Sodium in all its states !

Recommended equipment : Lhires III, eShel

Time : 1h

Sodium element has a nice spectral signature with two narrow lines in the yellow. Those lines, D1 & D2, are at wavelength 589.00nm and 589.59nm, split by about 6 angstroems only.

You can get a hint of this doublet amission lines in street lamps as several of them, based on sidium, display a yellow color. The same color appears when you throw salt (which contains sodium) on a candel flamme. But you can also see the same doublet in numerous stars.

Following observation of D1/D2 sodium doublet have been done with a Lhires III spectrograph and a digital SLR. With its 2400 lines/mm grating, Lhires III resolution is spliting the doublet widely !