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sarongsong
2005-Jul-13, 06:55 PM
Well done 10-minute nuts-and-bolts video (http://www.ucsd.tv/library-more.asp?showID=8216) of Mauna Kea's Keck Observatory LGS (http://www2.keck.hawaii.edu/optics/lgsao/). (Yes, they turn it off for overhead aircraft and satellites.)

Hale_Bopp
2005-Jul-13, 08:41 PM
Well done 10-minute nuts-and-bolts video (http://www.ucsd.tv/library-more.asp?showID=8216) of Mauna Kea's Keck Observatory LGS (http://www2.keck.hawaii.edu/optics/lgsao/). (Yes, they turn it off for overhead aircraft and satellites.)

Great...but how do they know when there are overhead satellites and planes? That's a lot to keep track of!

Rob

sarongsong
2005-Jul-14, 02:54 AM
The FAA is notified in Honolulu and Los Angeles who issue NOTAM (hhttp://www.faa.gov/NTAP/) (notices to airmen], US Space Command approval is received, special software monitors the local airspace and onsite human observers look for errant air traffic:
"...A Laser Traffic Control System (LTCS) as been implemented... (http://64.233.179.104/search?q=cache:f0lRrBvYv58J:www2.keck.hawaii.edu/optics/aowg/docs/lgs_restrictions_v2.doc+keck+ltcs&hl=en)"

ngc3314
2005-Jul-14, 03:01 AM
The FAA is notified in Honolulu and Los Angeles who issue NOTAM (hhttp://www.faa.gov/NTAP/) (notices to airmen], US Space Command approval is received, special software monitors the local airspace and onsite human observers look for errant air traffic:
"...A Laser Traffic Control System (LTCS) as been implemented... (http://64.233.179.104/search?q=cache:f0lRrBvYv58J:www2.keck.hawaii.edu/optics/aowg/docs/lgs_restrictions_v2.doc+keck+ltcs&hl=en)"

It presumably helps that there is not a whole lot of air traffic at high elevations as seen from Mauna Kea - the airline paths from the mainland are either pretty low as they pass the Big Island or well to the north closer to Maui (where they would be the USAF's laser-avoidance problem). Interisland flights are below the summit by the time they approach the island.

That said, the other observatories on Mauna Kea may be relieved that Keck has done the trailblazing for an FAA-approved system for that site.

sarongsong
2005-Jul-14, 03:43 PM
The Lick Observatory (http://mthamilton.ucolick.org/techdocs/instruments/AO/index.html) at Mt. Hamilton in northern California also has LGS capability:
"...Laser operations are restricted by FAA rules to elevation > 45 degrees and times from midnight until 4 AM..."