# What is ephem's body size attribute equivalent in Skyfield?

I am porting some code that uses PyEphem to using Skyfield. Somewhere along the code I use the body's size attribute:

obs              = ephem.Observer()

obs.date         = ephem.date(time)
moon             = ephem.Moon()


I have looked in Skyfield documentation but couldn't find the equivalent to the body size attribute. Does anyone have an idea if there is an equivalent in Skyfield?

• Please edit your question, it seems cut-off. – user10509 Nov 15 '19 at 15:46
• This question seems clear enough to me. I've added a little formatting and dropped the "thank you in advance". – uhoh Nov 16 '19 at 0:53

As far as I know, Skyfield itself doesn't contain any tabulated data on astronomical bodies itself. Instead, it allows you to draw data from other sources.

• for motion, you select a NASA JPL ephemeris yourself and Skyfield downloads and interpolates the positions and velocities
• for Earth artificial satellite motion Skyfield downloads TLEs or lets you type them in and uses the standard SGP4 algorithm to propagate them
• for the 3D positions of Topos relative to Earth's center of mass Skyfield uses the standard WGS84 model, or what some people call "GPS coordinates".