right spot for the desired observation).
This takes out the atmospheric distortion caused by the water vaper layers between the telescope and the target.
In the long run, this gives us one bitch'n image (very stable, very clean - the summit itself is one of the darkest places on the planet - 2500 miles from land in ALL DIRECTIONS - so the laser makes it even more so, and ALL streetlights on the Big Island have special filters on them which we can 'filter out' of the final images - so that the ambient light of the island itself doesn't affect our images).
Anyway... as I mentioned, many of the observatories (Keck, Caltech, etc) use adaptive optics similar (but not as advanced as the current one we are deploying) as ours.
One of the interesting facts is that the beams from the various observatories must be coordinated. Not only against air traffic, but against each observatory (or the beam might interfere with other observations). There is an unbelivably complex system in place to make sure that beams to not cross beams (yes, this sounds like ghostbusters, DON'T CROSS THE BEAMS - but it is in fact true) and to check for air traffic. The system involves computer coordination (which includes a human element which requires us to 'request permission to beam') as well as live human 'spotters' which use IR goggles (as each observatory uses different lasers) to spot for the lasers and also for aircraft which may stray into the area. We're talking about 14,976 feet, in Hawai'i, which believe it or not, we have MUCH SNOW (poor spotters... brrrrrrrr).
Anyway, just to share... and to say GREAT FORUM - thanks!
Aloha!
As a "years old" LASER and LED junkie... let me just say it is a welcome relief to find this forum.
I have had, and loved, lasers from the first day they came out (yes, I remember even the old RUBY lasers). YEARS ago... my first science fair project was a HeNe laser - it was 'novel' because it had brewster windows (oh wow - hello guys, we're talking 40 years ago). Currently I'm on vacation in New Zealand - with my green laser (wish it was a 'wicked laser'
Though I've worked for numerious companies in the past (NASA, Truevsion, etc)... currently I work for Subaru Telescope (www.naoj.org) on the Big Island of Hawai'i - the largest single mirror telescope in the world. We use ADAPTIVE OPTICS which incorporates artificial laser stars to clean the image....
Let me explain...
Our most recent system (which is just now being deployed) allows us to 'clean up the astronomy image'
by either focasing on a real star (which may, or may not be where we want it to be) or on an artificial star (when the 'guide star' is NOT where we want it to be) which is generated by a laser.
At the summit of Mauna Kea, on the Big Island of Hawai'i (at 14,796 ft) there are many observatories (12, going on 13)... a number of which use lasers and adaptive optic systems, to improve the image quality (we can achieve near hubble quality with this technique).
Our system, which is the very latest - uses a sodium ion laser (beautiful orange/yellow beam - sorry, don't know the manufacturer as this particular unit is temporary until our more powerful real unit is delivered).
When a 'guide star' is not where we want it to be for observing, we project an artificial star using the sodium ion laser. The reflected beam is fed into an EXTREMLEY expensive photodiode detector system (each detector is over $1000, and there are 188 of them) and the results are viewed by 3 real-time computers.
In realtime we look at the distortion field of the beam, invert it (via some really fancy math, which I don't even understand (though we implement it) - it is not just a simple inversion) and we deform mirrors (a deformable mirror system - EXTREMELY expensive and very very very very cool - think about an 8 inch mirror which has 188 actuators which can deform the various sections of the mirror at the rate of up to 4000 hz per segment - e.g., 4000 times per second per segment - and you can't possible believe how reflective this mirror is - I'm used to laser mirrors and this mirror is as 'near perfect' as I've ever seen) to compensate for the atmospheric distortions that are revealed by the laser (or guide star in the case of a good guide star in the right spot for the desired observation).
This takes out the atmospheric distortion caused by the water vaper layers between the telescope and the target.
In the long run, this gives us one bitch'n image (very stable, very clean - the summit itself is one of the darkest places on the planet - 2500 miles from land in ALL DIRECTIONS - so the laser makes it even more so, and ALL streetlights on the Big Island have special filters on them which we can 'filter out' of the final images - so that the ambient light of the island itself doesn't affect our images).
Anyway... as I mentioned, many of the observatories (Keck, Caltech, etc) use adaptive optics similar (but not as advanced as the current one we are deploying) as ours.
One of the interesting facts is that the beams from the various observatories must be coordinated. Not only against air traffic, but against each observatory (or the beam might interfere with other observations). There is an unbelivably complex system in place to make sure that beams to not cross beams (yes, this sounds like ghostbusters, DON'T CROSS THE BEAMS - but it is in fact true) and to check for air traffic. The system involves computer coordination (which includes a human element which requires us to 'request permission to beam') as well as live human 'spotters' which use IR goggles (as each observatory uses different lasers) to spot for the lasers and also for aircraft which may stray into the area. We're talking about 14,976 feet, in Hawai'i, which believe it or not, we have MUCH SNOW (poor spotters... brrrrrrrr).
Anyway, just to share... and to say GREAT FORUM - thanks!
Aloha!
