I've been wanting to post about the Z-Bolt Sapphire Presenter
which I purchased last winter, but then life intervened and now I can't do a cold-weather comparison shot! Until next winter, then, here are some salient observations:
1. Z-Bolt's blue lasers use some sort of "real" blue diode, not a pumped design like most GLPs. As far as I know, this sort of blue laser is not
easily available on eBay, yet.
2. The Sapphire Presenter does not drop in brightness even when Boston weather fell into the mid-teens. That is, between the moment when I first tried the laser after I left the warmth of my house, and when I turned it on again after it had been sitting outside in the frigid cold unused for over an hour, the beam had the same intensity to my eyes. The GLP had long since called it quits: I could see that it was on by waving my hand in front of the beam, but the intensity was so weak I couldn't see anything in the air itself (my GLP is a Wicked Lasers Core, which is supposed to be regulated).
3. The blue laser's beam is utterly visible in the night sky, even in my Boston white zone and without any dark adaptation. It is definitely useable as a night sky pointer. Curiously, the beam's color is not so much blue as nearly white. It's perhaps about half to a third the brightness of a green laser beam, but together with the more neutral coloring this is actually helpful in that it looks less piercing to passer-bys. I've had people yell up at me (I observe from my third-floor deck) because they think I'm doing something nefarious with my GLP. There has been not a peep from uninformed pedestrians after I switched to the blue laser.
4. This first generation of blue diodes have a fat-tish beam pattern, like a (non-degenerate) ellipse with the width 2-3x wider than the height. I actually thought it looked like a 3mm-wide bar at first, until I looked more closely. This means that the beam is a bit diffuse as it travels into the night sky. You wouldn't mistake it for a "laser beam"-thin GLP. This is part of the reason why the blue laser looks dimmer than the green laser; the other is the fact that our eyes are more sensitive to green.
Hope that helps people with their winter laser pointer woes. Now back to waiting for this humid soup to pass ....