ASTRONOMY 5 THIRD HOUR SESSION “E” NAME KEY-E ACTIVITY:  Introduction to Telescopes and Binoculars DATE ID#

1.  List the three ‘powers’ of  a telescope discussed in class.

 Magnification Light Gathering Resolving

2.   What is the highest magnification power of the three four binoculars displayed in class?

 25x (Binos C)

3.  Which of the above mentioned binoculars has the greatest light gathering power (LGP) (A, B, or C or D)?

 D (20x80)

4.   What is the light gathering power of binocular _A_ (from question 3),  compared to your eye (Do = 7 mm)?

 (35/7)2  = 25x

5.   What is the magnification you would get with the eyepiece in the refracting telescope displayed at the front of the lab?

 1200/9 = 133.3 (±1)

6.   What is the magnification you would get with the eyepiece in the reflecting telescope displayed at the front of the lab?

 750/25=30 (±1)

7.   How much (times) more light gathering power does the telescope with the largest objective displayed have in comparison to one of the objective lenses of binocular __B__ from question 3?

 (150/50)2 = 9x

8.    Is a ___8___mm eyepiece an acceptable choice in a telescope with an objective focal length (F0) of  _1200_mm and an objective diameter (D0) of __120__mm ?

 Yes, the telescope can support such a high mag (limit 120*2 =240x)

9. If a pair of binoculars has a Field of View (FOV) of ___5__° and  a telescope with a particular eyepiece has a FOV of 0.5°, which will give the best view of the Beehive Cluster which has an angular size of 1.5°?  Which will give he best view of the globular star cluster M13 which has an angular size of 20'?

 binoculars telescope

10.  For a given telescope, which eyepiece willl give a __smaller_____ Field of View - Fe =  __20_ mm or Fe = __26_ mm?

 20 mm