Change Format for Tooltip

Hi id like that my tooltip show only Day name and star - end hour, how could i do that?
Now i got this template for tooltip:

var template = "<b>{text}</b><br/><b>Start date: </b>"; template += "<%= scheduler.templates.tooltip_date_format(start) %><br/><b>End date: </b>"; template += "<%= scheduler.templates.tooltip_date_format(end) %>"; sched.Templates.tooltip_text = template;

Id like that tooltip displays like this:

Thanks in advance