Ever look up at night and wonder what’s there?
Here’s a monthly guide to the celestial splendors of a dark night sky.
Our Dark Skies Star Guide is perfect for any area in the Northern Hemisphere where you can get away from city lights. This guide was written at the observatory in Ajo, AZ.
This is a beginner's book for anyone who wants find their zodiacal sun sign in the Night Sky, learn when to observe meteor showers, and how to find many cosmic mysteries up in the heavens with just your own eyes or an ordinary pair of binoculars.
No science or math background required. Fun and easy to read charts, diagrams, and large text you can read easily in the dark with a flashlight. There's even a detailed explanation of how to see the International Space Station - an object brighter than Venus!
Navigate the night sky any night of the year at any time.
This roadmap of the night sky and accompanying booklet shows the location of stars, planets and constellations in your night sky when you dial in the exact hour and date.
by Bill Georgevich, Chief Astronomer, Windowpane Observatory
Did you know that in its infancy, our universe was completely dark for more than 200 million years? When we visualize the origin of our universe as a Big Bang, it would be natural to assume that the newly expanding universe contained stars. But for the first 180 to 300 million years, the universe wasn’t illuminated by any light at all. That’s because stars were not formed until hot gas coalesced around clumps of dark matter. The gas contracted until it became dense enough to ignite the nuclear hearts of infant suns.
The ability for our universe to harbor any type of life is absolutely and completely dependent on the existence of stars. Stars not only form the elemental building blocks of matter that become planets, they also provide the molecular ingredients that form all life on this planet and many others.
A star is born when a cloud of gas grows dense and collapses from its own gravitational weight. An interstellar cloud of gas will maintain equilibrium (and thereby ever remain a simple gas cloud) as long as the pressure of its kinetic energy is in balance with the energy of its internal force of gravity. But if the cloud is massive enough, the expanding gas pressure will not be strong enough to support the cloud, which will then implode in a gravitational collapse. In the same way a hydrogen bomb compresses hydrogen into helium — releasing massive energy — so too does the force of gravity in a hydrogen gas cloud fuse hydrogen into helium, igniting the nuclear furnace we know as a star.
This fascinating close-up of the Horsehead Nebula was shot in infrared light and then color-enhanced to reveal the details of this active star-forming interstellar dust cloud. The shape of the Horsehead comes from stellar winds that have sculpted the cloud over time. Its shape will change over the next few million years and will eventually be destroyed by high-energy starlight, leaving behind a cluster of the young, maturing stars seen in the photo.
Around 250 million years after the Big Bang, the very first proto-stars lit up the dark expanses of space. In the 13.6 billion years since, trillions and trillions of stars have been born, giving us the night sky we enjoy today. But the story does not end there.
Stars are still forming in our universe, and they provide a unique insight into how our early universe transitioned from a completely dark, expanding shell of high-energy particles into stars, binary stars, and multiple-star systems — many with planets belonging to star clusters that live in the billions and billions of galaxies that inhabit our contemporary universe.
This extraordinary light-saber-like photograph (left) shows a proto-star forming in the Orion Nebula about 1350 light years away. Stars in their early inception sometimes shoot out jets like the one you see here. These jets are called Herbig-Haro (HH). This young star is known as HH 24, the 24th proto-star jet discovered in visible light. It lives in an animated cloud of dust and gas in the Orion Molecular Cloud Complex, a large and very active stellar birthplace. This stellar nursery contains over 100 known kinds of organic and inorganic gases, as well as dust; some of the latter is made up of large and complex organic molecules.
Magnetic fields channel the gases, blasting the nebula into streams, shown as streaks in the background glow. A glowing strip of hydrogen gas marks the edge of the massive cloud, and the densities of nearby stars are noticeably different on either side.
Many stellar nurseries are visible to the unaided naked eye in the very dark skies of Ajo, and we have featured them in this calendar. In the Winter, they include the Orion Nebula (which is naked-eye visible as the middle “star” in the scabbard of Orion), and the Rosette Nebula (which sits left of Orion in the constellation Monoceros, or the Unicorn). The Summer Milky Way is resplendent with several naked-eye visible stellar birthing places, including the Lagoon, Trifid, and Omega nebulae.
To learn more about how to locate these stunning stellar nurseries, be sure to read our book Ajo Dark Skies Star Guide with an accompanying rotating star chart, which is a map of the sky for any night of the year.