> for any test I have place year 0 into time menu and Giude
> accepted this input.
>
> But I know that year 0 don't exist.
>
> Is this a bug?

No, it's a feature. Guide uses astronomical years, not chronological
years. The relation between the two of them appears below:

Astronomical Chronological
year year

+5 5 AD
+4 4 AD
+3 3 AD
+2 2 AD
+1 1 AD
0 1 BC
-1 2 BC
-2 3 BC
-3 4 BC
-4 5 BC

In the chronological year numbering scheme, year 0 is missing,
but in the astronomical year numbering scheme there *is* a year 0

Chronological years were invented around 500 AD, when people
sitll used Roman Numerals, which lack a symbol for zero.
Astronomical years were invented by Cassini in the 1700's,
when we had switched to the current number system, where there
is a symbol for zero.

----------------------------------------------------------------
Paul Schlyter, Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40, S-114 38 Stockholm, SWEDEN
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