Dasha is not: staving off disease or afflictions caused by supernatural beings (dasha).
Dasha means "time."
Dear Professor Toffin: I read your article on astrology and timing-very interesting and thank you for addressing what I feel is a cultural topic of great interest but which so far has been neglected in public discourse.
I don't have time to address all the points raised in your article, except these few important points:
Dasha means "time"--specifically the time ruled by each planet in a person's life at that specific time. Maha dasha, antar dasha, pratyantar dasha, shoookshma dasha and prana dasha--you can go down to the breath level, and all of these are planetary forces ruling a person at a specific time. More here on how to calculate:
This calculator does a basic vimosottari dasha cycle: http://www.astroaura.net/dasa-bhukti-periods.html
The Nepalis do a 80 year cycle, not the 120 vimosottari dasha cycle.
More here on dashas from Wikipedia, my favorite source of unbiased information.
And I don't know Mangal Raj Joshi, but Radhanath Lohani, astrologer of King Mahendra, had specifically advised the king not to get his sons married to women who were sisters and related to each other. This he thought brought great misfortune. You can't really blame the astrologers after the fact (re: royal massacre) if the kings don't listen to the astrologers' advice!
Take care and enjoy the read, sushma