How to interpret this old degree notation? I'm trying to follow the calculations in this paper on page 5 (see image below). The paper is describing traditional methods of calculation for a luni-solar calendar.

The math is not hard, but I can't make sense of the notation.

I figured that the ... = 150 : 1780 (as in step 3) means that 150 is the integer result, and 1780 is the remainder.

But what is ... = 2; 19:28 (step 8)? Degree; minute:second? Okay, but then I'm lost at step 10 with 134 * sin(0:32) = 0:01. I haven't managed to get that result.
This doesn't really answer your question, but I read https://github.com/profound-labs/calculating-the-uposatha-moondays/blob/master/references/Rules%20For%20Interpolation%20in%20the%20Thai%20Calendar.pdf and noted that footnote 13 (which is referenced by equation 8, although it sort of looks like 3^13) reads:


The routine subtraction of 3 arcmins is a causing Ashadha to be month 
10; but by this Wat geographical longitude correction for the sun, as 
is the Tapotharam reckoning Vaisakha is month 7 (Keng subtraction of 
40 arcmins for the moon (sec. C13). Tung style), causing Ashadha to be 
month 9. 


which suggests the calculation is being done in arcminutes, not degrees.

Unfortunately, this doesn't help, since the result is 76.5283 arcminutes, which is nowhere near 2 degrees 19 minutes 28 seconds (which is 139.467 arcminutes).

134*sin(0:32) may refer to 32 seconds of arc, and the result is 0.02 which is 1 minute or arc (0:01). Terrible use of notation here if that actually is the case.