Ursa Major in colours

Here at a glance are the shades of all the stars within the sixth magnitude of Ursa Major, one of the most popular constellations in the celestial vault.

Beyond magnitude +5, one notices that among the bright blue stars that draw the Big Dipper asterism are scattered many other fainter yellow and orange stars, scattered as far as the neighbouring constellations of the Dragon and the Hounds.

There are over 110 stars, that is, all those potentially observable with the naked eye under a dark sky. Photographed one by one deliberately out of focus as they appear to the eyepiece of an 18-inch Dobson at 285 magnifications to better highlight their opaque hues and placed on a scale according to apparent magnitude.

They can represent - in the various colour gradations - almost all the best-known spectral classes.

Here are the colours of Callisto, nymph turned into a bear by Hera after Zeus' betrayal. They seem to be the last trace of the beauty that had seduced Zeus and that Hera had tried to hide under the guise of a bear, yet remained forever engraved in these shades, as well as in her name.

Dobson telescope 18" and smartphone A5

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