Star Wheel? Planisphere kya hai?

Every night we can see more than 300 degrees of the night sky. 

Since the Sun moves at 15degrees per hour, so for 2 hours after sunset and 2 hours before sunrise you can't see stars.

so that is 30 degrees (2hours x 15 degrees) after sunset and 30 degrees before sunrise, of the sky sphere when stars aren't star like, Bright. 

So if you see the night sky through out the night you can say you have travelled across galaxies!