Re: [guide-user] Visual limit value in Quick Info - how is it calculated?

Bill J Gray Oct 23 11:53 AM

Hi André,

Hmmm... as far as I know, Guide's method for computing this is
almost exactly the same as in Brad Schaefer's article. (I made a
small alteration to allow the moon to contribute some light when it's
partly below the horizon.) The source code is available at

Look in 'vislimit.cpp'. (This can be compiled as C or C++ code.)
This code is used for the limiting visual magnitudes shown in Quick
Info, and also for computing the realistic sky shading shown when
you use Display... Background... Realistic.

It's a little puzzling to me that Guide and Schaefer's code would

-- Bill