Tuesday, May 10, 2011

Searching for the Milky Way

Updated 5/16/11: I'm home and have had a chance to process the images on my home computer. The images are greatly improved!

I am spending the week at my family home in Southwestern Nebraska. Something that I have been wanting to experiment with was star photos. I've been searching the web for sky and light tools and star photography techniques. I discovered that this week was at the end of a good "dark" cycle: the moon is rising and setting in synch with the sun. This provides for moonless "dark skies" that help make good star photos possible.

The other thing that I learned is that the Milky Way would be rising during the current dark sky period. Just like the moon and the constellations the Milky Way rises and sets. So I set out to take photos of this astronomical feature. Here are the results. The processes for capturing and post-processing I followed are after the images:

Milky Way - Northern Arm

Milky Way - Southern Arm

How did I do these:
- Camera: D7000 and Tamron 11-16mm f/2.8
- Settings: ISO 800, 30 second exposure, aperture f/2.8
- Post processing ACR and CS5

In ACR the images's exposure was boosted +1.0ev  +1.75ev along with applying Clarity and Vibrance adjustments.  Noise suppression was also done in ACR.  That converted image was then completed in Photoshop. There the image was built up as a composite of several layers of the same image and curves adjustments applied. The cropping was done in CS5.

I am very excited how these first efforts came out, with a degree of sadness about how difficult it is to find truly dark skies. I left the horizons in both of these photos to demonstrate how much light pollution there is in the night sky, even in rural Nebraska.  In the second processing I did crop out the village lights from "Southern Arm", but you can still see the effects of the light pollution.

I shot from near the top of the highest point in the county. The Northern Arm image is taken to the northeast, which to the naked eye is the darkest horizon. I also took advantage of the peak of the hill to try to block some nearer lights. But there is a large town, some 90 miles away, and a couple of smaller villages in that general direction. You can see the glow at the horizon.

The Southern Arm is the more dramatic section of the Milky Way, and to capture it I had to shoot to the southeast, in the general direction of a village and the farms in the valley. You can see how the glow actually prevents seeing the Milky Way all the way into the horizon.

I also want to call out the tools that helped me plan this outing:
- The Photographer's Ephemeris: this tool provides you with the times of the rising and setting of the Sun and Moon, as well as the various twilight times. It shows the locations of the Sun and Moon at the horizon and the elevation at different times of day. It also includes maps that allow you to plan when the sun will be striking a mountain or illuminating a valley
- SkyGazer: this is a astronomical star chart program. It will show you where the various stars, planets, galaxies, etc. will be in the sky at a given location and time.

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