Due to the interest in the star trail images I have posted on social media over the last week and people asking me how they were achieved, I thought I’d write about the story behind one image in particular and how it was achieved though both are shown here as stills and the first, also, as a time-lapse sequences.
Having photographed Elmley NNR in all seasons and weathers, there has always being a nagging feeling of not having ever successfully photographed the reserve under a night sky. There are number of reasons for this, namely that surrounding much of the reserve there is quite a bit of light pollution and, also, that Elmley is not at an easy place in which to work given that it is a flat, almost featureless landscape and so locating a suitable structure or foreground is not an easy task.
The motivation behind the image was both the so called ‘supermoon’ and Perseid meteor shower that occurred between the 10th and 13th of this month with it peaking in the early hours of the 13th. Normally, a full moon would be your enemy in astrophotography as it brightens the night sky but, instead, I used it to my advantage by looking for a location where the moon would illuminate the landscape. With the ‘shower’ occurring in the north-east part of the sky it was, of course, imperative to point the camera in that direction which also had the added benefit of the stars rotating around the polar or North Star.
In order for the resulting image to be put into context I knew that I needed something in keeping with the Kent marshes and in my mind there is nothing more so than the endless cattle fences that criss-cross this expansive landscape. On my first night I thought I had found such a place but unfortunately the shoot was thwarted by drifting cloud (even though the forecast was for a clear sky!) which I hadn’t noticed as I drifted in and out of sleep from the relative comfort of my car 50 metres away.
With the following night, once again, giving clear skies and my final chance to potentially capture a meteor with star trails I headed back to my original spot. As I arrived I noticed cattle had moved ever closer to where I was going to set up so thought better of it and looked for somewhere else. As I walked through the long grass towards another cattle fence I saw the composition I had been seeking all along. Better, I thought, than the previous nights, too.
By 9 o clock the camera was in position but this, of course, was far too early to trigger the camera. On the three forecasts that I checked online each had stated that there would be clear skies from between midnight and 1am onwards and with that in mind I set the Interval Timer on the Nikon D600 to shoot continuously from 1am until either the cards (one in each slot) were filled or battery power was exhausted which was unlikely given that I had a battery grip attached giving an additional battery worth of power. With everything in position there was nothing I could do except go home, collect the camera the following morning and hope for the best.
Technical details
Nikon D600, Samyang 14mm f2.8 lens, ISO 200, 30 secs. f/2.8, Manfrotto 055 tripod with Markins B1 ball-head.
Exposure
So, how did I know what settings to select? On my first attempt I arrived at around 11pm with a full moon shining brightly. I did a test shot at ISO 100, 30 secs at f/2.8 but found it to be a little underexposed so I, simply, increased the ISO to 200. Taking the 30 second exposure into account and time for each image to load onto the memory card I set the interval between shots to 35 seconds. 35 secs. minus 30 second exposure = 5 second interval which gave sufficient time for each image to load onto the memory card.
In total, I used 300 frames that were taken between 1 and 4am. The RAW files were then processed in Lightroom and the whole thing put together using Startrails.exe software with final tweaking done in Photoshop CS4.
Some of you may be wondering why I took so many individual images as opposed to just putting the camera on B (Bulb) setting and leaving the shutter open. There’s two very good reasons for that. As it was full moon, anything longer than 2 minutes would have resulted in gross overexposure and also, by shooting multiple frames you have the option of producing a time-lapse sequence as illustrated below.
I must admit, that while Startrials.exe was building the image I thought the white streak was an aircraft. It was only when it was completed that I could see that, actually, it was a meteor from the Swift-Tuttle comet.
This one was taken between 12 and 4am comprising of 400 frames. An image I have had in my mind's eye for a very long time required me to plot the precise location of the polar star in order to get the trails of all other stars rotating around it.
