midterm 1 Flashcards
what are the two dimensions of the equatorial coordinate system?
right ascension, declination
What is the imaginary sphere of stars around the earth called?
Celestial sphere
what is the declination of the North Celestial Pole?
90deg N
What are the units of declination
degrees
What are the units of right ascension
hours/minutes
Define Zenith
Point directly overhead
Define Nadir
Point directly underneath
Define the observer’s meridian
The arc that runs from the north point of the horizon through the zenith and down to the south point
Name the two angles of coordinates in the horizon coordinate system
Azimuth, altitude
Define Azimuth
Compass direction of star in degrees
Define altitude
angle that the object is above the horizon
Define Ecliptic
The apparent motion of the sun around the celestial sphere
Name the four equinoxes
Vernal, Summer, Autumnal, Winter
List the four dates of the equinoxes
Mar 21, Jun 21, Sep 21, Dec 21
name the 3 types of teliscopes
refractor, reflector, catadioptric
name the advantages of a refractor telescope
long focal length=large image,
describe the disadvanges of a refractor telescope
need a counterweight, require large domes, lens have a limiting size, chromatic aberration
Name the two focal arrangements of reflector telescopes
Newtonian, Cassegrain
name advantages of reflector telescopes
no chromatic abberation, no size limit, shorter tubes
what does a catadioptric use to focus light?
mirrors, and lens
define resolving power
the ability to separate fine detail and distiguish objects
what is the resolving power proportional too
The aperature
define aperature
the diameter of the objective
define light gathering power
amount light collected
