I'm sure you know that many regulations have been implemented over the past few years limiting the green laser pointer you can buy. While I prefer laser pointers that are relatively high in mW (milliwatts), I no longer recommend high power laser pointers. Luckily for you, this doesn't mean that all astronomical laser pointers are now illegally purchased and not working.
If you want a laser pointer that is visible in the night sky, I recommend following these two tips. First, select the green laser pointer. This is because green is best for viewing, especially at night. Your eyes are more sensitive to a green laser pointer than to another color. The second is to try to get a 5mW laser pointer. That's the highest laser power you can get in the US right now, and it's definitely more than enough for what we're trying to do here. In fact, any 5mW green laser pointer will work if you're looking for a good option for astronomy. Here are some I've seen that get the job done.
Tips for star safety and outdoor use
First, you should choose a green laser because green is easier to see with the human eye. Red, violet, and blue are also visible, but green is easier to see and can be used at lower power, providing better visibility. A 5mW green laser is 5-10 times more visible than a 5mW red laser. Second, you should start with a 5mw-50mw laser pointer as it has enough power to point things out while still being safe to use without glasses.
While many astronomy watchers and astronomy enthusiasts use high-power lasers, such as handheld devices or laptops, this is not required. Dual power high power laser pointer are more than enough. The reason many people still use high power lasers is because of the visibility of the beam. So if you decide to use a more powerful laser than a pointer, be sure to take extra safety precautions and make sure everyone else around you is wearing safety glasses.
