some Tibetan unicode symbols are so obscure it's hard or even impossible to find information about them. the very first Tibetan unicode proposals unfortunately do not exist on the internet.
this and my Wiktionary page are my attempt at explaining these symbols. take the IPA transcriptions with a grain of salt!
Astrological signs (U+0F15 - U+0F19)
not astrological signs in the traditional sense. these are callendrical symbols used in Tibetan astrology.
༕
(U+0F15) TIBETAN LOGOTYPE SIGN CHAD RTAGS
when i first saw this symbol, i thought it was a face... but it's actually a stylized ligature of ཆད (chad /t͡ɕʰɛː˥˨/). you see ཆད on Tibetan and Bhutanese lunar calendars to mark skipped days. ཆ and ད are often written on top of each other, like ཆྡ.
༖
(U+0F16) TIBETAN LOGOTYPE SIGN LHAG RTAGS
a coordinate symbol to CHAD RTAGS, a stylized ligature of ལྷག (lhag /ɬa(k̚)ˀ˥˥/). it marks doubled days on callendars, and like chad, it is written as ལྷྒ.
༗
(U+0F17) TIBETAN ASTROLOGICAL SIGN SGRA GCAN -CHAR RTAGS
the symbol of the shadow planet Rāhu, known as སྒྲ་གཅན (sgra gcan /ʈ͡ʂam˩˨ t͡ɕɛ̃˩˨/) in Tibetan.
༘
(U+0F18) TIBETAN ASTROLOGICAL SIGN -KHYUD PA
this symbol has stumped me for months. i assume it means འཁྱུད་པ, which, in the context of skar rtsis means present or current date, however i’ve been unable to find it being used anywhere. i’ve gone through old astrological and astronomical documents and haven’t found it. *sigh*
༙
(U+0F19) TIBETAN ASTROLOGICAL SIGN SDONG TSHUGS
i haven’t seen this one be used either, but it’s supposedly a small shad inserted under numbers in astrological contexts, according to Tibetan! 5 for Word.