This is very unlikely to be practical in any way. Just ask yourself how many times you've seen a lightbulb in the last five years. Sure, you've seen plenty of light fixtures, lots of neon tubes, some LED bulbs, etc, but an old fashioned light bulb, not enclosed in any type of lamp shade?

That aside, how are you going to discretely point a telescope at the light bulb from a distance of 25 meters? You might as well point a parabolic microphone at them and get a better signal.