Formulas you might have to know...

Question 1

Explain the declination formula:

Answer 1

Declination > 90 - latitude

This used to see if a star is circumpolar or not. If so, the stars declination will be greater than 90 - the observer’s latitude

Question 2

What is the formula for EOT?

Answer 2

EOT = AST - MST

Question 3

Explain Kepler’s Third Law:

Answer 3

T^2 = R^3

T = the time of one orbital period in earth years

R = mean distance from the sun in AU

Question 4

Explain how to use Kepler’s Third Law:

Answer 4

To work out R:
Square T, then cube root than answer

To work out T:
Cube R, then square root the answer

Question 5

Explain how to work out the absolute mag of a star:

Answer 5

M = m + 5 - 5log(d)

M - absolute mag
m - apparent mag
d - distance to the star in parsecs

Question 6

Explain Hubble’s constant formula:

Answer 6

V = Hd

V - recessional velocity of a galaxy in km/s

H - hubble’s constant (77km/s/Mpc)

d - distance to the galaxy

Question 7

How do you work out the age of the universe using Hubble’s constant?

Answer 7

Convert the units of the Hubble constant into seconds and do 1 over H