The Science of Exploration Through Photography – Durango Herald

The Science of Exploration Through Photography – Durango Herald

Greetings, stars.

In 1995, the Hubble science team released the “Pillars of Creation” image. This image radically changed the way most of us think about astrophotography. Yes, the high resolution and image detail were very impressive, but it was the color palette that made this image unique. I’ve written individual columns about nebulae, astrophotography, astronomical filters, and a bit of spectroscopy, but these topics all come together to create these “custom color” photographs.

The Pillars of Creation are part of the Eagle Nebula, which was discovered in the 18th century, and is the 16th object on Charles Messier’s list of “mysterious objects that are not comets.” It was first photographed in the late 19th century and was a regular target in the late 20th century for astronomers using film cameras. While the first images were black and white, color film could produce some amazing images that would match (at least somewhat) what we might be able to see with our naked eyes if they were sensitive enough.

Because the Hubble Telescope was primarily a scientific mission, there was great interest in studying the formation of the universe by looking at specific wavelengths of light. Each element has its own unique spectral signature, or fingerprint, so looking for a specific wavelength of light associated with a particular element will reveal the distribution of that element. For example, excited hydrogen atoms emit a prominent red line at 656 nm, and taking an image through a filter that passes 656 nm light will show the distribution of hydrogen atoms.

Narrowband filters are manufactured by building multiple layers of dielectric coatings onto a glass surface. These coatings are the same anti-reflective coatings you can get on your glasses, but with specific thicknesses and layers, specific wavelengths of light can be allowed to pass through, while others are reflected.

Instead of just looking at one item at a time, it is possible to associate an item with one of the red, green, or blue parts of a three-color photograph. In what is now called the Hubble panel, the sulfur line is designated in red, the hydrogen line is designated in green, and the oxygen line is designated blue.

Narrowband filters are now readily available, although they are not cheap. As the quality of digital cameras has improved over the past two decades, the quality of narrowband images taken from Earth has also improved. Narrowband images are easier to recognize because of the bright colors, rather than the overall purple tones of hydrogen gas seen in “natural” light.

As the use of the Fort Lewis observatories continues to expand, I hope that more of these narrowband images will be produced locally.

Hubble image updates

https://hubblesite.org/contents/news-releases/2015/news-2015-01.html

Astronomy photo today

http://apod.nasa.gov/apod/

Astrology forecast for Durango

http://www.cleardarksky.com/c/DrngoCOkey.html?1

Old Fort Lewis Observatory

http://www.fortlewis.edu/observatory

hakes_c@fortlewis.edu

This month

  • Jupiter and Saturn are in an ideal place in the southern sky for observation with binoculars or a telescope this month. Even for small telescopes, both planets are great targets to look at. Jupiter was at opposition, at its closest point to Earth, on November 3.
  • Uranus at opposition on the 13th. Although it is not usually included as one of the “visible” planets, Uranus can be seen with the naked eye from a dark location. Now it is between Jupiter and the Pleiades. Binoculars will make the job much easier, but don’t expect more than a blue-green dot, even with a large telescope.
  • Venus is a bright morning star. You can see it during the day, because it is definitely bright enough. Its position relative to the sun will not change during the day, so if you observe how far it is from the sun at dawn, it will remain at the same distance throughout the day.
  • The Leonid meteor shower reaches its peak on the nights of the 17th and 18th. There are expected to be about 15 meteors per hour this year, caused by dust from Comet Tempel-Tuttle, or twice as many as on a night without a meteor shower.

Charles Hakes teaches in the Department of Physics and Engineering at Fort Lewis College and is director of the Fort Lewis Observatory.

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