Photos: Incredible pics of the heavens, taken from Seattle's corner of the galaxy
The clear, dark winter skies might allow for some frigid temperatures, but for local astronomers, it's the best present Mother Nature can bring.
Steven Rosenow, of Loowit Imaging in Shelton, Wash., has been braving single digit temperatures and some gusty winds each night during our arctic snap this week to take his telescope out and capture some incredible images of what lies beyond.
"By the time I got done (Wednesday) night, I had a telescope and camera setup that had a very thick layer of frost," Rosenow said.
The skies have to be clear, and calm winds are a big help. Some of the photos in the gallery were taken Tuesday night when winds were gusting to 25-30 mph. Not only does that make for a nasty wind chill, but you need to keep the telescope still.
"The wind has a tendency to vibrate and shake my telescope a bit, making the task of deep sky photography a bit hard," he said. "Basically, it makes stars look like they've developed a case of the squigglies so to speak."
The photos are certainly a labor of love, requiring 1-2 hours of equipment setup and each photo requiring several minutes of extended exposure shots and processing.
And patience. Tons of it.
"To get a decent final exposure on a deep sky target, you need at least an hour or two's worth of exposure on it," Rosenow said. "And that's not holding the shutter down for that hour or two, either. You take multiple exposures (some do two, others do five minute exposures, and some even longer than that - all of which require extreme patience manually guiding on a star or using autoguiding cameras and software) of the same target, usually at ISO800 or ISO1600 (no higher, typically, as higher ISO tends to throw a lot of noise).
"After that, a series of calibration frames are taken, the two most important are called 'darks' and 'flats.' Darks are basically reshooting your target, with the same exposure settings, but with the lens cap over the telescope to create a black image. This is used to remove the SNR (signal to noise ratio), and then you take a piece of white cloth over the telescope's lens or corrector plate and shoot a series of flats. Those are shot usually with the output being a gray image, and those remove vignetting or dust motes on the sensor."
Rosenow has been trying to shoot the heavens since Oct. 2007, when Comet 17P/Holmes came along. He just got a new telescope and decided to try his hand at astrophotography on the comet. Most of his shots didn't pan out, but one did, and it had him hooked. He's been honing his craft ever since, learning the skies by star hopping and by reading star charts.
And not only has he developed countless photos, he's developed somewhat of a hatred of clouds.
"Let's say I'm not a fan of the rain all the time. ;) The skies in the Pacific Northwest were recently rated the second worst in the country for astronomy by Sky and Telescope magazine, and I wish they were better," he said. "The last four months were brutal, with almost nonstop clouds and rain. The summer before wasn't better, with smoke haze from fires in E. Washington polluting skies on our side.
"So it's easy to see why, during a night of biting cold and clear skies, you'll find a hearty astronomer such as yours truly, standing out at the telescope until daybreak, taking advantage of every photon available. :) "
Rosenow shared his latest group of photos here in the blog and he's given an extensive description of each star/nebula in the caption. You can find more of Rosenow's work on his Loowit Imaging Facebook page.