Locations, Mapping, Calendars, Sun
Jantar Mantar, India
Berkeley, California, USA
JoAnn Gillerman © 1995
JoAnn Gillerman © 2021
measures time of DAY
measures time of YEAR
Cahokia Mounds / Monks Mound
Horizon Calendars / Native American
Chichen Itza, Mexico
Solar Calendar / Mayan
Solar DAY - 24 hours (Interval between two passages of the Sun across the meridian is a solar day)
Solar YEAR - 365 days (Time interval for Earth to complete an orbit around the Sun)
Calendar: system of organization usually based on astronomical periods of time:
Days, Weeks, Months, Year
Summer Solstice (June 20 or 21) - longest sunlight day of the year and shortest night - Earth's North Pole is tilted toward the Sun and the Sun reaches its highest point in the sky.
Winter Solstice (December 20 or 21) - shortest amount of sunlight day of the year and the longest night - Earth's North Pole is tilted farthest from the Sun.
One Synodic (phases of the Moon) Month is determined by the Moon's passage once around the Earth and is about 29 days
The meridian is the (imaginary) great circle (on the celestial sphere) passing through the celestial poles as well as the zenith (highest location directly above the observer) and nadir (180 degrees opposite zenith) of the observer's location. It contains the north and south points on the horizon, and is perpendicular to the celestial equator and horizon.
Meridian and Horizon Calendars
What do these locations have in common?
Which location is most interesting to you?
What do you find interesting about your favorite location?
Can you draw this location?