The first description of the Andromeda Galaxy based on telescopic observation was given by Simon Marius in 1612, and Charles Messier catalogued it as object M31 in 1764. In 1785, the astronomer William Herschel noted a faint reddish hue in the core region of the M31. He believed it to be the nearest of all the great nebulae and, based on the color and magnitude of the nebula, he wrongly estimated that it was no more than 2,000 times the distance of Sirius. In 1864, William Huggins observed that the spectrum of M31 differed from a gaseous nebula. The spectra of M31 displayed a continuum of frequencies, superimposed with dark lines. This was very similar to the spectra of individual stars. From this it was deduced that M31 had a stellar nature and, therefore, that it was a galaxy.