Be stars

Be stars

Be stars Recommended equipment : Lhires III, eShel, Lisa, Alpy Time : one evening to a life time ! Abstract Classical Be stars are non supergiant B-type stars that exhibit or have exhibit emission lines over the photospheric spectrum. This article review common...
Measure star temperature

Measure star temperature

Measure star temperature Recommended equipment : Lhires III, eShel, Lisa, Alpy, Star Analyser Time : 4h French philosopher Auguste Compte (1798-1857) became very famous when he wrote in 1835 about stars: “… we will never know, by any mean, chemical...
Atmospheric sodium

Atmospheric sodium

Atmospheric sodium Recommended equipment : Lhires III, Lisa , Alpy Time : about 1h  (at sunset) 80km above our head is an atmospheric layer with sodium excited by our Sun. During the day, it is not visible as the solar spectrum is too bright. During the night, this...