Comet Hale-Bopp

This task is about reading star maps.
The position of the comet Hale-Bopp is shown relative to background stars.
The observer would be looking in a North-West direction one hour after sunset.
 

Question 1Change answer

a)  Why is the position of the comet Hale-Bopp changing in the night sky?

Question 1Change answer

b)  The stars are 'setting' four minutes earlier each night. On June 1, Aldebaran will have 'set' and Bellatrix will be just above the horizon.
Name another star that will remain visible in the night sky.

Question 1Change answer

c)  Explain why the comet would not be seen by an observer from this location until May 1997.