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Dr. Reiff was instrumental in the design of the Cockrell Sundial at the Houston Museum of Natural Science (HMNS), calculating the hour/month lines and inventing the special silver ball on the top of the dark gnomon. That ball creates Houston's special "stonehenge", casting an image of the sun near solar noon for a week or two around the equinoxes and solstices, allowing easy viewing of sunspots. First opened in September 1989, the sundial has kept perfect "solar time" for more than thirty years.

Sundial Events

We will be hosting live and online streaming events for every solstice and equinox at the Cockrell Sundial at the Houston Museum of Natural Science. CHECK THE CALENDAR for information and to register for these events.

Past Events


Cockrell Sundial at HMNS

The following documents are courtesy HMNS and the Rice Space Institute and may be freely copied for non-commercial educational use.

Cockrell Sundial Timelapse

720x720 fisheye MP4

1280x720 flat MP4