This dojo example is a modified version of this stackoverflow answer that allows you to add custom time markers. It involves a little bit of calculations to get the right position.
This has one draw back, which is it does not have the built in functionality of moving down the scheduler as the time changes.
As far as I know, there is nothing that gives you control over their current time marker, and so I believe custom time markers will be necessary, if you need functionality of it moving down the scheduler, that will have to be a custom solution you implement.
(You could just have a timing function that goes off after so many seconds/minutes that just runs the function to calculate and place the marker to update it. Hmm, seems potentially easier than I thought originally).