Time Traveller

You thunder off up the street as people begin to emerge from buildings, armed and looking for someone to shoot. Bullets skim past you as you charge down the street and round a corner to where you left the time machine. As you clamber from the horse, you are horrified to see that there are one or two people poking at it, wondering what it is.

"Get away from there!" You bellow, brandishing the colt, "Go on, get out of here!"
The people are unarmed and at the look on your face and the gun in your hand, scatter out of sight. Relieved, you throw yourself into the machine and begin typing in the necessary details.

Where do you set the machine for?