What did the evening sky look like for Benjamin Franklin, Thomas Jefferson, and their contemporaries on July 4, 1776?
As the United States marks its 250th birthday, many astronomy enthusiasts may be asking exactly that. If you stepped outside around 9 p.m. local time on July 5, 1776, the sky would look much as it does today. Only careful measurements would show that the stars were not in quite the same positions they occupy in 2026.
To understand the sky more fully, it helps to look at how people in 1776 tracked celestial events and what they would have expected to see overhead.
But first, how did people in 1776 keep track of astronomical phenomena? People studied astronomy for practical reasons both in and out of the classroom. It was essential for navigation, surveying, timekeeping, and charting unfamiliar lands. In an age before light pollution, ordinary people were also likely far more familiar with the stars and constellations than most people are today.
Almanacs: timetables of the heavens
In the American colonies of the 17th and 18th centuries, an almanac ranked just behind the Bible in everyday importance. It listed sunrise and sunset, moonrise and moonset, the times when bright stars reached their highest points in the sky, lunar phases, planetary positions, some astrological lore, and practical information such as road conditions, husbandry tips, and weather forecasts.
By the early 18th century, numerous almanacs were in print. Many survived only a few years, but a bestseller could support its printer well into the following year. Among the most successful was Benjamin Franklin's "Poor Richard's Almanack", published in Philadelphia under the pseudonym Richard Saunders from 1732 to 1758. It became immensely popular, selling more than 10,000 copies annually. Franklin has often been called America's first true Renaissance man — an author, printer, politician, diplomat, inventor, and scientist who counted astronomy among his interests.
Later, yearly "prospectuses of the sundry celestial events" could be derived from the extensive calculations appearing in "The Nautical Almanac", established in 1766 by Dr. Nevil Maskelyne, the fifth Astronomer Royal of England.
The planets visible over the U.S. in 1776
For anyone consulting an almanac for the year 1776, they would find that only one planet could be readily viewed after sundown. Saturn, in the constellation Virgo, passed opposition to the sun on April 7 and during July would be evident in the southwest sky at dusk, shining with a yellowish-white glow and appearing slightly brighter than the bluish first magnitude star Spica, about 7 degrees to its lower left. On the evening of July 22, a waxing crescent moon would appear to form a broad triangle with Saturn and Spica. Of course, Saturn's most notable telescopic feature is its ring system, which at that time was tilted 10 degrees from edge-on with its north face in view.
Toward the end of the month, three other planets would be available about 90 minutes before sunrise, low in the east-northeast amidst the stars of Gemini: Mercury, Jupiter and Mars. Dazzling Venus would be invisible due to its proximity to the sun.
The great lunar eclipse of July 1776
The month's most anticipated astronomical event was the total lunar eclipse of July 30. By the standards of most eclipses, it was exceptional: totality would last an unusually long 1 hour 35 minutes. Unfortunately for observers in Philadelphia, New York, Boston, and many other locations, much of the spectacle unfolded before moonrise. Mid-totality was predicted for "7:01 o'clock in the evening," before the moon rose, and the moon would begin emerging from Earth's shadow at 7:49 p.m., when it was positioned just above the east-southeast horizon. It would "quit the shadow completely" at 8:48 p.m.
The eclipse came just 26 days after the Declaration of Independence was unanimously adopted by the Second Continental Congress in Philadelphia. It was widely observed and discussed in journals of the era and later became part of Revolutionary War Lore. In a time of profound uncertainty, early Americans watched it closely despite poor viewing conditions. Diarists and observers, including hymn writer John Newton and militia officers, often treated the event as an omen reflecting the gravity of the Revolution. The Declaration of Independence was engrossed on parchment, and delegates began signing it on Aug. 2, 1776, only three days after the eclipse.
Beyond the month's most dramatic event lies a subtler question: whether the background stars themselves would have looked meaningfully different from the way they appear today.
Did the stars look different 250 years ago?
Besides rotating and revolving, Earth has an oscillating motion like that of a spinning top due chiefly to the pull of the moon on Earth's equatorial bulge. Each oscillation takes about 26,000 years. Thus, the North Pole traces a circle in the sky, pointing to different stars as it moves in its circuit.
Consequently, Polaris wasn't as good a pole star in 1776, being 1.88 degrees from the celestial pole compared to 0.63 degrees today. Put another way: the gap between the celestial pole and Polaris measured nearly four moon-widths in 1776 compared to just over one-width today.
What about proper motion? Have any stars shifted noticeably in 250 years? The only one would be the brilliant orange star Arcturus in Boötes, which has the largest proper motion of any 1st-magnitude star, but since 1776 has drifted only about 0.13 degrees (equal to about one-quarter of a moon diameter) with respect to its fainter neighbors.
The weather on America's first Independence Day
One final detail adds historical texture: the weather in Philadelphia on July 4, 1776, was pleasant and mild, with clear morning skies giving way to increasing clouds by afternoon. Weather journals kept by Thomas Jefferson and local observer Phineas Pemberton record a high of 76° F. Those later clouds, however, might have obscured much of the sky on that first night of Independence.
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer's Almanac and other publications.
