You are here

Timekeeping and Calendars


Astronomical Firsts June 10, 2010

Radio Programs

Falling Back Recouping an hour of sleep November 2, 2019

Dog Days The Dog Days of summer August 17, 2019

Oddest Month The oddest month comes to an end February 28, 2019

Groundhog Day Celebrating Groundhog Day February 2, 2019

Standard Time Falling into Standard Time November 3, 2018

Nabta Calendar markers in the Egyptian desert June 20, 2018

Moon and Spica A star with an important history May 25, 2018

Martian Autumn A new season for the Red Planet May 22, 2018

Groundhog Day Lighting the coming spring February 2, 2018

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

Featured Images

Time machines

Time to Ponder September 20, 2019

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