136
You're absolutely right, Johannes! I was in a bit of a hurry when chasing up that reference yesterday, but looking at it more closely now, I see that Abū Maʿshar talks of 'half the body of the planet of fewer degrees'. So if the conjunction is between Saturn and the Moon, then it would be weaker after the Moon has separated from Saturn by 9°. So this is not the 'average' mentioned by al-Bīrūnī, if indeed 'average' is correctly translated in the first place (Arabic is not one of my languages, unfortunately).
https://astrology.martingansten.com/

137
The divergent use of "half orbs" with different authors can indeed be confusing. I must confess that I was in a bit of a hurry myself and intended to dedicate myself to the entirety of Abū Maʿshar's text on application and separation later.

Thank you for the clarification, Johannes.

Of course, that leaves us with the question if any of the other sources mentioned by Martin might be relevant in this regard or if we have to content ourselves with al-Bīrūnī's respective remark as the earliest tangible reference to moiety orbs.
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