Admiring the rainbow we sometimes notice that it has a twin – another arc, modest, slightly prominent. And some have seen just three or four rainbows at the same time. But such cases are very rare. Double Rainbow consists of a bottom – brighter, and above, less bright, for a short period. The first is called primary, the second – sideline. Both rainbows face each other with red edges of the arc so that the main rainbow red edge was on the convex side. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops, and appear at an angle of 50–53°. As a result of the second reflection, the colors of a secondary rainbow are inverted compared to the primary bow, with blue on the outside and red on the inside. The secondary rainbow is fainter than the primary because more light escapes from two reflections compared to one and because the rainbow itself is spread over a greater area of the sky. The dark area of unlit sky lying between the primary and secondary bows is called Alexander’s band, after Alexander of Aphrodisias who first described it.
In addition to the primary and secondary rainbows which can be seen in a direction opposite to the sun, it is also possible (but very rare) to see two faint rainbows in the direction of the sun. These are the tertiary and Quaternary rainbows, formed by light that has reflected three or four times within the rain drops, at about 40° from the sun (for tertiary rainbows) and 45° (Quaternary). It is difficult to see these types of rainbows with the naked eye because of the sun’s glare, but they have been photographed; definitive observations of these phenomena were not published until 2011.
From ancient times to the present time, people enthusiastically refer to the phenomenon as a rainbow. Older generations have interpreted that a rainbow acts as a bridge across the sky and to see it after the rain is a very good sign. It is a harbinger of good, good events and news.
To see a double rainbow brings great joy. A good sign, to see a rainbow for a woman who has daughters. Especially positive is to see double rainbow in summer and rare in winter or around the sun. Twofold sign is to see the phenomenon at night.
Folk omens clarify that to see a double rainbow in the sky – a great rarity. This sign portends you a positive life changes. You will find success in business, career growth and good news. Such action can be seen at any time of the year: winter, spring, summer and autumn.
To see a rainbow in the winter means a good sign, good luck will accompany everything you planned to do, even if you yourself do not believe it. To see a rainbow in the fall, you do not need to wait long, as at this time of year it is a very common phenomenon.
Folk omens say that two rainbows around the sun in ancient times was a bad action, as it means the transition of the dead to the living world, for them such a phenomenon around the sun acted like a bridge.
To see a rainbow Slavs went to the lake, pond, as they believed that one end of a rainbow is down into the water and so it is gaining strength. Anyone who saw it knew that it quickly disappears and you need to have time to make a wish. For them, the phenomenon had healing power, as well as water. Also, there was a belief that one end can suck a man and his soul, so walking in the rainbow was forbidden. Particularly negative attitude to the rainbow of the night, as people believed it was a way to dark, evil spirits come down to earth.
It was the rainbow gave thee birth, and left thee all her lovely hues. W. H. Davies