Angles and Parallax Flashcards
1
Q
How many arcminutes are in 1 degree?
A
60
2
Q
How many arcseconds are in 1 arcminute?
A
60
3
Q
How can we find the length of a far away object?
A
Using parallax and small angle approximation
l=αd (roughly)
Where α is the angle subtended by the object and is in radians
4
Q
What is a parsec?
A
d(pc)=1Au/p
Where p is the parallax in arcseconds
1pc=3.26ly
5
Q
How do we measure parallax?
A
Measure the distance of the object against a fixed background at two different times 6months apart
Then d=R_E/p
5
Q
What is proper motion?
A
That precision stars are not fixed as they have their own motions relative to the Sun
