Naked eye astronomy

Question 1

Observations of the Sun, Moon, nearby planets and stars can tell us a lot about what?

Answer 1

any celestial bodies and phenomena can be observed without specialist equipment. Observations of the Sun, Moon, nearby planets and stars can tell us a lot about the nature and movement of objects in the solar system and beyond.

Question 2

which planets can be seen with the naked eye?

Answer 2

The nearest planets can be seen with the naked eye. They are Mercury, Venus, Mars, Saturn and Jupiter.

Question 3

what is retrograde motion?

Answer 3

The planets sometimes appear to move with retrograde motion. This is when the planets appear to slow down or go in reverse, relative to the positions of distant ‘fixed’ stars.

Question 4

what is the sun’s movement across the sky?

Answer 4

The Sun rises in the east and sets in the west, moving across the sky during the day.

Question 5

How long does It take the Sun to move from its highest points to its next highest point ?

Answer 5

It takes 24 hours for the Sun to move from its highest point in the sky (at noon) back to its highest point the following day.

Question 6

How long does it take the stars to move across the sky from east to west?

Answer 6

The stars to move across the sky from east to west, but they take slightly less than 24 hours. The Moon takes slightly longer than 24 hours to apparently move across the sky in the same direction.

Question 7

How long does The Moon takes to apparently move across the sky in the same direction east to west ?

Answer 7

The Moon takes slightly longer than 24 hours to apparently move across the sky in the same direction.

Question 8

why will different stars be visible from a position on Earth at different times of the year?

Answer 8

Because the Earth orbits the Sun, different stars will be visible from a position on Earth at different times of the year.

Question 9

Phases of the Moon - what is the linear cycle?

Answer 9

The Moon’s appearance changes during its 28-day orbit of the Earth. This is called the lunar cycle. This can be explained by considering the way that sunlight falls on the moon as it changes its position around the Earth.

Question 10

what is a new moon.

Answer 10

When the Sun is effectively behind the Moon, the side of the Moon that faces the Earth is in shadow - this is called a new moon.

Question 11

what is full moon

Answer 11

When the side of the Moon that faces the Earth is fully illuminated by the Sun, this is called a full moon

Question 12

what is a Solar eclipse?

Answer 12

A solar eclipse happens when the Moon passes directly between the Sun and the Earth - on the same line - casting a shadow of the Moon on the surface of the Earth. This would happen during the new moon phase of the lunar cycle.

Question 13

what is a total eclipse?

Answer 13

If the Moon completely obscures the Sun (when viewed from Earth), it is called a total eclipse.

Question 14

what is a partial eclipse?

Answer 14

If the Moon partially obscures the Sun, it is a partial eclipse.

Question 15

Why is vViewing solar eclipses with the naked eye very dangerous – it can burn your retina and lead to permanent damage to your eye.

Answer 15

it can burn your retina and lead to permanent damage to your eye.

Question 16

what is a safe way to look towards the sun ?

Answer 16

a safe way to look towards the sun is to use a pinhole viewer. If you make one do not look through the pinhole, only look at the image made on the paper.

Question 17

what is a Lunar eclipse?

Answer 17

A lunar eclipse occurs when the Earth passes directly between the Sun and the Moon, casting a shadow of the Earth on the surface of the Moon. This would happen during a full moon.

Question 18

How can the position of astronomical objects be plotted?

Answer 18

The position of an astronomical object can be plotted with two angles, relative to a point on the Earth.

Question 19

What is the angle of declination? What does a positive angle of declination mean?

Answer 19

The angle of declination refers to whether the object is above or below the line of the equator. A positive angle of declination means that the object will be seen more clearly from a position in the Northern hemisphere.

Question 20

what is the angle of right ascension?

Answer 20

The angle of right ascension refers to the measurement of the angle east from the vernal equinox point (measured in degrees and minutes).

Question 21

what is a solar day ?

Answer 21

A solar day is the time taken for the Sun to move from its highest point in the sky back to its highest point the following day. This is exactly 24 hours.

Question 22

what is a sidereal day ?

Answer 22

A sidereal day is the time it takes for the Earth to actually rotate once on its axis. A sidereal day is four minutes shorter than a solar day.

Question 23

why is the sidereal day shorter than the solar day ?

Answer 23

The sidereal day is shorter than the solar day because as well as rotating on its axis, the Earth also orbits the Sun.

Question 24

why do Solar eclipses not occur every month during the new moon ?

Answer 24

Solar eclipses do not occur every month during the new moon because the Moon does not orbit the Earth in exactly the same plane as the Earth orbits the Sun

Question 25

The path that the Sun traces across the sky is called the what ?

Answer 25

The path that the Sun traces across the sky is called the ecliptic.

Question 26

what is the ecliptic plane?

Answer 26

the plane in which the Earth orbits the Sun is called the ecliptic plane.

Question 27

During most of the new moons in a calendar year, where is the Moon?

Answer 27

During most of the new moons in a calendar year, the Moon is either above or below the ecliptic plane. A solar eclipse can only occur when the Moon passes through the ecliptic plane during a new moon.

Question 28

Can a solar eclipse only occur when the Moon passes through the ecliptic plane during a new moon?

Answer 28

yes

Question 29

How often do solar eclipses occur somewhere on Earth ?

Answer 29

Around 2-5 solar eclipses occur somewhere on Earth every year

Question 30

A total eclipse will occur how often?

Answer 30

total eclipses are rare - . A total eclipse will occur approximately once every 18 months.

Question 31

Because the stars are so far away, their positions in the celestial sphere on a day-to-day timescale can be taken to be what?

Answer 31

Because the stars are so far away, their positions in the celestial sphere on a day-to-day timescale can be taken to be approximately constant, or ‘fixed’.

Question 32

Why do stars appear to move across the sky from east to west ?

Answer 32

Stars appear to move across the sky from east to west because of the rotation of the Earth.

Question 33

what is retrograde motion?

Answer 33

However, the movement of the planets against the background of relatively static stars is more complicated. Sometimes the movement of a planet seems to slow down or go into reverse. This is called retrograde motion.

Question 34

How can retrograde motion be illustrated using Venus, ?

Answer 34

This can be illustrated using Venus, which is closer to the Sun than Earth, so it orbits more quickly. When Venus is on the same side of the Sun as the Earth (position 1), it appears to move in one direction against the stars. However, when Venus is on the other side of the Sun (position 2), it appears to be travelling in the other direction