Review of Telescope Lectures

Astronomy 25

1) Your eye is a small telescope of about _____ mm. aperture.

2) With large telescopes, the stars are more than just dots of light. (T/F)

3) An extended image (planet/galaxy etc.) is inverted each time its light reaches ______ in the telescope.

4) If this light is reflected off a mirror, _____ and _____ are swapped. (Look into a mirror for this one.)

5) Can the eye see an image at the telescope’s prime focus?

6) The eyepiece takes this light and _________ it for the eye.

7) Terminology:

a) Objective-

b) Secondary-

c) Aperture-

d) Focal length-

e) Focus-

f) F-number (f/#)-

g) Magnification (Calculated by)-

h) Apparent field of view-

i) True field of view-

8) A refractor uses a ______ ; a reflector uses a _______.

9) Underline the true conclusions (assume same eyepiece throughout.)

Larger objectives result in (brighter objects) (better resolution)

(more field of view) (greater magnification) (dimmer objects seen.)

10) Which star is brighter, 7^th magnitude or 10^th magnitude?

11) The dimmest star we can see on a good night with excellent vision is

______ magnitude.

12) Which is the least important characteristic of a telescope system?

13) A design characteristic of an eyepiece includes its ________ field of view.

14) Which eyepiece results in greater magnification, 12mm or 30mm?

15) The true FOV you see is a ratio of _________________ and __________.

16) Magnification is a ratio of _________________ and _______________.

17) Chromatic aberration is a problem with which kind of telescope?

18) Coma is a problem with (long / short) focal length telescopes.

19) Spherical aberration can be “focused” out. (T/F)

20) The worst aberration that no telescope escapes is poor __________.

21) Types of telescopes:

a) Straight-tube, “Captain Kidd” type, is a _______________ telescope.

b) Telescope with parabolic mirror at one end and eyepiece up near the other end, sticking out the side. (Invented by an Englishman.)

This is a ________________ telescope

c) Telescope by a French inventor that uses a secondary mirror to achieve a long focal length in a short body. Light emerges through a hole in the mirror.

This is a _______________ telescope.

d) A “correcting plate” invented by a German makes telescope c) into a

__________ - ___________ telescope.

e) A “correcting lens” invented by a Russian makes telescope c) into a

__________ - ___________ telescope. (This plate or lens is to correct

spherical aberrations inherent in telescope c).)

22) Which of the above becomes size-limited first?