Today's early sky

kw: photographs, available light

At 5:30 this morning I went out for the paper and noticed that the fast-moving clouds were just starting to get a bit of pink. Sunrise was more than an hour away. I ran in and got the camera and a tripod. The camera is a Nikon D40 with the "kit lens", the AF 18-55mm. It doesn't have indicators for the distance when in manual focus, and it focuses beyond infinity, so I had to put it in manual focus and guess at the setting.

I used Shutter mode and took a 25-second shot. That was overexposed, so I did a second one at 10 seconds, this one. The light in the sky is what astronomers call "civil twilight", when it looks dark to the eye, but there is too much light for good astronomy. You can see a star or two coming through the blue. A look at the larger version of this pic will reveal that I set the focus rather badly. I plan to learn more about setting focus manually before the next such opportunity.

This is the same image, with the gamma shifted to 0.33 and the contrast reduced a little, so that it looks more like what I could see by eye. There is still probably more blue here than I could see, but the pinking in the clouds is about right. The dim light on the house is from a street light across the road. And of course, without thinking I ran out without closing the front door.

I hadn't tried night shooting before. I used to do it with ASA 800 film, but at an exposure of a second or longer film suffers from a lot of reciprocity failure, probably dropping to an effective ASA of 400 or 300. A digital sensor has no reciprocity failure, so I think the top image is a genuine ASA 800 exposure.

I've had ambitions of putting the camera on my telescope's clock-driven mounting and trying for wide-angle star shots. It is definitely sensitive enough to capture views well beyond what the eye can see. I'll have to try it soon.