The beam of 5mW green laser pointer is easily visible at night. If someone else is lying on the ground next to you, they might too, faintly. However, it is just only a Class IIIa laser, it is quite safe than those of high powered lasers. In totally dark sky, you will see the green laser beam about 100 feet long. In clean and dry night, the green laser light is even brighter and visible. Green laser beam also goes very further.
Although you also can select same output powered red or blue laser pointers, but none of other visible laser is more sensitive than 532nm green laser to human eyes. Thus 5mW green laser pointer is no doubt the number one choice as a stargazer. Available with portable pen design, astronomy laser pointer just allows continuous dot pointing at night with less than 30 seconds each time, and then cooling down about 10 seconds. The continuous wavelength green laser beam has just made super nice stargazing and constellation observation at night.