From our ground-based point of view, space is observed through the Earth’s atmosphere. The atmosphere has a direct effect on the quality of what we are observing. To obtain the best views, astronomers keep a close eye on weather and atmospheric conditions, phase of the Moon, sunrise and sunset times, and twilight timeframes.
We obviously want the skies be free of clouds, or at least free of clouds in the region of the sky that we wish to observe. Stable and dry atmospheric conditions help provide more detailed views. Moonless nights ensure the bright moonlight does not wash out subtle details and dimmer objects.
There are several websites astronomers can rely on to obtain information about atmospheric conditions, moon phases, and more. We have embedded a few in this webpage for regular reference.