The area of our galaxy that we are going to use is called the North American Nebula. It’s a star field at a distance of around 1000 light years.
© T. Credner & S. Kohle, AlltheSky.com
Place: Hoher List observatory, Observer: T. Credner
Of course it is not going to be posible to count all the stars in the field
quickly so were going to look at just a tiny area of the field one square
arc minutes or 1/60 of a degree. Click
here to view the sample were going to use.
We know that the star field is 1000 light years away and that the Andromeda
galaxy is around 2,000,000 light years away this means that Andromeda is 2000
times farther away. One arc minute covers an area 4,000,000 times larger in
a picture of the Andromeda galaxy than it does in the star field picture.
So it should contain 4,000,000 times more stars.
How many stars would Andromeda have in a square arc minute?