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Moonbow Challenge: Bows by Stephen O'Meara at Mauna Loa, Hawaii. ©Stephen O'Meara, shown with permission.

The moonbow challenge is to image a rain-generated bow closest to the New Moon.

The upper image was taken when the waxing crescent was only 4 days 6 hours after new.

The faintly coloured bow crosses Perseus and shows Comet Holmes. The sky was quite dark at the beginning of nautical twilight (sun 12 below the horizon).

Moonbows are rare. They ideally need a bright moon less than ~35 high, a dark sky and a rain shower opposite.

To get these conditions a low latitude helps, as does a season when the ecliptic (the annual path of the sun across the stars) is strongly tilted upwards relative to the horizon. The moon's position above or below the ecliptic also counts. As for the weather, we need frequent showers interspersed with clear skies. Weatherwise, Hawaii, the Scottish Highlands and Isles and Northern Ireland are favoured places for lunar and solar rainbows.

The previous record was 7days 14 hours. Now we have 4 days 6 hours! Any challengers?


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