Wednesday 12 March 2014

Painting the sky

Stand still! Don't move! ready? By the time you read this you already moved 300 Km. What?! 

The movements of our planet are awesome, even more when you don't have this in your mind and you suddenly realize that even without moving a muscle you're traveling through the universe at unbelievable speeds.

The Earth rotation around it's axis is the most expected movement. The Earth rotates around its axis at about 0,5 Km/s but at the same time we're moving around our star, the sun, at 30 Km/s. The sun itself, and us with it, is moving around the center of our galaxy, the milky way at 250 Km/s and our galaxy is also moving at more than 300 Km/s taking the local group of galaxies as reference. Mind blowing, right?

Most of these movements can only be pictured in our imagination but the Earth rotation can be perfectly felt on a clear night. This same rotation is the reason why the astrophotography is so tricky requiring expensive mounts to cancel this rotational movement.

Picturing this movement can be done by nothing else than a camera and a tripod. Taking a lot of long exposure shots and adding them together will show it. Even more, if you point the camera aligning it with the Earth axis you'll get the following...


This image is composed by 300 shots of 25s, ISO 3200 at 18mm f3.5 with the kit lens of my Nikon D3100, stacked with StarStaX. Probably with a full frame the ISO can be lowered a lot and even the exposures leading to a less noisy image but I'm particularly happy with the image and this will be a good memory of my travel to Asturias.

After building this image, I realized that with so many shots, it was possible to build a video with them. These videos built from static shots are called timelapses. Every 25 shots will build one second of video so you can summarize 3 hours of action in a couple of seconds. This coupled with the ability of the program used to stack the star trail to save every intermediate stacked picture lead to this video.

The BSO is the beginning of "The Waltz of the Flowers" by Pyotr Ilyich Tchaikovsky.

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