# 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. There's a part at the end of the book for symbols and abbreviations, which contains this:

After doing some Google-fu, I was unable to find the name of the symbol. Would anyone smarter than me (which should be quite a few of you... heck, quite a lot) know what this is? Hopefully there's Unicode for it...

This is a variant of pi, or "pomega".

In LaTeX, you can get it by using

                                          \varpi


$$\varpi$$

TeX has a question on the 'var' prefix, and Wikibooks has something relevant.

The various forms of pi are present in Unicode as:

• U+03A0 Π greek capital letter pi (HTML Π · Π)
• U+03C0 π greek small letter pi (HTML π · π)
• U+03D6 ϖ greek pi symbol (HTML ϖ · ϖ)
• U+220F ∏ n-ary product (HTML ∏ · ∏)
• U+1D28 ᴨ greek letter small capital pi (HTML ᴨ)
• U+1D70B 𝜋 mathematical italic small pi (HTML 𝜋)
• U+1D6D1 𝛑 mathematical bold small pi (HTML 𝛑).

It is used to denote the longitude of the periapsis, as in your case.