Chapter 3-The Celestial Sphere

Question 0

Gnomon

Answer 0

An object that projects a shadow that can be used to indicate the time of day or the time of year.

Question 1

Constellation

Answer 1

An area of the sky.

Question 2

Quadrant

Answer 2

90 degree arc

Question 3

Refractor Telescope

Answer 3

A telescope that uses only lenses to concentrate the light from an object and focus it into an image.

Question 4

Refraction

Answer 4

Bending of light.

Question 5

Objective lens

Answer 5

• The lens that points to the object.

* The light-gathering lens.

Question 6

Ocular (eye piece)

Answer 6

The magnifying lens.

Question 7

Resolution

Answer 7

The ability of a telescope to bring out details in an image.

Question 8

Wave length

Answer 8

The horizontal distance from one wave crest to the next wave crest.

Question 9

Compound lens

Answer 9

2 or more lenses made of different kinds of glass mounted together to correct for chromatic aberration.

Question 10

Reflector Telescope

Answer 10

A telescope design that uses a concave mirror as the primary light-gathering optical component.

Question 11

Newtonian reflector

Answer 11

A telescope in which light from an object is collected by a concave mirror mounted at the bottom of a ridge tube, reflected to a small diagonal mirror near the top of the tube, and then reflected out through the side of the tube to the eye piece.

Question 12

Cassegrainian reflector

Answer 12

A compact form of reflector telescope in which the sky is viewed from behind the main mirror.

Question 13

Composite telescope

Answer 13

A telescope that uses both a primary mirror and a large objective corrective lens as the main light-gather elements of the telescope.

Question 14

Schmidt-Cassegrainian

Answer 14

A composite telescope that uses a spherical concave main mirror and a spherical convex secondary mirror arranged according to the Cassegrainian design but also includes an aspherical correction plate that both eliminates the spherical aberration in the mirror system and supports the secondary mirror.

Question 15

Radio telescope

Answer 15

A radio receiver with a large, dish-shaped antenna system.

Question 16

Hubble Space Telescope (HST)

Answer 16

An astronomical reflecting telescope placed in Earth orbit by the space shuttle in 1990.

Question 17

Coordinates

Answer 17

Astronomical equivalent of latitude and longitude.

Question 18

Celestial Equator

Answer 18

The plane of the earth’s equator projected into the sky.

Question 19

Declination (DEC)

Answer 19

A start’s angular distance north or south of the celestial equator.

Question 20

Right Ascension (RA)

Answer 20

A star’s longitudinal position.

Question 21

Prime Hour Circle

Answer 21

The starting line for right ascension.

Question 22

Magnitude

Answer 22

A way to measure star’s brightness.

Question 23

Red Shift

Answer 23

A mathematical rule that relates the stretching of wavelengths of their light with increasing distance.

Question 24

Proper motion

Answer 24

Movement across the sky as we see it.

Question 25

Radial motion

Answer 25

Movement directly toward or away from us.

Question 26

Temperature

Answer 26

The color of a star (is the result of surface temperature).

Question 27

Supergiant

Answer 27

A red star 500 times larger than the sun.

Question 28

White dwarf

Answer 28

A blue-white star that is relatively small.

Question 29

Density

Answer 29

The amount of matter (mass) contained in a single volumetric unit of a substance.

Question 30

Eclipsing Binary

Answer 30

2 stars revolving around each other such that they periodically pass in front of each other relative to the observer.

Question 31

Cepheid variable

Answer 31

A type of star that changes in brightness regularly.

Question 32

Period

Answer 32

In general, the length of time it takes a repeating events to occur.

Question 33

Nova

Answer 33

A star that explodes and increases in brightness up to ten magnitude but is not destroyed in the process.

Question 34

Supernova

Answer 34

A star that suddenly increases its apparent brightness by about 20 magnitudes because of an explosion that essentially destroys it.

Question 35

Neutron star

Answer 35

A small extremely dense star, dark starlike object made of neutrons.

Question 36

Star cluster

Answer 36

A group of stars that appear to be relatively close to each other and have the same radial and proper motions.

Question 37

Galaxy

Answer 37

A collection of millions of stars that are arranged in a variety of patterns around a gravitational center.

Question 38

Nebula

Answer 38

A cloud of of gas and dust in outer space.

Question 39

Quasar

Answer 39

An unusually bright celestial object that produces strong radio emissions.

Question 40

Black hole

Answer 40

A small object or region in space with gravity so intense that it is believed that matter, energy, and even light cannot escape from within its boundaries.