Sirius A and its faint companion, Sirius B. Credit: Hubble Space Telescope/NASA/ESA,H. Bond (STScI) and M. Barstow (University of Leicester).
A prime application of the historical method concerns the colour of Sirius A or α Canis Majoris, the brightest star in the night sky. Sirius appears bright white today, but – as the English amateur astronomer, Thomas Barker (1722-1809), first pointed out in 1760 – was emphatically qualified as red in many classical texts. Poetical passages aside, Seneca commented that Sirius was of a deeper red than Mars, while Ptolemy labeled the star “reddish” and grouped it with five other stars, all of which are indeed of red or orange aspect.
