WP 34S conversion error

[walter b]

(10-10-2014 07:04 PM)Dieter Wrote:  

(10-10-2014 08:23 AM)walter b Wrote:  Footnote 18 on that NIST site reads: "This conversion factor is based on 1 d = 86 400 s; and 1 Julian century = 36 525 d.

Which is correct for a Julian century.

As written.

(10-10-2014 07:04 PM)Dieter Wrote:  

(10-10-2014 08:23 AM)walter b Wrote:  (This definition is not consistent with the length of a year being 365.2425 days.

Which is correct for an average Gregorian year.

Quote:But there are even more definitions of a year...)

You bet. So the question is: which definition of a year is valid for a light year? A tropical year maybe? This varies permanently so that anything more precise than 365,242... days/year would not make much sense.

I think that's the reason the light year was defined based on an average year per convention. And it's just a yardstick for measuring distances in the universe, so who cares about deviations less than 10^(-4)? Has anybody an idea, however, why they took the Julian instead of the Gregorian year? The latter would have been more consistent IMHO but I'm no astronomer.

d:-)