See the list of other virtual experiments. Note the apparent magnitude and spectral type of Sirius A as noted in the data window. Use the Apparent Magnitude and calculated distance for Sirius A to determine the Absolute Magnitude using Equation 6 . Plot the location of Sirius A on an H-R diagram. Some advanced amateur astronomers can roughly estimate apparent magnitude by looking at a star in the night sky.
Accurate measurements require a photometer or a CCD camera telescope attachment.
Parallax measurement mode scales the size of the star, based on its apparent magnitude from earth. Note that Perspective project mode scales it relative to the apparent magnitude as observed from deep space.