I did some research. The sky contains 88 internationally recognized constellations. Two dozen constellations are visible at any time of the year. Stars twinkle in the night sky because of atmospheric turbulence, such as when a front passes through, and the flow of air is disturbed. To help understand the twinkling patterns in the nighttime sky, you first need to know the principles of movement, magnitude and orientation.
Stars rise four minutes earlier every day, as seen from a given observation point.
Over the course a month, this amounts to a two-hour difference in the way the sky looks at a specific time. It takes a year for stars to make a full rotation, so the night sky would look identical to you if you were standing in the same spot next June 20 at 8 p.m. as you were this year on June 20 at 8 p.m. The degree of brightness of individual stars, known as magnitude, is rated from 0 to 6, with each step representing a difference of roughly 2.5 times the amount of light reaching your eye. The brightest stars have a magnitude of 0 and 1 and are known as first-magnitude stars. The sky contains only 21 of these stars and they are easy to locate even in an urban setting.