|Solar Longitude on the Zodiac||from||to, not including[a]||Lunar longitude correction|
|middle of Pisces-middle of Taurus[b]||315°||15°||0°|
|middle of Taurus-beginning of Gemini||15°||30°||0°15′|
|beginning of Gemini-beginning of Leo||30°||90°||0°15′|
|beginning of Leo-middle of Virgo||90°||135°||0°15′|
|middle of Virgo-middle of Libra||135°||165°||0°|
|middle of Libra-beginning of Sagittarius||165°||210°||-0°15′|
|beginning of Sagittarius-beginning of Aquarius||210°||270°||-0°30′|
|beginning of Aquarius-middle of Pisces||270°||315°||-0°15′|
[a] My understanding of the word usage in the original.
[b] See Chapter 11, Law 7 on the start of Jewish Zodiac. (TODO reference)
The value of mean [lunar longitude] after you add to it or subtract from it or leave it as it is - that is mean lunar longitude approximately a third of an hour after sunset on the date you are calculating it for. And this is what is called mean lunar longitude at observation time.