Continuous Monitoring of Comet Holmes from Before the 2007 Outburst

The outburst and subsequent brightness evolution of Comet 17P/Holmes has been observed using the MMT Observatory’s All-Sky Camera (Pickering 2006) on Mt. Hopkins near Tucson, Arizona, USA. The comet was picked up at the limiting visual magnitude of 5.5 on October 24.38 and tracked by the camera continuously until sunrise four hours later. During this time the comet brightened to visual magnitude 3.5. Comet Holmes was next observed just after sunset on October 25.23 at visual magnitude 2.5 where it remained approximately constant over the next three days. The comet then began to dim slowly and was followed into the early months of 2008 with periods of dense time coverage.