he·li·a·cal 
(hĭ-līə-kəl)
(hĭ-līə-kəl)adj.
Of or relating to the sun, especially rising and setting with the sun.
[From Late Latin hēliacus, from Greek hēliakos, from hēlios, sun; see sāwel- in the Appendix of Indo-European roots.]
he·lia·cal·ly adv.