Few can resist the natural beauty of a sunset and the beautiful colours – particularly in the autumn months – are truly sublime; deep blue vignetting into yellow, orange and red. Viewing the setting Sun without filters is not recommended as harmful radiation can still cause eye damage. A camera however, can fare better.
A good challenge is to produce a spectacular image of the Sun’s last moments before it slips beneath the horizon. There’s a special sunset on 11 November this year as Mercury will still be in transit at sunset.
As ever it pays to show caution. When the Sun is less than a degree above the horizon, the thicker layer of atmosphere its light has to pass through attenuates its output.
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It also scatters more of the blue end of the spectrum leaving the predominantly orange-red tones to dominate.
A safe way to achieve a camera view of sunset is to apply solar safety film to a telescope.
Remember to cap any finder scopes before pointing at the Sun, though, as failure to do this may result in their cross hairs burning out.
Once the filter has been fitted, point the telescope at the Sun and use your camera’s Live View mode to get a precise alignment.
Portsmouth’s Spinnaker Tower, silhouetted by the setting Sun – taken from 22km away. Credit: Pete Lawrence
Rotate the camera so the horizon is parallel with the edge of the camera frame.
Focus the image as best you can, zooming into the edge of the Sun’s disc.
This can be tricky to get right as the solar limb often appears to boil when the Sun’s altitude is low.
At your own risk, when the Sun has an altitude less than an apparent solar radius it’s possible to remove the solar safety filter and image directly.
Discretion needs to be applied here and if you’re not sure what you’re doing, don’t try.
If you do decide to remove the filter, do not look through the camera’s viewfinder and never leave the setup unnecessarily looking at the Sun if you’re not taking photos.
In such circumstances, simply reapply the safety filter until you’re ready.
Use your camera’s lowest ISO value and set the exposure to the fastest shutter speed. Take a shot and examine for over-exposure.
If the Sun’s disc is over-exposed, re-fit the filter. If the Sun is dim enough not to over-expose, adjust the exposure so the Sun appears bright but its disc shows colour and doesn’t appear white.
Sunsets are a spectacle in their own right, but with a bit of planning or simply by monitoring how the Sun moves from one evening to the next, it’s possible to enhance an image with a foreground silhouette.
If you are up to the challenge, it’s possible to achieve something truly spectacular.
This article originally appeared in the November issue of BBC Sky at Night Magazine. Pete Lawrence is an experienced astrophotographer and a co-presenter on The Sky at Night.