Saturday, December 19, 2009

Moonbow


Moonbow and Venus imaged by Rob Ratkowski (photography) in May 2004. Moonbows are very rare. The moon must be bright and not too high, the sky must be dark else the faint bow will not be visible and there must be rain in the direction opposite the moon. Orion was setting when Rob took this spectacular image, Venus is the bright object inside the bow. Mars is above it to the left and Saturn is above Mars and outside the primary. Capella is the bright star to the right (north) of Venus. Do not expect to see much colour with the unaided eye because moonbows are usually too faint to excite the colour sensors in our eyes. We therefore mostly see them as a series of grey shades.

2 comments:

Richard said...

Moonbows are, indeed, very rare. I grew up on the water and worked professionally on boats for close to 30 years and have only seen ONE.

It was in November '91. It was on the midwatch in the middle of the Atlantic while making a delivery of a sailboat from Spain to Florida. As you said, the conditions have to be JUST right for one to form. It was a perfect arc from horizon to horizon ahead of the boat and surprisingly bright. It's such a rare thing that I went below and woke the rest of the crew so they could witness this extraordinary sight, too.

Anonymous said...

Very Interesting!
Thank You!