[Ralph Davey (Ralph)]

Hi there,

Haven't posted in this section of the ice in space forum yet, and apologies in advance as my only other thread was about a question I had as well. Anyway, I'm returning to study next year to study astronomy and have been trying to get a head start. Hopefully after that I will be able to assist others who are in a similar situation to myself at the moment! Being an amateur astronomer for quite some time, I have a decent understanding of general astronomy theory, however spectroscopy/radio astronomy have always been my most neglected areas!

My question is related to the terminology used with what seems to be involved with transitions! I understand the basics of spectra, however more advanced texts tend to mention J and K and always have bracketed numbers next to them eg J, K (1,1) or (1,3) etc. Its hard to find any information that bridges the gap between a general astronomy spectra that talks about basics and more advanced texts. So my problem being is that basic texts avoid going this deep, and advanced texts seem to assume that the reader understands what J and K equal, and what the numbers relate to (I've got a fair idea, but a solid answer would be great).

Could anyone please explain this, or please suggest an appropriate resource so I could understand this aspect of spectra science?

Thanks in advance.

Best,
Ralph