Galilei, Galileo Dialogues on two world systems 1661, tr. Salusbury, Thomas

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275
us see whether by withdrawing it 20. minutes onely, it will rise
to the height of 32. semidiameters: See the short and true opera­
tion. Multiply the sine of the angle B D C, by the sine of the



chord B D, and divide the product, the five last figures being cut
off by the sine of the Parallax, and the quotient will be 28. se­
midiameters, and an half, so that though you make a correction
of 4 gr. 22 min. 30 sec. taken from 4 gr. 42 min. 30 sec. it shall
not elevate the star to the altitude of 32. semidiameters, which
correction for Simplicius his understanding it, is of 262. minutes,
and an half.

In the second operation made upon the observations of Hain­
zelius, and Sculerus, with the Parallax of 0 gr. 8 min. 30 sec.
the star is found in the height of 25. semidiameters or therea­
bouts, as may be seen in the subsequent working.