astronomical calendar

21 LETTERS · STARTS WITH A

astronomical calendar is a valid 21-letter word worth 27 points in Scrabble and 34 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

A1S1T1R1O1N1O1M3I1C3A1L1C3A1L1E1N1D2A1R1

1 + 1 + 1 + 1 + 1 + 1 + 1 + 3 + 1 + 3 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 1 + 2 + 1 + 1 =27 PTS

DOUBLE WORD → 54TRIPLE WORD → 81

MEANING

What does astronomical calendar mean?