This atmospheric phenomenon is called The Belt of Venus.This off-coloured band between the dark eclipsed sky and the blue sky can be seen in nearly every direction including that opposite the sun.Straight above,blue sky is normal sunlight reflecting off the atmosphere.In the belt of Venus,however,the atmosphere reflects light from the setting(or rising)sun which appears more red.The belt of Venus can be seen from any location with a clear horizon.Basically,it is a pink to brownish border separating the dark shadow band of the Earth from the sky above it.I lucked out by getting anti-crepuscular rays in the same shot.