In the former case, values based on right ascension and declination are obtained.
This was used for measuring the right ascension of the stars.
Look at the second sketch, the one with "right ascension" across the top and "light-years" down the side.
However, this particular set of stars was chosen because they are divided on the sky by approximately 6 hours apart in right ascension.
It is located at right ascension 16 41.7 and declination +36 28'.
By it the right ascension and the declination of a star may be measured in a single observation.
Unlike right ascension, hour angle is always increasing with the rotation of the Earth.
Maps of the stars in the night sky use declination and right ascension as coordinates.
The galactic longitude increases in the same direction as right ascension.
It has a right ascension of 15h 36.5m and a declination of 16 36'.