Stars Over Chichester Cathedral
Note there is no Exif info for this shot as the Startrails stacking software removes it.
This shot was pushing to the limit with Star Trails. Normally Star Trails are taken as far as possible from light pollution. However I knew from pictures on flickr that it was possible and the available foregrounds are really worthwhile. The most important thing is to aim the camera up and avoid street lights in the field of view. To avoid an over yellow look I followed some advice on the web and set the WB way down to 2700k.
This was taken from the back of the Cathedral which enables the North Star to be in the view. Also it is hidden from direct street lighting. Also with the Cathedral closed it is a dead end and well out of sight of any wandering yobs
The star trails turned out better than I expected. It was not possible to see on the screen whether any stars had come out. Also the right exposure for the stars overexposed the floodlit Cathedral. I took some pictures first exposed for the Cathedral and then while keeping the Tripod in the same position changed the settings and started the star exposures.
I had particularly wanted to make the best of the weather as on this day and the previous few days there were totally clear skies 24 hours a day with record breaking summer like temperatures in late March. It was close to the edge for good Star Trails with the Moon in the Evening sky at a quarter crescent and waxing larger.
For Star Trails there are 2 methods, either one long exposure of 20 minutes plus or a lot of shorter exposures later blended together. The problem with the first is if something goes wrong such as a walker with a flashlight or condensation you can lose the whole thing so I always go for the second. It would normally be very time consuming to blend all the pictures together but there is now free software available to do it for you at www.startrails.de/html/software.html
With the method of stacking together shorter exposures noise is not such an issue so I turned off the Cameras noise reduction settings. If these are turned on it doubles the exposure length as a second image is taken automatically of the same length for the noise reduction process. Noise was corrected later with software. Also a higher ISO is required to get the stars to register in 30 seconds so I used ISO 640 and f4.5. I usually use ISO800 but in this urban area I tried 640.
The circular pattern is formed by pointing the camera towards Polaris the Pole Star near the Plough. As the Earth turns stars more above the pole do not appear to move as much as those more above lower latitudes. I had with me an HTC Android Smart Phone with the Google Sky App. This enabled me to locate the pole star while there was still light.
The foreground comprises 2 images combined in StarTrails.exe exposed for the foreground.
It is normally necessary to wait for Astronomical Night which on that night was about 2 hours after Sunset when the most stars are visible. I used wunderground.com for the location which has an Almanac section which includes that. This is the time when all light from the sun has left the sky and the maximum number of stars is available. However with light pollution cutting down visible stars anyway for this shot I started at 9.00 pm.
The beam of light is the floodlight lighting up the Spire.
The image was taken over 60 minutes with 120 images of 30 seconds exposures each stacked with the startrails software. I set the camera to continuous mode and used a wireless shutter release to lock the shutter so the exposures were taken continuously without needing to touch the Camera
- Sony A700.
- ISO 640, f4.5, 30 seconds, 10mm.
- WB set to 2700K for Urban Area
- Sigma 10-20 lens.
- Wireless Shutter Release
- Arrive early, bring a compass or Smartphone, to help find the north star.
- Setup gear while it’s still light, get your composition and wait.
- Shoot test shots, check light, make sure you can see the first stars.
- Wait for that perfect moment, then start the exposure.
- Bring a torch, so you can find you way and make adjustments after dark.
- Bring warm clothing and a snack and drink.
I processed the Cathedral and Star Trails separately. For the Star Trails the stacking software works on jpegs which are then saved as a Tiff. This was opened in Photoshop. It was easy to select just the sky with the quick selection tool.
I first used Topaz Adjust Vibrance presets, Detail strong 2 with some adjustments to further bring out the Star Trails. Noise reduction also applied in Topaz.
General adjustments in curves and contrast layers to enhance the star trails.
Noiseware Pro and then Clarity effect, Unsharp mask 60 amount and 60 radius,
For the foreground I first used Topaz Adjust Vibrance presets, Detail strong 2 with some adjustments to bring out more detail in the Cathedral.
Adjustments were made in a Curves layer and Vibrance plus 16.
The sky selection was pasted into the Foreground image and the Move tool used to line up. Slight tidy up with the Clone Tool.
For Licensing and more pictures see Edwin Jones Photography