[LEAPSECS] Bulletin C and all that

[Rob Seaman]

On Jan 26, 2015, at 12:21 PM, Warner Losh <imp at bsdimp.com> wrote:

> It all depends on the data that you are using whether the new day starts at midnight
> or noon. If you are talking to astronomers before the 20th century, chances are good
> it is noon.

Big fan of Patrick O'Brian.  Frequent mention is made in his Nelson-era novels of their taking noon sightings of the Sun and declaring the start of a new day.  I don't recall any discussion of mean versus apparent time, however, though the ships' chronometers are often referred to.

> Civil folks chances are it is midnight. This ambiguity is why insurance companies
> say that something runs from 12:01am or 11:59pm or some other time that’s unambiguous.

Of course ante and post meridiem also reference the Sun.  Perhaps make that "currently unambiguous" ;-)

Rob