Several comments on Green Laser Pointers:
I use GLPs for small "star parties" of neighbors or just another
person. They are great for pointing out individual stars, no matter
how faint and for outlining constellations. In addition I use GLPs for
finders on my telescopes. I have standard finders but rarely need to
use them.
I think the problems of GLPs ruining the images obtained by
astrophotographers have been greatly exaggerated. I would be
interested in knowing how many of these photographers have actually had
their pictures corrupted by GLPs.
It is true that more and more sky parties, especially the larger ones,
are banning them. Some even kick you out if you turn one on during
nighttime hours. It's a shame that they couldn't set up fields a
short distance from the main observing field for use by people who want
to use GLPs.
Someone mentioned Howie Glatter as a good source for these pointers. I
will back that up - I have three from him. He also makes brackets so
you can mount the GLP on your telescope.
All or most GLPs do not have an on-off switch and you must keep a
constant pressure on the GLP button for it to work. You can get around
this by using a common wooden clothespin or a small rubber "O" ring
that will slide over the button and thus free up your hand.
I have never had any problems with airplanes or helicopters. At night
they all have lights so you can just wait until they leave the section
of the sky you are interested in.
GLPs can definitely harm a person's eye but I think most people are
overly concerned about this. Just use common sense and keep the GLPs
out of the hands of kids. There is an interesting article about the
effects of GLPs from the Mayo Clinic. The researcher doing the study
states, "This is a potential hazard to people's eyes, but rarely is it
going to be a practical hazard because the aversion reflex we have
naturally will cause a person to blink or turn away from a laser
light." The complete press release can be found at
http://www.mayoclinic.org/news2005-rst/2800.html
Although I obviously like GLPs, I have found one negative thing about
them. When you are showing people locations of stars, DSOs etc, I find
that many, especially kids, are more interested in the GLP than in
astronomy