Astrophotography and the Orion Nebula
Astrophotography is a great way to explore and share the celestial objects viewed through a telescope. Ever since the development of digital camera technology, astrophotography has become much less time consuming compared to film and more accessible to the amateur astronomer.
Results are almost instant, allowing for more experimentation with camera settings during the same imaging session. With film cameras, the film had to be developed the next day only to learn that the two hours spent capturing a galaxy the night before ended with a blurred image due to tracking problems unknown at the time. The digital camera, with its ability to gather light much faster than film, allows a number of images to be attempted, reviewed and corrected within the same imaging session. It takes some doing initially, but once the telescope and camera equipment is in place and working properly, it is relatively easy to get decent images.
Digital cameras are also much more sensitive than the human eye in detecting color. When looking through the eyepiece of the telescope, faint objects appear dull and colorless because our eyes have a difficult time detecting color in dim light. When a camera replaces the eyepiece on a telescope, it is able to capture the color otherwise hidden from us. There are a variety of subjects to choose from for astrophotography and a favorite subject of many astrophotographers, professional and amateur alike, are the nebulae. Nebulae are vast, colorful regions of dust and gas spanning many light years across. Some nebulae are stellar nurseries, giving birth to new stars. Other nebulae are the result of old stars in their final years ending in massive explosions called supernovae, or quietly expelling their outer layers of gas into the surrounding space producing what we call planetary nebulae.
Arguably the most spectacular and easiest to locate nebulae in our sky is still visible this time of year. The Great Orion Nebula is located just below Orion’s belt in the constellation Orion found in the southwestern sky in the early evening after sunset. A known stellar nursery, it has more than 150 newly forming solar systems as identified by the Hubble Space Telescope. The many colors visible in photographs of the Orion Nebula originate from the different gases that are either radiating their own light due to energy from nearby stars or reflecting the light of more distant stars.
Visible to the unaided eye on a moonless night with favorable skies, it appears as a small, fuzzy, gray patch just below the three stars that make up Orion’s belt. In the eyepiece of a telescope, it appears in more detail showing a vast, gaseous structure along with an apparent group of four stars forming a “trapezoid” shape. This group of four stars commonly referred to as the “trapezium,” is actually comprised of six stars and the extra two stars can be seen with a moderate telescope under good viewing conditions. Unfortunately, capturing those stars in an image usually requires shorter exposures with the camera which reduces the amount of the gaseous nebula visible in the image. On the other hand, taking an image which shows the faintest regions of the nebula usually results in an overexposure of the central stars. In order to achieve the best of both, more involved techniques are required but even the most basic methods can produce stunning images.
Recently, the Orion Nebula was the subject of an astrophotography session at the Adirondack Public Observatory. Images of the Orion Nebula taken during that session can be viewed on the APO Facebook page and one take by APO Board member, Seth McGowan is shown. This was the first astronomy image he ever made and he used a Nikon DSLR. The Adirondack Public Observatory web page (www.apobservatory.org) and APO Facebook page also have other examples of images taken by amateur astrophotographers over the years. When you go to those sites keep in mind that many of the images were taken by people with just a basic knowledge of astronomy and photography.
The APO will offer our third annual Astrophotography Workshop forum Oct. 19-22, 2017. Three instructors will offer instruction in a variety of photographic techniques at a variety of levels, as well as astronomical topics over this four-day workshop. It’s intended for both beginners lacking equipment and experienced astrophotographers. Please see our web page for more details.
The astronomers of the Adirondack Public observatory will be happy to share views of the Orion and other nebulae from our RORO above Little Wolf Pond in Tupper Lake. We’re open to the public on the first and third Fridays of each month, weather permitting. For updates and notices, check out our website at adirondackpublicobservatory.org and our Facebook page. On our public observing days you can also call the RORO at 518-359-6317 to talk with one of our astronomers. Observing starts about one half hour past sunset.