From what I read, your script JULIAN could be appropriately named Dayofyear.
The other scripts I believe use the ASK/MANMAN julian algorithm which is
based on Jan 1 1972 (?)

If a new HP var, HPDAYOFYEAR, is provided, then the leapyear checking could
be avoided.
But the julian day algorithm may not be widely (globally) accepted.

If a julian algorithm is adopted, these R/W HP vars could be useful then.
        HPJULIAN                int
        HPJULIANYEAR            int
        HPJULIANMONTH   int
        HPJULIANDAY             int
With the feature that when any of these are written to (ie: SETVAR
HPJUL....), all the others are adjusted.
I could set HPJULIANYEAR, MONTH, DAY, then do calculations with HPJULIAN,
and then read the final result
from HPJULIANYEAR, MONTH, DAY.

Just a thought.
+=====================================
 Keven Miller   KC7LYD
 [log in to unmask]   (Salt Lake City, Utah, USA)
+=====================================