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Timekeeping and Calendars


Astronomical Firsts June 10, 2010

Radio Programs

Summer Solstice Marking time by the motions of the Sun June 20, 2017

Sunrise and Sunset Defining the day’s “bookends” June 17, 2017

Daylight Saving Time Springing into a new time March 11, 2017

Groundhog Day Shadow or sunlight for a famous rodent February 2, 2017

February The oddest month of the year February 1, 2017

Dog Days The dog days of summer August 13, 2016

Imperial Month The “imperial” months of summer August 1, 2016

Ides of March Beware the Ides of March March 15, 2016

Leap Day Leaping with the seasons February 29, 2016

Moon and Regulus Marking the rhythms of the sky February 21, 2016

To the Future! Traveling into the future February 18, 2016

Arrow of Time Going forward in time February 16, 2016

Big Dipper Clock Ticking off the hours of the night January 22, 2016

September Equinox Changing seasons — one way or another September 21, 2015

Moon and Antares Ticking off the hours of the night September 18, 2015

Lammas Splitting the difference on the calendar July 31, 2015

Leap Second Stretching out the month of June June 29, 2015

Canopus III Navigating by a bright star February 23, 2015

Moon and Mars Jet lag after a long trip November 24, 2014

Daylight Saving Time Saving daylight to save energy October 31, 2014

Star Time Setting your watch by the stars October 20, 2014

Autumnal Equinox One way to mark a change in seasons September 21, 2014

July Honoring a famous calendar maker June 30, 2013

Winter Solstice A changing calendar cycle December 20, 2012

Moon and Companions Nothing to fear in the morning sky December 7, 2012

Seventh Month Miscounting the months August 31, 2012

Relativity and GPS Keeping track of the entire world May 7, 2012

Leap Day Leaping into the modern calendar February 28, 2012

The New Year Bringing the calendar to heel December 31, 2011

Featured Images

Twilight over McDonald Observatory

A Civil Sky June 18, 2017

Postcard of the historic Elgin Watch Company Observatory in Illinois

Star Time October 25, 2014

Without Einstein's theories of relativity, GPS wouldn't work

Where Am I? May 8, 2012