Sunday, January 3, 2010

Winter Skies

"Happiness is nothing more than good health and a bad memory." (Albert Schweitzer)

Now that it's January, I'm starting to come around to consider whether or not to think about the possibility of maybe trying out a New Year's resolution. I don't wanna' rush into anything.

I'm thinking that a good resolution for me might be to put off procrastinating. If I just wait a little bit longer before not doing things, then maybe I could forget more of the things that I didn't get around to doing.

Like this video, for example. I put it together less than a year ago. Okay, it was 11 months, three weeks and a couple of days ago. We had a rare, clear night sky last winter, so I set the camera (Nikon D200) out on our deck where I could plug it into AC power. (Winter air temps kill batteries in short order.) My planning also included me curling up indoors, under our electric blanket, while the camera did all the work.

Personally, the only major drawback to living at the end of the road (i.e. in Montana) is the preponderance of gray in winter. The short winter days feel even shorter when there's gray overcast for weeks on end. I read about winter meteor showers, and look out the window. Gray. I follow the lunar cycles, anticipate new and full moons and, when I look out the window, still gray.

On the other hand, winter is what keeps Montana from turning into another, say, California. I've worked in some beautiful back country in the Golden State, but I'm thankful that all of the Californians live there and not here. If Montana became that crowded, I'd have to move to the Yukon Territories. They don't have political parties up there, and they enjoy frequent northern lights.

Oh yeah, the video. I almost forgot.

I'd been meaning to put together a short video on startrails for some time. Sort of an educational tool. I find nighttime photos fascinating, but about 90% of normal people (i.e. non-photographers) who see my startrail photos don't have a clue what they are. Meteors? Airplanes? Scratches? So I put this video together during a lull last winter, and then I promptly forgot about it. Sorta' makes me wonder what else I've done.

In this particular video and composite image (top), there are four things going on. Foremost, the Earth is rotating, which makes the stars appear to move across the sky -- the constellation Orion makes a late appearance. Also, the moon rises partway through, which lights the fog rolling in, and across the frozen lake the neighbor's yard light paints the fog orange.

Now, there are two ways to create a startrail photograph. You can take one long, single exposure, as in the good (not great) old days of film. Or you can take a series of short exposures, one right after another, and then combine them into a single composite image. This video is the latter method, but I actually prefer the former.

Stars on the water of Lake McDonald, Glacier National Park (c) John AshleyOne long, single exposure seems to give me more variety on star/planet size and color. I don't know why that is. But digital cameras are draining batteries during the entire exposure, so you can only go about an hour (depending on temperature and body) on 4-8 AA's . That's because, with digital cameras, the sensors get hot and start to create all kinds of digital fog and noise. So I also have to use the noise reduction feature in my Nikon bodies, which automatically takes another exposure of equal length immediately following my star trail exposure. That means a one-hour exposure is followed by (approximately) a one-hour noise reduction exposure, and two hours in the cold is really pushing your luck with AA batteries.

Each generation of camera bodies improves on battery life -- my D700 lasts much longer than my D200s -- but we'll still be pushing the envelope until we have a digital body that can go 12 hours or more on one battery.

A creative photographer friend in England tried using the extra grip with dual batteries, and "hot-swapping" fresh batteries into the grip during the exposure. He tells me that it works for him, but I'm not that brave. I don't want to sit out in the dark all night only to find out, later on, that I jiggled the camera halfway through.

Set up for startrails and jumping dead car batteries (click to enlarge)So I cheat. I bring a bigger battery. I use an AC adaptor for the camera, plug the adapter into a small inverter, and plug the inverter into one of those car emergency-jump-start batteries they sell at Costco. The cheesy little adapter from Nikon costs as much as the inverter and battery combined, and the whole jury rig runs about $200.

The cheaper and easier method is to combine lots of short exposures into one composite image. My digital Nikon bodies have a great feature called "image overlay" that I use a lot for moonbows, but it's tedious if you are combining more than 10 or 20 images. You can also stack short startrail exposures in Photoshop, but that gets laborious as well.

For a good startrail composite, you'll be combining 200 to 400 images. Consecutive 30-second images means 120 frames per hour, so three hours of trailing requires 360 images. For this size project, I use freeware from Achim Schaller in Germany called, oddly-enough, "Startrails" ( It's simple, easy to use, and it works well.

For this stacking method, and this video (remember the video?), I use a remote cable to lock the camera down on 30-second exposures. My ISO usually hovers between 200 and 400 (on the D200, higher on the D700), and I usually stop-down whichever lens by one stop to make me worry less about soft corners.

Short startrails with in-camera batteries only, Mount Robson, the highest peak in the Canadian Rockies (c) John AshleyBut like I said, the video is just an educational thing. I normally go the one-long-exposure route. I try to make the image more meaningful by including a lake or some recognizable mountain in the foreground. Funky old buildings, church steeples and the like would also make interesting foregrounds, but I'm just not that kind of guy. I am surprised by how many people go through all the work to create a startrail photo just to stick some boring, anonymous tree tops in the foreground.

None of this information is new, most of it will probably become obsolete after one or two more rounds of new camera bodies from Nikon and Canon. I can't wait to see Nikon's response to Canon's latest volley.

I'm an old and forgetful Nikon guy, but if you haven't yet seen what the new Canon EOS 1D Mark IV body can do, prepare to have some brain cells scrambled. The short video, "Nocturne," was shot at ISO 6,400 with a 35mm DSLR! (also see, "Behind the Scenes" of Nocturne). This new body records HD video, and reaches into the stars with a maximum ISO of 12,800. Of course, the price is also astronomical (US $4,999).

Unbelievable. Just imagine the expanding possibilities for startrails and other kinds of astrophotography. Mark my words, there will be an explosion of mind-bending nighttime photography in the next couple of years. Maybe I should have waited a little bit longer and just forgotten about my little video.

Happy New Year, and happy (star) trails to you...

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