Name	Last modified	Size	Description
	Parent Directory		-
	space_angle.png	2006-01-04 11:03	11K
	space_angle.gnp	2006-01-04 11:00	1.5K
	space_ang30.gnp	2006-01-04 11:00	1.5K
	space_ang15.gnp	2006-11-27 18:49	1.5K
	space_an_dg2.png	2006-01-04 11:03	11K
	space_an_dg.png	2006-01-04 11:03	11K
	space_a30dg2.png	2006-01-04 11:03	10K
	space_a30dg.png	2006-01-04 11:03	10K
	space_a30.png	2006-01-04 11:03	10K
	space_a15dg2.png	2006-11-27 18:49	9.9K
	space_a15dg.png	2006-11-27 18:49	9.5K
	space_a15.png	2006-11-27 18:49	9.9K
	illuminanceP.gnp	2014-06-25 19:07	1.6K
	illuminance.png	2012-06-18 22:48	7.9K
	illuminance.pdf	2012-11-27 19:58	11K
	illuminance.gnp	2013-05-06 13:30	1.5K
	illumin_cz.pdf	2013-02-08 11:15	8.1K
	illumin_cz.gnp	2014-07-04 18:59	1.2K

It is amazing, how well a planar approximation of pi*r^2 works... The graphs going just to 30 degrees radius show, that up to 15 degrees, even cosine correction (giving illuminance of a plane) is completely negligible.

*.gnp are programs which have produced the resulting *.png by a command like
gnuplot space_angle.gnp
– it's easy to adapt them to produce scalable PostScript output instead.

(made by Jan Hollan, subject to GNU public license)