Section 1: Introduction, flux, distance, magnitude, colour

Question 1

What is the equation for the luminosity of a star?

Answer 1

L=4πR_*²F

Question 2

What is the equation for parallax?

Answer 2

α=r/d
As sinα is very small

Question 3

What is the equation for calculating apparent magnitude?

Answer 3

m₁-m₂=-2.5log₁₀(f₁/f₂)

Question 4

What type are most telescopes?

Answer 4

Optical or radio

Question 5

Why must telescopes be a certain type?

Answer 5

Atmosphere block out most of the radiation spectrum

Question 6

What is a bandpass?

Answer 6

A filter to select a range of wavelengths

Question 7

What is the V-B colour?

Answer 7

m_V-m_B

Question 8

What is the B-V colour?

Answer 8

m_B-m_V

Question 9

What do the V-B and B-V colours represent?

Answer 9

If V-B>0 then the star is less blue than vega

Question 10

What is absolute magntiude?

Answer 10

The brightness of a star placed at a distance of 10 parsecs

Question 11

What is the equation for absolute magnitude?

Answer 11

M-m=-5log₁₀(d/10pc)

Question 12

How do magnitudes scale?

Answer 12

A lower magnitude represents a brighter star

Question 13

What is the total solid angle in a unit sphere?

Answer 13

4π

Question 14

What are the units of the solid angle?

Answer 14

Steradians

Question 15

What is the equation for solid angle?

Answer 15

Surface area hit/ Total possible area