Stars Deneb, Vega, and Altair form an isosceles triangle and they are called isosceles triangle pointing south. The isosceles triangle changes in direction with the change in season and just in 3 hours, so fast forward three hours they will remain pointing south only. Deneb, Vega and Altair are the brightest stars of the constellation.
The question is asking to describe and state and calculate what do the observer on the earth measure for the speed of the laser beam, and base on my research, the answer would be v = 1bc, I hope you are satisfied with my answer and feel free to ask for more
