SR-71: Rock Switching Hands

[rjemery]

In "The Black Watch: The Men Who Fly America's Secret Spy Planes", Ernest Gann writes (p 18):


"Away with the old sextant and chronometer; the same stars that once guided the ancients now tell the Reconnaissance Systems Operators [SR-71 backseaters] to put the rock in his other hand. North is that way."


What is meant by "put the rock in his other hand"?

[oxford blue]

It's not very clear, but since he's talking about "the ancients", I think he's referring to the lodestone. Prior to the invention of the modern needle-type compass, the lodestone was a lump of magnetised rock which indicated the direction of Magnetic North. The ancients would also have used the stars and a sextant (or more likely a quadrant or an astrolabe at that time).

The SR-71 has an astro-tracker. A photo-electric cell can be locked onto a star and can even continue to track it in quite broad daylight. It's not particularly good at giving a position, but it is a very accurate source of heading - and therefore replaces the compass.

I think that that is what Gann was trying to say - but I agree that his prose is a bit purple in this particular passage. He must have been getting old by the time he wrote this. In general, he's one of the best of aviation writers.