Praying to Navagraha - Morning or evening

Hi - whats the best time to pray to Navagrahas, especially for Sani (Ellu Vilaku). Is it during the day time or late evenings after 7:00 PM?

I remember reading in one of the book we have to pray to Sani only during day time, but since childhood I've seen people light Ellu vilaku in the evenings only. am confused which is the right time. JFYI - my elarai Sani period is running now and Ahtama Sani for my daughter, Arthashtama Sani for my husband and I go through various issues everyday and by the grace of God am managing so far but at times am giving up and tend to loose my faith.

am worried if I'm doing something wrong in my prayers or something is missing, Your suggestions will help me gain back.

Thanks in advance

Praying to Navagraha - Morning or evening