Bear the Constellation was not photographed in the Northern Hemisphere. I do need somebody to name the Constellation which will then allow me to post the relevant clue. I'm hoping some of our night owls who live south of The Equator will be able to name it..... Incidentally I'm sure the pilot in the next image would be very familiar with both the Constellation and the Bay of Bengal. (Oh yes and the airfield too.) I believe the waters immediately around the Andaman and Nicobar Islands are Quite Warm but are beyond swimming distance to that part of The Empire we are trying to discover. Nevertheless a good call.
Dated 1925.
I'm putting myself and the dog out now. More tomorrow with luck.