PHYS 150 - Astronomy Hour Test 1- Samford University

deci (d)

10^-1

centi (c)

10^-2

milli (m)

10^-3

micro (m)

10^-6

nano (n)

10^-9

deka (da)

10^1

Tera (T)

10^12

hecto (h)

10^2

kilo (k)

10^3

mega (M)

10^6

Giga (G)

10^9

Gregorian Calendar

365 days per year, however. The period of revolution of the earth is 365.2415 days. To account for the .2425 fractional day, every fourth year an extra day (Feb. 29) was added to the year. A year is a leap year if it is divisible by 4. A century year is a leap year if it is divisible by 400. For example, 1600 and 3000 are leap years, but 1700 and 1800 are not.

Constellation

A configuration of stars in the same region of the sky. (Ch. 2)

Celestial equator

A great circle on the celestial sphere 90 degrees from the celestial poles (Ch. 2)

Powers of ten (scientific) notation

A shorthand method of writing numbers, involving 10 followed by an exponent. (Ch. 1)

Celeste sphere

An imaginary sphere of very large radius centered in an observer; the apparent sphere of the sky. (Ch. 2)

Declination

Angular distance of a celestial object north or south of the celestial equator. (Ch. 2)

Diurnal motion

Any apparent motion in the sky that repeats on a daily basis, such as the rising and setting of stars. (Ch. 2)

Worst time to view superior planet?

Conjunction

SI basic unit for temperature

Kelvin (K)

SI basic unit for mass

Kilogram (kg)

Totality

Lunar: the period during a total lunar eclipse when the moon is entirely within earth's umbra Solar: the period during a total solar eclipse when the disk of the sun is completely hidden (Ch. 3)

Superior Planets

Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto

Lepus

Orion Family Hare

Orion

Orion Family Hunter

Canis Major

Orion Family Larger Dog

Canis Minor

Orion Family Smaller Dog

Monoceros

Orion Family Unicorn

Ecliptic

The apparent annual path of the sun on the celestial sphere. (Ch. 2)

SI Units

The international system of units, based on the meter (m), the second (s), and the kilogram (kg). (Ch. 1)

Autumnal equinox

The intersection of the ecliptic and the celestial equator where the sun crosses the equation from the north to south. Also used to refer to the date on which the sun passes through this intersection. (Ch. 2)

Ecliptic plane

The plane of earths orbit around the sun. (Ch. 2)

North celestial pole

The point directly above earths north pole where earth;s axis of rotation, if extended, would intersect the celestial sphere (Ch.2)

Vernal equinox

The point in the ecliptic where the sun crosses the celestial equator from south to north. Also used to refer to the date on which the sun passes through this intersection. (Ch. 2)

Sagittarius

Zodiacal Family Archer

Taurus

Zodiacal Family Bull

Cancer

Zodiacal Family Crab

Pisces

Zodiacal Family Fish

Leo

Zodiacal Family Lion

Aries

Zodiacal Family Ram

Libra

Zodiacal Family Scales

Scorpius

Zodiacal Family Scorpion

Capricornus

Zodiacal Family Sea Goat

Gemini

Zodiacal Family Twins

Virgo

Zodiacal Family Virgin

Aquarius

Zodiacal Family Water Carrier

right ascension

a coordinate for measuring the east-west positions of objects on the celestial sphere (Ch 2)

waning gibbous of lunar phases

all but sliver of moon showing

waxing gibbous of lunar phases

all but sliver of moon showing

full moon of lunar phases

all of moon visible

Lunar eclipse

an eclipse of the moon by earth; a passage of the moon through earth;s shadow (Ch. 3)

Solar eclipse

an eclipse of the sun by the moon; a passage of death through the moon's shadow (Ch. 3)

annular eclipse

an eclipse of the sun in which the moon is too distant to cover the sun completely so that a ring of sunlight is seen around the moon at mid-eclipse (Ch.3)

When are superior planets farthest from Earth?

conjunction

Best time to view inferior planet?

greatest elongation east or west

third quarter of lunar phases

half of moon

first quarter of lunar phases

half of the moon

When are inferior planets closest to Earth?

inferior conjunction

Worst time to view inferior planet?

inferior or superior conjunction

second contact of solar eclipse

just when the moon completely covers the sun - beginning of totality

forth contact of solar eclipse

just when the moon completely uncovers the sun

third contact of solar eclipse

just when the moon starts to uncover the sun - end of totality

Sidereal Time

measured with respect to the stars, defines a day as the time it takes the earth to complete one full rotation on the axis with respect to the sun and to the stars. day = solar day - 3 min 56 sec ~ 23h 56 m

Solar Time

measures with respect to the sun, defines a day as the time it takes the earth to complete one full rotation on the axis with respect to the sun and to the stars. the earth must rotate more that 360 degrees. This is because the earth progresses in its orbit about the sun and extra rotation is needed to compensate for this progression.requires an additional 3 minutes 56 seconds more than a sidereal day day = 24 hours

inferior planets

mercury, venus

SI basic unit for length

meter (m)

New moon of lunar phases

no moon visible

Best time to view superior planet?

opposition

When are superior planets closest to Earth?

opposition

SI basic unit for time

second (s)

waning crescent of lunar phases

sliver of moon

waxing crescent of lunar phases

sliver of moon

When are inferior planets farthest from Earth?

superior conjunction

Umbra

the central, completely dark portion of a shadow (Ch. 3)

sidereal period

the orbital period of one object about another as measured with respect to the stars (Ch. 4)

Synodic month

the period of revolution of the moon with respect to the sun; the length of one cycle of lunar phases. also called the lunar month (Ch. 3)

Sidereal month

the period of the moons revolution about earth with respect to the stars (Ch. 3)

South celestial pole

the point directly above earths south pole where earth's axis of rotation, if extended, would intersect the celestial sphere (Ch.2)

apogee

the point in its orbit where a satellite or the moon is farthest from earth (Ch. 3)

perigee

the point in its orbit where a satellite or the moon is nearest earth (Ch.3)

summer solstice

the point on the ecliptic where the sun is farthest north of the celestial equator. also used to refer to the date on which the sun passes through this point. (Ch. 2)

winter solstice

the point on the ecliptic where the sun reaches its greatest distance south of the celestial equator. also used to refer to the date on which the sun passes through this point. (Ch. 2)

Penumbra

the portion of a shadow in which only part of the light source is covered by an opaque body (Ch.3)

eclipse path

the track of the tip of the moon's shadow along earth's surface during a total or annular solar eclipse (Ch.3)

First contact of solar eclipse

when the moon just begins to cover the sun