Ask HN: What's the best time to post to HN

Does anyone know what's the best time to post to Hacker News to achieve the most visibility?

I live in the UK so I'm guessing the best time for me to post is around 5pm. That way people in the UK may read my post plus I know there is a large user base in the U.S especially on the West Coast. For them it would be 9am and they will be just starting their working day.