Yes it can be done - just open your calendar on a daily view and right click on the screen, then select customise current view. Click on the other settings button, then change the Time Scale field to a larger time eg, from 30 mins to 15 mins.
When you next open outlook it will just show your chosen hours filling the screen. The other hours are still there - just scroll up or down. It all depends on the screen size - if you still see unwanted hours make the time Scale even smaller. This also has the advantage of being able to type more info into each appointment.