Tuesday, 16 November 2010

Orion Nebula - Astrophotography

It was Astrophotography that originally got me into photography.  Once you spend x amount on a DSLR you quickly find that only using it on clear dark nights (few and far between here in the UK) is not using it to its full potential.  However the shots that you do get when the nights are clear, tracking mount works as it should, alignment is spot on and the laptop doesnt shut down because of the freezing cold nights then the shots that you can get are quite literally out of this world.  

Orion Nebula, Canon 1000D attached to an C80ED
Above is a shot of the Orion Nebula and the Runnng Man near the top this was achieved by attaching the camera to a telescope (basically just acts as a really big lens) via an adapter.  Using the LiveView functionality of the camera attached to a laptop you can focus on a bright star and then set the camera to manual mode and for this shot I set the shutter speed to be 13 seconds long and I had the ISO at 800 which was the sweet spot for the camera good light sensitivity and low noise.  This shot was composed of 50 of these shots and then using some very clever software (DeepSkyStacker DSS) stacked on top of each other allowing the random noise to be evened out while enhancing very faint details.  Stacking allows the photographer to create photos that would normally require very long exposures and super accurate tracking to avoid blur.  Even if you could manage to take a very long exposure of say 60 seconds or greater you then have the problem of light pollution having a very large affect on the shot, unless you are lucky enough to shoot from a very dark location.

If you are interested in doing some basic astrophotography then even without a telescope you can get some pretty amazing photos of the night sky, by placing you camera on a tripod point towards the night sky, set the camera to manual mode.  Set the shutter speed to be around 10-15 seconds, aperture to as wide as you can (lowest f number) and a resonably high ISO 400-800 higher if you know how noisy the sensor is.  Once you are ready to take the photo either use a shutter release cable to  avoid camera shake or a little tip if you dont have one is to use the cameras 2 second timer.  You may need to tweak these settings but you should see that the amount of stars you capture is incredible you may even get the hints of a galaxy like M31 the Andromeda galaxy or the Milkyway band showing.  Try combing multiple shots using DSS mentioned above to get even more detail and play around with the curves in Gimp or Photoshop to enhance the detail further.

If this is something you are interested in the give me a shout and I will post some tutorials and details on this and other shots.

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