1
vote
1answer
41 views

Relation between red filter band and redshift?

I am interested in knowing what is the significance of red filter band in the study of redshift dependence of spatial orientation of galaxies?
1
vote
0answers
231 views

How to find orbital radius of star in a binary system using redshift and orbital period data? [duplicate]

Possible Duplicate: About binary stars and calculating velocity, period and radius of their orbit I am given the non-redshifted wavelength of the EM radiation from one of the stars, the ...
4
votes
2answers
1k views

How do you measure distance to stars within the galaxy?

I know that for close by stars (<50 LY) we can use the parallax effect. And for distant galaxies we use red-shift (& hubble's constant). So how do we measure how far is a star lets say 50,000 ...