Verformung der Sonne am Horizont

The low-standing sun, or more rarely the low-standing moon, often shows strange deformations. Even planets like Jupiter or Venus are sometimes linearly distorted during rise and set. The cause is nothing other than a mirage, caused by two or more air layers of different densities, where the light beam from the sun is "bent" at the interface of these two layers. Two cases are distinguished here:

• When the lower air layer is warmer than the upper one (e.g., in a ground inversion), the sun's mirror image initially appears outside the mirroring strip and later merges with the sun. Eventually, the sun and its mirror image disappear behind the line of sight.
• When the air at the ground is colder (e.g., over water and ice surfaces), the line of sight is bent so that one can see below the horizon. Thus, the sun and moon can still be visible when they are astronomically already below the horizon. Characteristic for this case is the so-called blind stripe, as no rays reach the observer in this angle range.