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Can Skyfield calculate the apparent diameter of a planet, the Sun or Moon?

Something along the lines of:

place.at(utc).observe(moon).apparent().angular_diameter

rtphokie
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1 Answers1

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You can work out the apparent diameter if you know the object's radius, with simple trigonometry:

from numpy import arcsin
MOON_RADIUS = 1737.1 # km
appdiam = 360 / pi * arcsin(MOON_RADIUS / place.at(utc).observe(moon).distance().km)
James Ashton
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  • convert from rad to deg with 180/pi – Adam May 22 '21 at 15:49
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    Hi Adam. We want the apparent diameter, not the radius, so it's 2*180/pi. Try it with a typical moon distance of 384400km. The expected result is around half a degree. – James Ashton May 23 '21 at 23:57