Friday, 7 August 2009

Gemini laser show

Gemini put on one of their laser shows tonight, just the thing to get me out in the cold night air at 4am to freshen up a little. It's been a strange night, some excellent data and then some real rubbish when the atmosphere suddenly became very turbulent, but then improved. It allowed me to send some long sequences to our observing queue and take a short break outside with the camera.

Update 8th Aug 2009: I replaced the image with a new one, think I over-processed the original at 4am in the morning at 14K feet! The laser is a little more obvious now.


Keera Ann Fox said...

I take it you plan these things when there are no airplanes in line of the laser? We just had an incident in Norway, where people on the ground aimed lasers at landing planes, temporarily blinding the pilots (yes, the police will arrest them).

Tom said...

Keera - pointing hand held lasers at aircraft has become a real problem worldwide and people, thankfully, are starting to get some strict punishments for doing so when caught although I suspect most people are unaware of the dangers - one day it'll lead to a crash, I'm sure.

The lasers that are fired off here by Keck and Gemini are much more powerful than anything you or I could lay our hands on and would do real damage to a pilot's eye, probably permanently blind them if not worse. Fortunately, the lasers aren't fired off haphazardly!

Although I'm not involved in any laser work, I believe that they are only used after coordinating with the Federal Aviation Administration (FAA) and Air Traffic Control (ATC). As a further backup, the observatories are required to employ aircraft spotters who sit outside and watch for approaching aircraft. I suspect pilots are also given notice that lasers are being used so are aware that they should not approach the area without permission from ATC. It would be interesting to hear from someone who really knows, but there is certainly a lot of caution.

A few months ago I was outside taking some pictures while Gemini were using their laser when the laser was suddenly switched off. About 5 or 10 minutes later an aircraft flew over the summit (I suspect it was military but am not certain). After it had passed and then after a further 5 minutes or so, the laser was switched back on, so there clearly is coordination between the observatory and aircraft and/or ATC.


Keera Ann Fox said...

I would expect there to be coordination, yes. It just occurred to me to bring it up since we've had such an incident just this week here in Norway.

In spite of all the information available to us, people still manage to remain ignorant in the Age of Information.

Andrew Cooper said...


I understand your question. Our lasers are quite a bit more powerful than the handhelds that show up in the news. We can put 20 Watts into a 20cm beam, but normally only do about 14W.

We coordinate with the FAA and abide by an agreed upon set of rules for shuttering the laser around air traffic. These rules require the use of laser spotters, actual people watching for aircraft near the beam. Not a fun job, out in the cold at 14,000ft all night long. We hope to get approval to use an all sky camera with image analysis software to track aircraft over the summit.

There are notes on the aeronautical charts used by pilots with warnings about laser use over Mauna Kea. We are also linked by computer to US Space Command to shutter the laser when a satellite passes close to the beam.

There are even rules about where and when lasers can be used to prevent interference with other observatories observations.

A crash or even damage due to the observatory laser use is an unlikely scenario, we operate with full safeguards in place.

Andrew Cooper
Keck Observatory

Keera Ann Fox said...

Thank you, Andrew, for such an informative answer. It's always interesting to learn how something (or someone) works. It never occurred to me that satellites would be at risk, too. That is one heckuva laser!