I have a self register either an IWB one or names on the ground. The children register themselves then they either get a book or play with some blocks i set out. Once all the children are there they sit on the carpet for 15 mins max while we do all the morning stuff such as what day is it month weather etc etc before they have centre activities. I'm also sure that the other teacher in your team wiuld not mind you observing or even asking her morning routine if you can't observe. Most teachers are open to people asking!!!