December 14 – December 27, 2015
Mt. Washington — Enter a star nursery in the Orion Nebula, thousands of trillions of miles from Earth. We journey there through the art and science of astrophotography. From Earth, the nebula, also known as M42, is visible with our own unaided eyes as a smudge of light in the constellation Orion the Hunter. On these, the shortest, darkest days of the year, Orion, one of the largest and most well known star patterns, rises in the east a few hours after sunset and sets in the west a few hours before sunrise. In most locations, including cities, Orion can be identified by one bright star above and one below a “belt,” a row of three evenly spaced stars. In dark sky locations, away from artificial lights, a “sword” can be seen as a diagonal line of stars hanging from the Hunter’s belt. The nebula is the bright glow in the middle of the sword.
In the phenomenal images shown here we see gigantic clouds of cosmic gas and dust that are lit by “monstrously massive stars.” Among students of the cosmos the Orion Nebula is one of the most studied of deep space phenomena. Astrophotographer Kent DeGroff’s image reveals four great stars, known as the Trapezium, deep inside a well of blue light – a stellar nursery – surrounded by hydrogen gas. The fireball, above left, is M43, another area of star formation. DeGroff describes the photographic process as follows: “A series of images are taken using a black-and-white camera with color filters. These are then combined to form the final picture showing details of the distribution of elements in the nebula. Different filters are used to bring out different details, thus the vastly different appearance of the same object in different photographs.”
I became acquainted with Kent DeGroff through membership in the Silver City Astronomical Society. He photographs under the clear, dark skies near the Gila National Forest in southwest New Mexico. DeGroff recommended me to Terry Hancock’s photograph, the vivid rose-colored sphere suspended in glowing, wispy cosmic clouds and a starry field. This image of the Orion Nebula was published as Astronomy Picture of the Day (APOD) by the National Aeronautics and Space Administration (NASA) on November 4, 2015. According to DeGroff, Hancock’s image “covers the three bright naked eye stars of the sword of Orion.” DeGroff’s close-up of the red sphere takes us inside the nebula, as does the third nebula picture, which was imaged through a collaboration of the Hubble and Spitzer space telescopes. Note that in Hancock’s picture M43 is oriented differently from the other two nebula photographs.
When I asked Kent if these photographs were false color, he replied, “It is definitely false color, being adjusted to show a maximum amount of detail. To the eye through a telescope, it [M42] appears mostly greenish and relatively faint. To images taken using red, green and blue like a color camera, it is mostly reddish — due to the preponderance of Hydrogen-Alpha radiation which is a deep red. It is an extremely involved process to produce a good color picture. I take many images in the three colors, which must be combined by stacking to produce a color image. That image then requires a lot of adjustments to make the details of the object appear.”
The winter solstice is on Monday the 21st at 11:48 p.m.
Resources:
https://www.flickr.com/photos/whiskey_creek_observatory/
https://www.downunderobservatory.com/about-me.html
*https://apod.nasa.gov/apod/ap091222.html
https://apod.nasa.gov/apod/archivepix.html
https://astronomyconnect.com/forums/articles/terry-hancock-astrophotographer-profile.10/
https://cosmicpursuits.com/e-books/armchair-astronomer-volume-1-nebulae/
