Segmented mirrors sag under their own weight. Their optical shape ...

[kellyjaisingh]

Segmented mirrors sag under their own weight. Their optical shape must be controlled by computer-driven thrusters under the mirrors in what is called
 
  a. an achromatic lens.
  b. active optics.
  c. a Schmidt-Cassegrain design.
  d. a Newtonian design.
  e. interferometry.

Question 2

If the stars at the turnoff point of a cluster have a mass of 3 M, what is the age of the cluster?
 
  a. 3.0 x 1010 years
  b. 3.3 x 109 years
  c. 6.4 x 108 years
  d. 1.6 x 1011 years
  e. The age of a star cluster can not be determined from the mass of stars at the turnoff point.

[momtoalll]

Answer to Question 1

B

Answer to Question 2

C