Star/Planet Visual Magnitude & Angular Size

Jupiter
Mars
Capella
Betelgeuse
Aldebaran
Pollux
Castor
Uranus




-2.3
-0.70
0.24
0.50
1.0
1.29
1.58
5.7



40.7 ∠ "
12.4 ∠ "





3.6 ∠ "






--- Star Visual Magnitude Scale--- 
Brightest Star: Sirius α Cma -1.44
Faintest Star Magnitude: 6.0  (dark sky, average good eyesight)
Brightness Difference for magnitude step of 1: 5√100 ~ 2.512 


 --- Angular Resolution --- 
Dawes' Angular Resolution Limit in ∠ " for a perfect lens of diameter d(mm):
Res = 116/d(mm)

Human Eye (dark adapter) ~ 60 ∠ " = 1 ∠ '  ~ 0.02 ° 
50mm Lens:  2.3 ∠ " 
100mm Lens: 1.2 ∠ " 
8" Telescope (203mm)  0.57 ∠ "