NavList:

David Pike, you wrote:
"Giving up the temptation to check if there was ever a USS Venus (there was but not until 1943), I googled USS Jupiter and bingo.  She was a USN Fleet Collier converted in 1920 to become the USN’s first aircraft carrier.  She was renamed at the same time USS Langley after the US aviation pioneer and astronomer.  She was later converted to a seaplane tender, and it was while in this guise that on 9th December 1941 she fired off 300 rounds at the planet Venus mistaking it for a flash of sunlight reflected from a Japanese aircraft.  She was scuttled on 27Feb 1942 following an air attack."

That's great! Thanks for filling in those details. :) Yes, indeed. USS Langley, converted from USS Jupiter, was the US Navy's first aircraft carrier: CV-1 (see PS). No longer CV-1, it had been downgraded five years before Pearl Harbor, and in any case it wasn't much of a warship.  It was in Manila at the time of the attack on Hawaii. Almost simultaneously Japanese forces began their assault on the Philippines (that would be December 8 local date). Many USN ships left Manila for points south as quickly as possible. Naturally they were on "highest alert" and ready --and surely "eager"-- to shoot at any Japanese aircraft.

As I have said many times in recent years in NavList messages, Venus is shockingly bright in the daytime sky when the geometry is right (for about six weeks, ending two weeks before inferior conjunction, and another six weeks starting a couple of weeks after inf. conj.), and this was one of those days. Once spotted, Venus could easily have been mistaken for an enemy aircraft.

The almanac data I provided did not explicitly indicate that Venus was near "maximum brilliancy", but there is an implicit clue. The parallax of Venus (PA in the "Altitude Corrections" columns) is double the Sun's parallax so roughly half the distance to the Sun (for comparable altitudes since the parallax correction is inversely proportional the distance and directly proportional to cos of the angular altitude), and that's just about right for maximum brightness. Also, checking with "Stellarium" we can see that the apparent magnitude of Venus was -4.7 on Dec. 9 (very bright and easy to see in daylight) headed for a peak brightness, only slightly brighter, of -4.9 about three weeks later. This was Venus "prime time".

I came upon this story while working on a map. I'm trying to create some mapping images that display the Pacific and Indian Oceans "properly" from the point of view of long-distance navigation. Large sections of the oceans, hundreds of miles on a side, are "full of atolls", like the Marshall Islands and the Tuamotu Archipelago in the Pacific, as well as the Maldives in the Indian Ocean. On most maps, the ocean looks empty, but these atoll swamps are nearly impassable. So I've been digging around, looking up various island histories as I go, and inevitably this leads to Pacific battles and sunk warships, especially from 1941 to 1945. Reading about USS Langley on Wikipedia, I came across the story of shooting at Venus, and my immediate reaction was to test it. First, I looked at the (apparently) original source for the story. It was an "oral history", primary source history, but subject to the entropy of memory. Did the story fit the facts? Would the date in the story match a time when Venus could be confused with an aircraft? And yes, the timing was almost ideal. 

Frank Reed

PS: Why "Langley"? Samuel P. Langley was once celebrated as the inventor of the first airplane. The Wright brothers were ignored for decades. If the carrier conversion of "USS Jupiter" had happened later, that first aircraft carrier might have been named "USS Wright Brothers". But even after the former USS Langley was sunk a few months after Pearl Harbor, the controversy had not been resolved.