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   Rainbow Orders 

 
Rainbows all over the sky - High order rainbows do not occur in any orderly sequence. They lie both sunward and opposite the sun (see an all-sky simulation).

The one and two internal reflections of the primary and secondary bows send light back towards the sun and hence their bows appear opposite the sun and centered on the antisolar point.

Three and four reflections send light forwards to give bows that circle the sun. 5th and 6th order bow rays are backward scattered and they occur opposite the sun like their primary and secondary counterparts.

Each internal reflection weakens the rays and the higher order bows are progressively fainter. Look also at how the entrance ray that makes each bow grazes closer and closer to the edge of the drop. This makes the higher order bow colours spread wider and reduces their brightness even further.







   Rays of the first six rainbow orders

Each extra reflection inside the raindrops produces a different rainbow.

The higher order bows get progressively fainter because each reflection dims the rays. They also get broader and hence their surface brightness is even further reduced.

Only those from one and two reflections and the zero order glow have ever been reliably sighted in the sky.

Click the drops to see the rainbows.