Dawn is a critical and exciting time for the natural navigator, it sets up the day. It is also a time of rapid change, I took the second of these two photographs only one hour after the first yesterday morning, but that need not catch us off guard.
With experience it is possible to tell that this moon is two days off a new moon, which means that it will rise two of my fist-widths (24 degrees) ahead of the sun. The sun travels through the sky at just over a full fist width (15 degrees) an hour. It was therefore possible for me to gauge that the sun would rise in about one and half hours just by looking at the low moon in a dark sky.