The Sun and the Moon are much too small in Celestia. Whats wrong?
Their diameters are exactly right. As seen from the earth, they are both about a half-degree across. Celestia’s window is 45 degrees across, so the Sun and Moon are about 1% of that. They are drawn only 10 pixels wide if your screen is 1024×768. The apparent size of the Sun and Moon as we see them in the sky is a psychological illusion. There are several different explanations for this. If you take a picture of the moon with a camera lens that has the same field of view as Celestia, you may be surprised at the small size of its image. But if your head is positioned e.g. 70 cm away from your e.g. 17″ monitor, which measures 32 cm across (at least mine does), then the effective field of view looking at the Celestia sky “through” your monitor screen is 2*arctan((32/2)/70)) ~ 26 . Hence, if you decrease the Celestia field-of-view to 26 you may get a more accurate appearence of what you would see looking out the window.
