Monday, Jul 29, 2024

Definition of green ray (World Meteorological Organization): A predominantly green coloration of short duration, often in the form of a flash, seen at the extreme upper edge of the Sun, Moon or sometimes even a planet when disappearing below or appearing above the horizon . The Legend of the Green Ray “... If there is green in Heaven, it is certainly that green, the true color of Hope”. This is how the French writer Jules Verne describes the green ray in the sentimental novel Le Rayon Vert of 1882. The writer continues: “... a green ray, but of a marvelous green, of a green that no painter can obtain on his palette, a green of which nature neither the variety of plants, nor the color of the clearest sea, have you ever brought back the nuance!...” Many believe it is a legendary phenomenon, but it is real, and not even that difficult to observe. If we were in the habit of pausing for a moment in contemplation, while the Sun sets or rises, in the few minutes in which we can admire our star without protecting ourselves from excessive light, perhaps we would notice it without going to exotic countries where it is believed to be more visible. The green ray is undoubtedly one of the atmospheric phenomena that most strikes the imagination and imagination of man. It consists in the vision of a faint green streak, which forms on the top of the solar disk when setting or rising; in particular conditions, it can transform into a real green flash, or fade into blue/indigo and therefore transform into a blue ray, but Veronese green is the most common shade. The color is called "Veronese green" in honor of Paolo Veronese, the painter who discovered the pigment. This extraordinary event belongs to the photometeor family and can manifest itself in two different ways. In the first case, when the solar disk is very flattened and clearly visible above the horizon, a very thin green arc can form for many seconds which detaches itself from the upper edge of the Sun, fraying into one or more overlapping green filaments (green rim ). If this passes through a thermal inversion layer, then it lights up in a real green flash. In scientific literature when the Sun undergoes all of these deformations, it is said that we are in the presence of a mock mirage. The second case is the most famous: when the Sun is almost completely below the horizon line, the almost instantaneous formation of the green rim can be observed without the pre-formation of the green arc. Subsequently the green streaks unite creating a single green ray (green flash). During its extinction you can also perceive a faint green flash coming from below the horizon (right where the Sun has set) which illuminates the sky for a few degrees upwards, as if it were a lighthouse (green ray). The latter is Verne's true green ray. The duration of the event, from medium Italian latitudes, can vary from a fraction of a second for the green ray, up to about 2 seconds for the green flash; this mainly depends on the latitude of the observation site and the speed of sunset during the year. For example, in 1929, on his return from the Arctic camp of Little America (lat. 78°S), Admiral Byrd reported having observed a ray with an extraordinary duration of 35 minutes. And again, during the spring solstice of 2000, researcher R. Marks managed to photograph an extraordinary blue ray from the South Pole 48 hours after the Sun had begun to set. Nikon Z9 at 320Iso, Nikon Z400 /4.5 S + Nikon Z 2X, f/20, Exposure of 1/50, Site: Marina di Pisa, Pisa, Tuscany, Italy