Laser Pointers

[Moonhawk]

I have often seen laser pointers being used on TV to point out constellations etc.

Given recent news stories about lasers being used to blind pilots - do you think it is a good idea to use a laser pointer at night during observation/demonstration. Do you regularly use a laser pointer (e.g. attached to your telescope for pointing) and have you ever got into any bother for using it.

[ashenlight]

Hi Moonhawk

My feeling is that they aren't the best thing, particularly if you are 25 miles from an airport like me! With responsible use I imagine they could be really useful, especially when you're pointing things out to a few people at a time...

If you use the search facility at the top of this page, enter in 'laser pointer,' alot of search results should come up and you can have a read through them, see what you think

[Moonhawk]

Yeh - you are probably right. I'm not a million miles away from a couple of airports myself (Manchester and Liverpool), so its probably best not to take the chance.

[ashenlight]

Good call I use the star hop method to point stuff out to people. Get them familiar with some bright beacons - Aldebaran, Betelgeuse, Sirius, Capella, Vega, Altair, Deneb - whatever is visible when you are observing - and use the old 'go 10 o'clock from Vega, over 2 stars, down 5 o'clock to the faint one, can you see it?' trick and they'll be looking where you want them to in no time

[calibos]

I wouldn't use a Laser pointer within a couple of miles of an airport. Not because I would shine it anywhere near an aircraft myself, but because some Chav might be and I might get the blame. But I am talking within a mile or two of the runway with Planes very low on approach. I would have no problem using one 25 miles out Heck I live a long way from Dublin airport down the east coast in Wicklow county but thats still only about 15 miles.

TBH I don't think one could find many places in the UK that weren't within a 25 mile radius of some comercial airport, airfield or RAF base.

The only limitations I put on my laser use is:

Turn it off if I see a plane or helicopter in that quadrant of sky.

Don't use it right beside an airport.

[ashenlight]

It's a personal choice, my own feeling is that they are unnecessary. There are alot of planes flying over in my area and I'd spend most of the time turning it off so I wouldn't create a nuisance of myself. I don't really see the need for one once you get the hang of the star-hop technique... YMMV.

I'm glad to see you use them responsibly, calibos

[brianb]

do you think it is a good idea to use a laser pointer at night during observation/demonstration.

Only inside a building. Never outside.

Whatever the risk ...

How can astronomers call for a reduction in lights being shone into the sky if we're doing it ourselves?

[calibos]

Because it can't be seen visually by anyone who is off axis to the beam by a radius of about 10 feet or more.

Because it doesn't add to skyglow like light polution does.

Because a pilot can't see it at all above 10,000 feet no matter what and can only see it below that height if somehow we managed to shine it into the cockpit window. If that was possible, aircraft would have a lot more to worry about than surface to air missiles. A sniper rifle could take down a plane if that were the case. A state of the art missile tracking system couldn't place a laser beam in a cockpit window at that distance never mind me holding a laser handheld. Lasers are a distraction danger to Helicopters which are obviously lower and to aircraft on runway approach but other than that.....

[brianb]

Because it doesn't add to skyglow like light polution does.

Tosh. Light pollution is ANYTHING shone into the sky .... the fact that an individual laser pointer may not contribute very much is besides the point, you can make excatly the same argument for a badly shielded streetlight.

BTW the fact that we often see on forums like this high resolution images of the ISS shows that it is quite possible to aim a telescope (or a laser beam) accurately enough to hit a cockpit window from tens of miles range. And the Americans lost quite a few F-111s to rifle fire in Vietnam....

[kniclander]

How can astronomers call for a reduction in lights being shone into the sky if we're doing it ourselves?

hear hear

[themos]

How can astronomers call for a reduction in lights being shone into the sky if we're doing it ourselves?

If you take that attitude to the extreme, you'd forbid the use of Adaptive Optics lasers.