Learn how to shoot the night sky as we show you how to set up your camera to photograph star trails and stack your images in the digital darkroom.
Star trail photos, with moving stars forming streaks of light across the night sky, are always popular. In this tutorial, we’re going to walk you through how to shoot source images for a star trail photo, and then how to merge them in Lightroom.
If you’re in the northern hemisphere, you’ll need to aim for Polaris, the north star, to achieve the classic ‘circular’ star trail look. If you’re in the southern hemisphere, you’ll need to find the south celestial pole .
A big part of photographing the night sky successfully is having low light pollution and clear, cloudless skies, so first we had to do a bit of research to find a really dark sky, and a clear night on which to photograph.
The Brecon Beacons, in South Wales, became only the fifth International Dark Sky Reserve in the world back in 2012, and prides itself on having extremely dark skies. This made it the perfect location for us to photograph our star trails.
The weather in Wales is notoriously changeable, so we kept a close eye on the forecast and made sure we were all packed up and ready to go as soon as an opportunity presented itself.
Finally our patience was rewarded by a small window of clear weather, so we made a beeline for South Wales before the weather closed in again.
We scouted a few locations first in daylight, so we could get all set up before it got dark, and then we were ready to start shooting…
SEE MORE: Best camera settings for astrophotography
Set up your camera to shoot star trails
Clear skies
Check the light pollution and the weather before you go, and pick a location that will be clear of clouds and unwanted lights.
Winter warmers
Wrap up warm. Your camera also feels the cold, so take a towel or hand warmers to wrap around the lens and avoid misting.
Night vision
Bring a pocket light, and make sure it’s red or has a red filter. Using a red light will help you keep your night vision (see top left).
Twilight zone
Get set up to compose your scene. This will be difficult in darkness, which is why recceing the location beforehand is important.
SEE MORE: Milky Way photography tips for the first time astrophotographer
Finding true north
01 Navigate with a compass
Compose your photo with Polaris in the centre (for circular shapes) or off to one side for beautifully curved star trails, as in our shot. To find Polaris, take a compass reading to locate north, then aim your camera in that direction and slightly up, and look for the brightest star.
02 Map the stars
You can find true north even if you don’t have a compass. You will need to know at least one constellation, though, and that’s Ursa Major (‘the plough’). Find the end of the ‘pan’ part of the shape (see above), then plot an imaginary line up from the edge of the pan to the very next bright star.
SEE MORE: How to track the sun for perfect landscape photos
How to photograph the stars
01 Hold still
We used a bungee cord to tie our bag to the tripod to stabilise it in the windy conditions. When shooting long exposures, keep the camera as still as possible. Anything you can do to steady the camera is a good thing. A bungee cord takes up little space and is worth throwing in your bag.
SEE MORE: How to eliminate camera shake: practical tips for avoiding blurry photos
02 Focus manually
The AF system won’t have enough light to focus properly so you must focus manually. If there are distant lights, focus on these, then recompose. If not, get a friend to stand 40 to 50 feet in front of the camera and point a light towards you, focus on the light, then recompose.
SEE MORE: Manual focus: what you need to know to get sharp images
03 Warm the glass
Keep your lens warm to prevent it misting up as the night gets colder. We wrapped our lens with a heated hand warmer and a small towel, with a rubber band to hold it around the barrel. Be careful not to knock the focus ring when wrapping your flannel around the lens barrel though.
SEE MORE: 10 ways to maintain the health of your camera
04 Get set up
Set your lens to its widest aperture. The stars are so far away a shallow depth of field won’t make any difference to the focusing of the shot. Set a shutter speed of between 20 and 30 seconds at ISO 200 and take a test shot. If your shots are too dark, increase the ISO.
SEE MORE: Night Sky Photography: pro secrets for stunning moonlight landscapes
05 Expose to the right
If your location suffers from light pollution, try the ‘expose to the right’ technique. Take a shot and check the histogram: you want the graph to stack up to the right-hand side, but without clipping. This should allow your sensor to capture more detail. You can correct the exposure in post-production.
SEE MORE: Expose to the right: the camera technique every landscape photographer must know
06 Start your sequence
Open the intervalometer setting in your camera’s menu. If your camera doesn’t have this feature, use an external intervalometer to set the number of shots. The number will depend on how long you want your trails. We set 200 shots at an exposure time of 30 seconds each.
Quick tips
• No stars sit as perfectly in the south as Polaris does in the north. To locate the south celestial pole, find the Southern Cross and draw an imaginary line from the top to the bottom, and then extend it about four times
• Use an ultra wide-angle lens to fit more sky in your photos, and don’t forget to include some foreground to give your photos some sense of location
• Instead of shooting a sequence of hundreds of short exposures and merging them in Photoshop, it’s perfectly possible to shoot a single, super-long exposure of an hour or more, but the longer the exposure, the higher the noise in the resulting image.
This is because image sensors generate heat from their own electrified circuits, and the sensor records this heat/electrical interference as noise. As such, it’s best to keep exposures below one minute and then stack them in editing software.
SEE MORE: 8 ways to get sharp photos at night
How to stack your star trail images
01 Import your shots
Go to File>New Catalogue. Name your catalogue Star Trails and click on Save. The (empty) Library window will open up. Navigate to your images, select them all, press Cmd/Ctrl + A, and drag them onto the grey import area. Click on the import button in the window that appears.
02 Edit as needed
Move to the Develop module. On the right hand-side you’ll see the tool panel. Starting from the top, switch the white balance to Tungsten, to alleviate the light pollution. Add fill light to brighten the midtones, and then increase the vibrance to boost the colours without clipping them.
SEE MORE: Adobe Lightroom: how to use the Develop module for serious photo editing
03 Export to Photoshop
Select all the photos in the filmstrip by going to Select>All and clicking on the Sync button. Tick Check all before clicking on Synchronise, and these adjustments will be applied to all the selected images. Click on Edit, then choose Photo>Edit In>Open As Layers in Photoshop.
04 Merge the trails
The images open on separate layers. Drag the first image you took to the bottom and set blending mode to normal. Select the top layer, change the blending mode to Lighten, then right-click and pick Copy layer style. Go to Select>All layers, right-click on any layer and pick Paste layer style.
SEE MORE: Non-destructive editing: how to use adjustment layers to fine-tune images
05 Add a mask
If you have any aeroplane light trails, or extraneous light leaking in, add a mask to the layer in question, grab your Brush tool (press B) and paint with black to eliminate the distraction. Be careful not to brush out the stars as well, as this will result in gaps in the star trails themselves.
SEE MORE: Layer mask techniques anyone can do: master this vital Photoshop effect
06 Save it
You’re nearly done. Now you just need to save the image. Go to File>Save As and choose a suitable file type –JPEGs are usually the most useful. Give the picture a file name and click on Save. Your image will export, giving you the final photograph.
Noise pollution
If you find your images do have lots of noise, don’t worry because you can reduce this in Lightroom. Go to the Develop module, and in the Detail panel (at the bottom-right of screen – you may have to scroll down), under Reset Noise Reduction move the Luminance slider up until the noise is acceptable.
Final Tip
Change your white balance to Tungsten. This will remove the orange cast made by any nearby light pollution
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