# Questions tagged [notation]

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7 questions
1answer
86 views

### Superscript-subscript uncertainty notation

While reading publications in astrophysics I've encountered this kind of notation (fictitious example): $$M = 6.1^{+0.6}_{-0.1} \times 10^{30} \textrm{ kg}.$$ Several examples are here, p. 2. I ...
0answers
56 views

### Who first used two lambdas to typeset the wavelengths of a spectra line doublet?

Also what is the accepted or most common way to typeset the wavelengths of a doublet? e.g. lambdalambda-3727,3729 with or without a hyphen? and without the Angstrom symbol?
1answer
76 views

### What abbreviations, letters, or symbols do we use to denote highly degenerate stars?

We have OBAFGKM to denote the strength of hydrogen lines. Apparently we added S, N, C, and the W classes when we learned of new kinds of stars. We use T, L, and Y to denote brown dwarfs. The D ...
4answers
2k views

### Usage of $\sim$, $\approx$, $\simeq$, and $\cong$ in observational astronomy?

My understanding is $\sim$ generally means "on the order of magnitude of" e.g. $T \sim 10^5$ K $\approx$ is obviously "approximately equal to" so for example one might write $d \approx 400$ pc rather ...
1answer
55 views

### From Mean Moon to True Moon in an old procedural calendar

This is a follow-up to How to interpret this old degree notation? It is about an old calendar system which generates a luni-solar calendar with a procedural method, using a handful of calculations ...
2answers
114 views

### How to interpret this old degree notation?

I'm trying to follow the calculations in this paper on page 5 (see image below). The paper is describing traditional methods of calculation for a luni-solar calendar. The math is not hard, but I can'...
1answer
200 views

### Name and language of symbol in astronomy book

I've been working on a programming project involving Peter Duffett-Smith's Practical Astronomy With Your Calculator (3rd Ed.), which has a large number of mathematical/astronomical formulas in it. ...