Chapter 2

Question 1

Apparent solar time

Answer 1

keeping time according to the position of the sun in the sky

Question 2

Autumnal equinox

Answer 2

point the sun crosses the celestial equator and has 0 declination

Question 3

Celestial equator

Answer 3

90 degrees from both poles. divides the sky into north and south

Question 4

Conjunction

Answer 4

when a planet is nearly aligned with the sun

Question 5

Declination

Answer 5

a north south coordinate equal to the angular distance of a star from the celestial equator

Question 6

Direct motion

Answer 6

see prograde

Question 7

Diurnal

Answer 7

daily

Question 8

Diurnal circle

Answer 8

the path a star appears to follow

Question 9

Ecliptic

Answer 9

path sun follows among the stars

Question 10

Equatorial system

Answer 10

a coordinate system similar to earth for the sky

Question 11

leap years

Answer 11

adding an extra day once every four years

Question 12

local hour angle

Answer 12

angular distance westward around the celestial equator from the meridian to the point on the equator nearest the star

Question 13

mean solar time

Answer 13

average solar time classic 24hr days.

Question 14

meridian

Answer 14

the line that passes through both celestial poles and the zenith and divides the sky into east and west

Question 15

nodes

Answer 15

points of intersection between the ecliptic and the moons orbit

Question 16

opposition

Answer 16

when a planet is opposite of the sun

Question 17

prograde motion

Answer 17

planet moves eastward

Question 18

retrograde motion

Answer 18

that time when the planets motion eastward appears to reverse westward

Question 19

right accension

Answer 19

angular distance measured eastward along the celestial equator from the vernal equinox

Question 20

sidereal clocks

Answer 20

used to keep track of the vernal equinox. o hours when the vernal crosses the meridian 24 when it returns to the meridian

Question 21

Sidereal day

Answer 21

length of time it takes a star to return to the meridian

Question 22

Sidereal month

Answer 22

time it takes the moon to return to the same place among the stars

Question 23

Summer solstice

Answer 23

point on the ecliptic where the sun is most northernly

Question 24

synodic month

Answer 24

length of time it takes the moon to return to the same position relative to the sun.

Question 25

Synodic period

Answer 25

interval of time between episodes of retrograde motion

Question 26

tropical year

Answer 26

length of time it takes the sun to return to vernal equinox

Question 27

vernal equinox

Answer 27

position of the sun on the celestial sphere on the first day of spring

Question 28

Winter solstice

Answer 28

point on the ecliptic where the sun is most southernly

Question 29

year

Answer 29

365 days