Block 1 Lesson 3

Structure of the Solar System

What is True FoV, how does it work

By putting on an eyepiece, the magnification will increase by a certain amount which is why there is an apparent FoV (what we see through the eyepiece) and a True FoV (the whole and true FoV of the telescope).

True FoV equation + unit

True FoV = Apparent FoV / Magnification

Unit = degree, arcmin, arcsec

Astronomical Unit (AU)

1.5 X 10”8 km (“8 = to the power of 8)

Light Year (l.y.)

9.5 X 10”12 km

Parsec (pc)

3.1 X 10”13 km

Astronomical unit → km

multiply by number of km

km → astronomical unit

divide by number of km

Write 1.6AU in km

1.6 X (1.5 X 10”8) = 2.4 X 10”8 km

You are multiplying the AU by the number of km there are in one AU which is 1.5 X 10”8.

Write 2.4 X 10”16 km in parsec

(2.4 X 10”16) / 3.1 X 10”13 = 7.74 X 10”2 pc

In this question you are dividing the number of km given to you (2.4 X 10”16) by the number of km in one parsec (3.1 X 10”13) to get the answer.

Properties of a telescope

• Large aperture objectives

• Large focal length

• Multiple mirrors

• Chromatic aberration

Large aperture objectives

Increasing this increases the resolution (how sharp or detailed the image is) of the telescope. Can be achieved by using tessellated mirrors (a mirror made of smaller segments = lighter and cheaper to make).

Large focal length

Increasing this increases the magnification the telescope is capable of.

Multiple mirrors

Using this increases the focal length without increasing the length of the telescope.

Chromatic aberration

Caused by different colour lights refracting by different amounts as they goes through the lens, causing blurred images or ‘mini rainbows’ to appear on the image.

Happens because of a dented or warped lens that creates a distorted image.

Are you familiar with this chart?

If not then study please :D

It might be given in exam but it’s good to be familiar with it anyways

Four types of meteors

Meteoroids, meteors, meteorite, micrometeorite

Meteoroids

• Found in space

• Size ranges from dust grains to small asteroids

• Mainly pieces of other larger bodies that have been broken or blasted off e.g. comets or asteroids

• Made of silicates, iron, nickel

Meteors

• When meteoroids enter a planet’s atmosphere at high speeds and burn up, the fireballs or ‘shooting stars’ are called meteors

• Basically meteoroids when they enter a planet’s atmosphere

• Composed of silicates, ferronickel, molten rock

Meteorites

• A rock that has crashed into Earth or a planet from above and has hit the ground

• Range in size from a pebble to a fist

• Composed of silicates and ferronickel

Micrometeorites

• Micrometer sized meteorites (too small to burn up in atmosphere, drift down to earth)

• More abundant and has a different composition

What is an elliptical orbit?

ELLIPTIC orbit = an oval shaped path like an elongated circle around an object in space that other object/s orbit around