Hi Hans-Goran,


The human eye is able to adapt to very different brightnesses as Venus
(mag -4) and weak stars (mag 6); that represents a difference of 10 mag,
that is to say a brightness ratio of 10,000. A computer's display is only
able to give 256 levels of brightness. So it is impossible to render the
stars' brightnesses in a so-called "realistic way".

As a consequence, some "conventions" have to be accepted, e.g. the
diameters of the stars are linked to the magnitude.

In the case of the Sun and the Moon, such a convention is unapplicable,
because these bodies have apparent diameters. For these, the diameter of
the disk is linked to their actual angular diameter.


Laurent Zimmermann
http://users.skynet.be/zmn/cab

----- Original Message -----
From: H.G.Lindberg <gorlin@...>
To: <guide-user@yahoogroups.com>
Sent: Monday, September 10, 2001 6:18 PM
Subject: [guide-user] size


> The size of star dots and levels in Guide ,driving me crazy......
> How get automatick size of star dots versus magnitude in a realistic
> way????
> (Vega is bigger then our sun! :o))
> Regards
> Hans-Goran
>
>
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