Ashes to Ashes *Explored*

At this risk of becoming one dimensional my photostream has featured lots of sky shots lately, this is the last of my Milky Way shots....for a while anyway!!!! This one is different from the others, shot with my 50mm manual prime lens @F2.4, Seven horizontal images stitched together in PS. Each image was a 5 second exposures at ISO 12800.

So why the relatively short exposure and high ISO, I hear you say!!!lol It's a bit technical, a 50mm lens on a cropped sensor gives an image which is similar to a focal length of 75mm lens on a full frame 35mm sensor. The larger the focal length the closer to the stars you get, obviously! The closer you get to the stars the more they will move in your frame. Stay with me!!!!As you take a photo of the stars, the Earth is moving, an exposure over 20 seconds at 18mm's on a cropped sensor camera will result in slight movement of the Stars and cause Star-trails. Stars will become triangular in appearance. There is a formula to calculate what time exposure for the focal length of your lens so as to avoid the movement of the stars. It's something like 450/focal length of lens (in full frame, 35mm format) For my 50mm lens this would be a 6 second exposure. I opted for 5 seconds and just pushed my camera's ISO to the limit.

I have a lot more to learn about shooting the stars and what I'm actually capturing. This image contains so much, it is hard to know what to start labeling. When you start to think about it, it's humbling to think how isolated we are on this little rock, which is for us, the center of our universe!


Pentax K-x, 5 sec, ISO 12,800 @ 50 mm (7 horizontal shots)


Click here to see my astro set

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Taken on August 14, 2012