Shoot the sky

6 months ago in Ko Samui I had a rather abortive attempt at photographing the night sky;  a complete failure mainly due to leaving the attempts too late in our trip and having to face the problem of light pollution and an almost full moon in the only dark area I could find to place the camera.

The other major problem was my lack of understanding about the few simple rules that are essential when taking photos at night.

So the last few days of our trip to South Africa had us staying in the Western Cape outside of Citrusdal on a farm where light pollution wasn’t a problem as we really were in the middle of nowhere and at night you couldn’t see any light from Citrusdal (population 5,000) as it was 6km away and the other side of a mountain. These are the surroundings of the farm and show the regrowth of the vegetation after a fire last year raged for 5 days across the whole Citrusdal region.

So what are the basic rules for taking pictures of the night sky? I guess they are different for different skies and effects – but if you want to capture the stars and nebulas behind them in sharp pin point clarity – then there are a few rules.

The first to take note of is the rule of 600.

For this you divide 600 by the length of your lens in millimeters and this will give you the maximum exposure you can use without the stars moving.

Obviously the wider the lens the longer the exposure and the more light you get in your image.

(This 600 rule is for 35mm film and so I assume you will need to use different numbers for different formats).

For me this meant 600 / 24mm = 25 seconds maximum exposure.

The next step is to open the aperture to the maximum and so I used 2.8 on this lens.

And finally, use the fastest film that you can – and it was here that a complete lack of forward planning let me down again, as the fastest film I had was ISO 400 and there was no way I was going to be buying a fast film in Citrusdal.

I didn’t want to push the film (Portra 400) as the increase in grain would take away the sharpness of the stars I hoped to capture.

These are a couple of what turned out to be okish but definitely not great photos of the sky around us where I was trying to get the maximum 25 seconds out of the exposure by counting in my head (not very accurate I know).

The moon was half full and over behind me leaving the view I was taking in complete blackness. I assume the light on the leaves on the tree are reflected light from the moon.

The light in the bottom half of the image looks like light pollution but there is seriously nothing but mountains in this direction for many miles, so i am not sure why this came up.

The exposures were too long with my counting not being as exact as you need to be if you don’t want the stars to move in the image.

I should also admit that i wasn’t traveling with a tripod and so these were taken with a gorilla pod and a cable release on a Nikon FE – with me lying on the dirt to look through a view finder that just looked completely black…hence the poor framing.

What was most amazing about the results was that as I sat there in the dark, counting in my head to 25, I could only see 10 or 20 stars in total and I assumed the photos where going to be quite empty. I definitely couldn’t see any of the clouds of stars that appear in the image.

Even though the images are not massively sharp or well framed – they make me want to take these lessons and some really fast film to a remote area and do much more night sky photography. The next time I am going to be better prepared with a tripod and also having checked the night sky using Stellarium (a great free program for checking the sky where ever you are). I used the program for these shots and so knew I wasn’t going to get the Milky Way into these shots but that is something I am looking to get onto some shots in future night time trips.

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20 Jan 2012