Maths/Sanskrit help needed

[Martin Gansten]

I sincerely request the help of anyone out there who specializes in one or
more of the following:
        1. Indian mathematics;
        2. Indian astronomy;
        3. Corrupt/hybrid forms of Sanskrit.
In an 18th century (?) South Indian astrological MS, I have come across the
following passage:

zakaabdaapi gate jyotir viraame vopadezata.h
svadezakaalabhedena padmaadricandraagniyutaa.h zakaabdaa.h kalivatsaraa.h
kalyaabdaarkagato maasayutaas trikhaadrize.sata.h
labdhayutaasturayutaa.m samaasair api sa.myuta.h *
kha.m vazvaaghno dinayuta.h dvizazevaagnibhaas tribhi.h
lalabdhek.sa (-) nair hiina.m zukravaaraadika.m dinam
dyuga.na.m ga.nanair hitvaa bhaajayed api bhaajakai.h
labdha.m raazihata.m ze.sa.m khaagnibhir bhaajanair v.rtaa
bhaagaze.sa.m khatarkaghna.m h.rtahaaraikadaa puna.h
vikalaaz ca bhavanty evam aya.m syaan madhyakhecara.h
gu.nakaaro raver bhaa.na ziirendur haaraka sm.rta.h
zarendu tarka.sa.dbhaago khakhaarbhaagnirvidhogu.na.h
zaradarkanidhiz candra vasavo haaraka sm.rta.h

* (another, but usually less correct, transcript of the same text reads:
lubdayuktaas tu rahitaa.m samaasair api sa.myuta.h)

I am able to discern only fragments of meaning in this: the second line
obviously deals with the difference between the Saka and Kali eras, and
later there is mention of weekdays, and of the mean motion of a planet (?
madhyakhecara); also some basic mathematical terms (like words for
multiplication and division) and words signifying numbers according to the
ar.navaadi system -- but the overall meaning of the passage utterly escapes
me. I would greatly appreciate any help from scholars with experience of
this sort of texts -- or just from better Sanskritists than myself!

Regards,
Martin Gansten