Moonlight off Dungeness
Wikipedia's "On this day" for 3 October includes the Battle of the Narrow Seas (1602). Its article says the fight began "in the moonlight of 3 October, just before midnight", when Robert Mansell's ships caught Federico Spinola's six galleys off Dungeness. In 1602, though, England still counted dates by the Julian calendar, while Spain and the Dutch used the Gregorian, ten days ahead. So which 3 October was it? The Moon can tell you.
The Moon is placed with a standard low-precision formula: longitude and latitude from the six largest periodic terms, then converted to altitude for Dungeness, 50.9°N 1.0°E. On NASA's own times for 1602 it gives elongations of 180.1° at full moon (1 October, 06:07 UT) and 359.9° at new moon (15 October, 05:48), so its positions here are good to about a degree. The horizon is flat sea, and twilight is left out.
What it shows
| Reading of "3 October 1602" | At 23:00 | |
|---|---|---|
| Gregorian (Spanish and Dutch reckoning) | Moon two and a half days past full, 92% lit, 43° up; it rose about 18:10 | moonlight |
| Julian (English reckoning) = 13 October Gregorian | Moon two days before new, 2% lit, 44° below the horizon; it rose about 05:25 next morning | dark |
So the article's "moonlight of 3 October" works only if that date is Gregorian. The article doesn't say which calendar it uses, and I haven't read its sources (Wernham, Graham, Motley, Archibald). If those English accounts count Julian dates, the battle's evening may in fact have been 23 September in English reckoning.
The same article names Mansell's ships two ways. First he leaves with "the 30-gun Hope along with the 42-gun Victory and Answer". A paragraph later, "Moon, Samson and Answer charged at the Spanish ships".
What stands on what
| Item | Source |
|---|---|
| The battle, the quotations, the ships | Wikipedia, Battle of the Narrow Seas; the day's Selected anniversaries |
| Full and new moon of October 1602 | Fred Espenak, NASA, "Phases of the Moon: 1601 to 1700", Gregorian dates after 1582 |
| England on the Julian calendar until 1752 | Wikipedia, Calendar (New Style) Act 1750: 2 September 1752 was followed by 14 September |
| Moon position, altitudes, moonrise | My calculation, in the page's script, checked against NASA's phase times |