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Sunday 23 December 2012

POTD Exmouth Star Trails

I know its been a while since the last Picture of the Day, so I thought we would star back off with some star pictures. In my rear garden I have this weather vane attached to my garage so I decided to use it as the foreground interest, luckily for me the vane has rusted a little so is stuck in position.

Using my tallest tripod set to maximum height I managed to get my Nikon D3 and 14-24mm lens as close as I could it the vane and on the 14 end of the lens I could get a good field of view of the sky. The camera has a built in interval timer (you can get cable releases with built in timers which can be purchased pretty cheap on ebay check this one foe Nikon here). I set the time gap at 15 secs and the number of images at 200, the exposure was set at 3 secs at f2.8 on ISO 3200. I then left the camera to run its course.

Below is just one of the images, you have to try and keep the under 10 seconds because of the speed that the Earth rotates you with start to get movement in the stars.


Once I have all the images onto the computer I then used a free program called Startrails for PC or Starstax for MAC user, you load in the images and it blends the altogether. You should end up with something like the image below. I also pointed the camera at the North star to give a central turning point.



Similar as what what I said before about the speed of the Earth turning you also need to keep your gap between picture around 5-15 seconds. Below is an earlier examples of mine where I had the gap set to 30 seconds.



You can see the gaps that have appeared in the lines.

You will also notice on the stacked image a single dots that is not in the center  when I looked back through the images it only appears in one. I noticed it a bit more when I loaded all the images in Adobe After Effect and played them out on a time line.


After some discussion we think it was probably a meteorite as if it was a shooting star it was probably appear in more than one shot.

What do you think?

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