Fortunately, I was able to get online here 10 minutes or so ago. Since it was the perfect time to get the "Mortarboard" badge, I tried if I would get one by hitting the reputation cap as soon as the day commences. However, neither I nor any other user got the badge as I have rechecked from the list of users who have the badge. What is the time zone used?
I believe that "hitting the reputation cap" means earning (any amount more than) 200 points in a single day. This is the cap that is set, and any reputation earned above 200 is not actually awarded (excepting points for accepted answers and bounties). So it's not clear how one could easily plan to hit the cap at the commencement of the day, except by planning to provide some truly outstanding answers, that would earn more than 20 votes.
The time is GMT (or UTC as it is called nowadays) and starts at midnight. See: When does timing start for evaluating badges that are obtained based on daily activity
There are 61 people who got Mortarboard on the main site, according to this: https://math.stackexchange.com/badges/41/mortarboard
On meta, there are 8: http://meta.math.stackexchange.com/badges/41/mortarboard
Mortarboard is only awarded once. So if you have got it once, you won't get it again.
btw, questions like these really ought to be asked/searched for on meta.stackoverflow.com