[zwiasrdt] appearance of earth from geosynchronous

earth radius = 6378 km

geostationary orbit altitude above surface = 35786 km

halfangle = asin(earthradius/(earthradius+altitude))

angular diameter = 2 * halfangle = 0.30370 radian = 17.4007 degree

solidangle = 2 * pi * (1-cos halfangle) = 0.072300 steradian

proportion of sphere = solidangle / (4*pi) = 0.00575349

how bright is the earth?  according to wikipedia, if fully lit up by the sun and viewing with the sun behind you (i.e., opposition), earth's apparent magnitude viewed from 1 AU away would be -3.99, using some sort of average earth albedo.  earth's albedo varies by a factor of 6 depending on cloud cover.  converting from astronomical magnitude at 1 AU to lumens at geosynchronous requires a little bit more work.

motivation is to simulate being in space, to simulate the appearance of earth from space by viewing a luminous image in a dark room.  can it be done?  or does the earth reflect colors that the eye can see but cannot be replicated by display technologies?

getting the eyes to focus on "infinity" (35786 km) probably requires a virtual reality headset.  with a VR headset, we could be closer than geosynchronous.

the other alternative is to look at a large display from far away.  how large and how far is close enough to infinity?