Enjoy today’s Cryptogram and have a Merry Christmas.

P BSGGBW LNSBT,Solution to previous Puzzle: (select the yellow text with your cursor to read):
P FNSZSZQ FGPY,
P FGPDBW YVTW,
GNW TKKY PXPY.IWG SZ GNPG CBPLW,
FK LYVTW, HKYBKYZ,
GNW NKCW KH PBB
GNW UKYBT UPF DKYZ.— PZKZ
A LITTLE CHILD,
A SHINING STAR,
A STABLE RUDE,
THE DOOR AJAR.YET IN THAT PLACE,
SO CRUDE, FORLORN,
THE HOPE OF ALL
THE WORLD WAS BORN.— ANON
HAL'S CRYPTOGRAM HELPER
=MOD(ATAN2(COS(B2)*SIN(B3)-SIN(B2)*COS(B3)*COS(C3-C2), SIN(C3-C2)*COS(B3))*180/PI(),360)