Skip to main content (Press Enter).
Official Website of the United States Navy
Mission & Vision
Naval Oceanographic Office
Fleet Numerical Meteorology & Oceanography Center
United States Naval Observatory
News from the Naval Observatory
Earth Orientation Department
USNO Earth Orientation Products
Contents of Bulletin A
USNO GPS Products
GPS User Information
USNO VLBI-based Products
VLBI Correlator Data
VLBI-based Earth Orientation Parameters (EOP)
Earth Orientation Information Center
General Information about Earth Orientation
Frequently Asked Questions About Earth Orientation
What Is Earth Orientation?
What Is Polar Motion?
What does the Earth rotation coordinate measure?
What is the Celestial Pole Offset?
What is a Leap Second?
How do we measure Earth Orientation?
What causes variations in the Earth's orientation?
Who uses Earth orientation information?
Publications About Earth Orientation Products
Earth Orientation Software
Precise Time Department
The USNO Master Clock
The USNO Master Clock
Time Dissemination at the USNO
USNO Alternate Master Clock (AMC)
Cesium Atomic Clocks
Hydrogen Masers at the USNO
Rubidium Fountain Clocks
USNO Time Scales
International Time Scales and the BIPM
Definitions of Systems of Time
Global Positioning System
Global Positioning System Overview
USNO GPS Data Categories Explanation
CGGTTS Data Format
USNO GPS Time Transfer
GPS Information: SA, DGPS, Leap Seconds, etc.
GPS Week Number Rollover
GPS Timing Data and Information
USNO Format Explanation
USNO Computer Display Clocks
Two-Way Satellite Time Transfer (TWSTT)
Network Time Protocol (NTP)
US Eastern Time Zone NTP Servers
US Mountain Time Zone Servers
DoD Customer Servers
Astronomical Applications Department
Celestial Reference Frame Department
Senior Enlisted Advisor
Naval Oceanography Operations Command
Fleet Weather Center - Norfolk
Fleet Weather Center - San Diego
Joint Typhoon Warning Center
Public Use of Limitations
United States of America Department of the Navy Seal
The Sky This Week
U.S. Naval Observatory's Weekly Blog
Happy Solstice Celebrations!
by Geoff Chester, USNO Public Affairs
21 December 2021
‘Tis the Night Before Christmas and up in the dome
We eagerly wait for the nightfall to come.
The slit has been opened, the lens cap’s been stowed
The night sky awaits like a wide-open road.
The Moon is now waning through spring’s rising stars
By dawn on the New Year she approaches red Mars.
Last Quarter Moon on the 26
Then wanes to a crescent as morning light calls.
The solstice just passed on the 21
The Sun’s southernmost point on his orbital way.
The year’s longest nights are upon us right now
But they start to get longer when the Yule log’s aglow.
The Great Winter Circle shines bright in the night
With bright stars a-twinkling with all of their might.
Their colors add contrast to enhance the dark sky
While far down below they’re a treat for the eye.
Bright Venus still dazzles in eve twilight’s dusk glow
She soon will be quickly removed from the show.
By New Year’s she’s close to the bright solar glare,
You’ll find her in mornings throughout the next year.
Jupiter shines in the early eve’s light
With much fainter Saturn much harder to sight.
Old Jove seems to linger as next year begins,
While Saturn sets early from orbital whims.
Orion is rising high in the southeast,
Shield raised in defiance of Taurus the beast.
The Great Winter Circle surrounds his bold shape,
While faithful dog Canis leaps up in his wake.
Late night brings Sirius, the Dog Star on high,
By New Year’s he transits as midnight draws nigh.
The brightest of stars warm the long winter’s night,
His cohorts all add to the breathtaking sight.
Nine of the brightest of stars in the sky,
Light these dark nights of winter as Old Sol plays shy.
But the solstice is past us and now we are glad,
For the days getting longer than the ones we’ve just had.
The stars of the springtime rise late in the night
With a singular bright one to cause you delight.
Arcturus appears in the northeast late night
Then climbs ever higher by twilight’s first light.
The first stars of summer rise just before dawn
With the faint glow of Mars just tagging along.
The red planet lingers throughout the whole year
Then brightens to dazzle when next Christmas is here.
So Peace to your families, neighbors, and friends,
We wish you the best that the holiday sends.
The stars mark the comings and goings of time,
So stop to enjoy them, and so ends my rhyme.
Happy Holidays from all of us at the U.S. Naval Observatory!
DoD Accessibility/Section 508
No Fear Act
Plain Writing Act
Veterans Crisis Line
DoD Safe Helpline
Commander, Naval Meteorology and Oceanography Command | 1100 Balch Blvd. | Stennis Space Center, Mississippi 39529
Official U.S. Navy Website