The Moonset Time of the March Full Moon From Washington, DC

i doubt ingo would have checked when moonset was in washington for the march full moon in 19 75. Even if he had tried to check, that task would have been much harder in 19 98 because internet was still so new. Hypothetically it could be something ingo added later, after he'd forgotten precisely what had happened. But more plausibly, it would be something that he wrote soon after he got back to new york. There would still be other ways of explaining what he remembered axlerod telling him, including the fuzziness of his own memories.