Not blinded by light pollution, the first humans undoubtedly looked up at night in wonder, even as we do today from dark-sky locations, and saw a sky full of stars. They saw that the Sun moved across the sky during the day, and that the Moon and stars followed a similar path at night. Other bright "stars", that we now know to be planets, also wandered among the stars, changing position against the starry background.

When civilization first developed thousands of years ago, the timings of the rise of certain stars and constellations were used to predict the coming of the seasons, and the planting and harvesting of crops for food. Getting this right was important in sustaining these different civilizations, and led to the development of astronomy. With astronomy, people could keep track of time. The Sun marked days, and the phases of the Moon marked months. The first rising of Sirius, the brightest star, before the Sun, marked the span of a year. Keeping track of time was also important in the observance of religous holidays.

Early civilizations in the near and far east in India, China, Egypt and Persia, as well as the Maya in South America and the American Indians in North America, began to develop astronomical observatories to follow the events in the heavens, keep track of time, and to facilitate their predictive abilities for the timing of the seasons.

The Geocentric World View

Some early astronomical world views, and the most famous philosophers of the time, such as Aristotle and Ptolemy, believed that the Earth was the center of the universe and that everything revolved around it. This was called the geocentric model.

An illustration from Harmonia Macrocosmica by Andreas Cellarius, 1708, shows the Earth at the center of the universe in the geocentric model.

But even as early as Aristarchus in Greece around 200 B.C., some believed that the Earth and planets revolved around the Sun - the heliocentric model. In general though, this philosophy was rejected for the next 1800 years, in particular by the Catholic Church.

Copernicus' Heliocentric World View

In 1543, Nicolaus Copernicus published De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), and showed that the motion of the planets could be predicted by assuming that the Sun was the center of the solar system instead of the Earth.

An illustration from Harmonia Macrocosmica by Andreas Cellarius, 1708, shows the Sun at the center of the solar system in the Heliocentric model of Copernicus.

Copernicus' book marked the end of the dark ages in Europe, the birth of modern astronomy, and the start of the scientific revolution. Galileo used one of the first telescopes to discover and publish astronomical evidence to support Copernicus' heliocentric world view in the early 1600s. At the same time Kepler published his laws of planetary motion which stated that the planets orbit the Sun in elliptical orbits instead of circular ones. Galileo used his telescope to discover the moons of Jupiter in 1610. He also discovered the rings of Saturn, and confirmed the phases of Venus. He also observed craters and mountains on the Moon and spots on the Sun. For publishing his opinions and supporting heliocentrism, which was contrary to scripture, Galileo was found "vehemently suspect of heresy" by the Inquisition, and arrested and ordered imprisoned by the Catholic Church. He spent the rest of his life under house arrest. Galileo was a towering figure in the history of modern science and father of the scientific revolution where reason and knowledge replaced superstition and fear. The scientific method sought to explain the world by observation and collection of data, the formulation of hypotheses to explain observed phenomenon and make predictions, and their objective experimental testing. A key part of the scientific method is that predictions made by a theory must be testable, falsifiable, and repeatable. Unlike faith, the scientific method allows for the possibility that a theory can be wrong, and if contradictory evidence is found, a theory can be modified or rejected. The telescope proved to be a very powerful instrument for the advancement of astronomy and a tool in the scientific method because it allowed observers to see things fainter, and with more magnification, than the eye could see. In the late 1600s, Sir Isaac Newton put forth his theory of universal gravitation and three laws of motion, which erased the last doubts about Copernicus' heliocentric theory because they worked so well to describe actual observations of the motions of the planets. Newton explained Kepler's law of planetary motion by positing the existence of an attractive force called gravity that existed between the Sun and planets. The Invention of Photography In the 1820s, photography was invented, and the first permanent photograph taken by Joseph Nicephore Niepce in 1825. The first astronomical photograph, a daguerreotype of the Moon, was taken by Louis-Jacques-Mande Daguerre on January 2, 1839, but it did not survive a fire that destroyed his laboratory and most of his photographs. In 1850, William Cranch Bond and J. A. Whipple, took the first photo (a Daguerreotype) of a star, Vega. In 1880, Henry Draper took the first astrophoto of a nebula, a 51-minute exposure of the Orion Nebula. In 1883, A.A. Common made a 37 min exposure of the Orion Nebula with his 36 inch telescope that was the first photo that showed more than the eye could see through the same telescope. Common also took the first photograph of the Andromeda galaxy in 1884. But it wasn't until more than 75 years after Draper's photo that William C. Miller took the first accurate color photo of a deep-sky object, the Veil Nebula, in 1957. As with the invention of the telescope, photography would open tremendous new vistas in astronomy. As the telescope allowed observers to see things too faint to be seen with the unaided eye, photography allowed astronomers to see things too faint to be seen visually in a telescope. Modern Physics and Cosmology In 1905, Albert Einstein published papers that would revolutionize physics and our understanding of the world in terms of space, time, and matter. His theories on the nature of light, and special and general relativity, overturned the world view of classic physics. They brought us into the world of quantum mechanics, which we still don't completely understand more than 100 years later. Einstein's theory of general relativity predicted that light would be deflected by the massive gravity of a star. Following the scientific method, his theory was first confirmed by photographs of the 1919 total solar eclipse. Many subsequent experiments in the following years continue to confirm this theory. Edwin Hubble used photographs in 1924 to identify Cepheid variable stars in the spiral "nebulas". His observations proved that these "nebulas" were too far away to be part of our own galaxy, and that they were, in fact, other galaxies. This discovery profoundly changed our view of the universe. Later, Hubble added observational support for the Big Bang theory and the expanding universe by photographing the red-shifted spectra of galaxies. In 1998, astronomers discovered that the expansion of the universe was actually accelerating, a very surprising finding that rocked the scientific world. This discovery was also made photographically by studying supernovas in distant galaxies.

Nicolaus Copernicus Galileo Sir Isaac Newton Joseph Nicephore Niepce Louis Jacques Mande Daguerre Albert Einstein Edwin Hubble

Astronomy and Astrophotography - The Bottom Line Since its invention, photography has played a key role in the development of modern astronomy. Many of the most important discoveries in astronomy have been made photographically, first with film and now with digital cameras. Photography has also played a pivotal role in many other scientific discoveries. Long-exposure deep-sky astrophotography allows us to record things that are too faint to be seen visually, and it gives us access to a remarkably beautiful and wondrous universe.