I went on field trip to Tenerife when I was at uni, to look thru telescopes at stars & stuff.
The day started at around 6am, but our flight was delayed so we didnt get to our accommodation till just intime for the evening meal, then we were straight out onto the telescope for the first night.
Worked thru till 6am, and no matter how tired you are going to sleep at 6am is impossible!
I think it was about 30 hours in total, seemed like much longer I suppose cus of the travelling.

I got no more than 3 hours sleep a night (a day I suppose) that whole week.