How to use this chart: Hold the chart with one of the cardinal directions (North, South, East or West) down. The circle at the edge then represents the horizon, and the centre of the chart the point directly overhead. The sky is shown as it would be seen on April 15, at 9:00pm. Eastern.Daylight Saving TimeFuture charts may be obtained at http://aries.phys.yorku.ca/~blake/teaching.html Chart prepared by R. M. Blake, York University Observatory. Permission is given to reproduce this chart for non-commercial purposes. ©2000, R. M. Blake.