Computer Graphics, Linux and Everything…

I finally got a chance to shoot a timelapse of the stars at my father’s country house this week. And to make things even better, it was August 12th… the shooting stars night. I learned a few things this night.

1. To make a starfield timelapse, it must be dark, very dark. The tinyest light pollution from a nearby village will be amplified by the long exposures and be visible in the shot.
2. To make a starfield timelapse, it must be dry. On the banks of the St-Lawrence river, in August, the moisture condenses on the lens and you are lucky to get 50 frames before it happens.
3. To make a starfield timelapse, you must use a camera that has as little dead pixels as possible. Mine is getting old (Canon Rebel XT) and I discovered it has many, many dead pixels.
4. To make a starfield timelapse, 1 minutes exposure per frame is good, but not enough to see the Milky Way.
5. To make a starfield timelapse, it is preferable to see something in the shot like a mountain or a house. Otherwise, all you see is a few stars rotating. Those objects in the shot would also recieve light from the moon when it rises possibly creating a cool effect.

I used my new shiny timelapse machine for this one since it allows for longer exposure times than what the camera supports. It proved to be useful and is perhaps the only thing that worked as expected that night.

So here is the result. I made the mistake of shooting in RAW. I should have shot in jpeg and used the noise reduction function of the camera. When I saw the result, I didn’t bother to process it too much and remove the dead pixels and color-correct it. I just set the black point to clip the light pollution and the noise and trimmed the bad frames.

1 minute exposure per frame, 8 seconds between frames, ISO 200, 12mm, F4.

I consider it to be a failure. The stars you see that don’t move are dead pixels (or dust on your screen). Near the end of the movie, you see the stars dim a little. That’s where the humidity started condensing on the lens. In the hi-res version, we can see one or two shooting stars, but they’re not very apparent. I didn’t bother posting the hi-res version.

I wanted to leave the camera outside all night but when I saw the amount of condensation there was on the lens after only an hour, I stopped the whole thing. The next morning when I saw all the water condensed on my car, I was glad I didn’t leave my camera outside.