Astrophotography may sound difficult; however, this really isn’t the case once you’ve learned the basics. When you look up at the beautiful stars above your camp site or travel destination, wouldn’t it be nice to keep them as a photograph?
As the very first step in astrophotography, we will introduce fixed-mount shooting using a digital SLR camera fixed to a tripod.
Best conditions for astrophotography
For astrophotography, there are a number of best practices that differ from those in daylight conditions.
To capture the night sky beautifully, the surrounding environment is of utmost importance. In urban areas, artificial light illuminates the night sky – so strongly that even bright stars are difficult to be seen. It is important to choose a location that has low light pollution. The clarity of the sky will also impact the quality of the photograph, so choose a day when the air is clean.
The phase of the moon
If you head out into the mountains to avoid artificial light, the moon will distract you from watching the stars when it is bright. One week before or after the new moon, when there is little moon light, is the best period for astrophotography shooting.
Choose a fine day with no clouds
It goes almost without saying that the prime condition for photographing the stars is that the sky is clear. Check the weather forecast beforehand.
Equipment for astrophotography
Here are a number of items required for astrophotography.
For beginners, a wide-angle lens with a focal length shorter than 35 mm (FX/35mm-format equivalent) will be easier to handle. Ideally, choose a fast (with a small f-number), fixed focal-length lens that has good performance from the maximum aperture, but you could also try the wider-angle of your own kit lens. For example, the AF-S DX NIKKOR 18-55mm f/3.5-5.6G ED VR II will be 18 mm (equivalent to 27 mm in the 35mm format) at the maximum wide-angle position, so you can capture the stars with the landscape in a wide perspective.
AF-S DX NIKKOR 18-55mm f/3.5-5.6G ED VR II
The lens hood stops excess light from entering the lens. It also helps prevent the condensation that often occurs when shooting the stars.
Because the night sky is too dark, your camera’s auto exposure and autofocus functions will not work. Everything needs to be set up in manual. It is best practice to check the “M” (manual) position of the mode dial and the position for setting the lens to manual focus in advance.
Batteries drain more rapidly in astrophotography because you are taking long-exposure shots in the cooler environment of the mountains. Be sure to take a spare battery with you, not just in winter but in summer as well.
A tripod is an absolute must for taking long-exposure shots over a few seconds to capture the night sky. Pick a solid one so it won’t be shaken by the wind. The same goes for the tripod head*. A universal head allows you to freely arrange and change the composition.
* Tripod head helps mount the camera to the tripod legs, and allows you to change its rotation or lock it to a desired position.
To prevent camera shake during long-exposure shots with slow shutter speeds, use a remote control or a remote cord. We recommend Nikon’s ML-L3 Remote Control and the MC-DC2 and MC-36A Remote Cords (optional). Use the Exposure Delay mode to set the shutter to release approx. 1 to 3 seconds after pressing the shutter release button.
• Use the camera’s self-timer to substitute the Exposure Delay when using a camera without that function, such as the D3300 etc.
• Check the product web page of each remote for compatibility.
You’ll find a headlamp more convenient than a torch because it frees up your hands. Red light LED is recommend as it preserves your dark-adapted vision.
Other useful items
Night dew can easily build up your lens during night shooting. A dew-covered lens blurs your star image. One effective way to prevent condensation is warming your lens by wrapping it in a dew heater.
Use a compass to find Polaris. As the Polar star shines due north, it shows you where the celestial north pole is. Once you know the position of the Polaris, the other stars will be that much easier to find.
This is a handy tool for determining the current position of the stars visible in the night sky. You’ll also be able to check star-rise and star-set for the constellations.
Binoculars help you spot the celestial objects you’re aiming for, and guide your camera, with a longer focus lens, to them. Binoculars with an exit pupil larger than 5 mm are recommended.
Photographing the night sky (fixed-mount shooting)
By simply placing your camera onto a tripod, you will be able to impressively capture the twinkling stars in the night sky along with buildings or landscapes.
(Camera: Nikon digital SLR D5500 Lens: AF-S DX NIKKOR 18-55mm f/3.5-5.6G ED VR II)
Choose a shooting location while it is still light, and finish the set-up. Setting up your tripod and adjusting the camera settings only gets more difficult as it gets dark.
Take out your equipment (tripod, camera, lens with hood, and remote cord).
Roughly decide the height of your camera with your hands, and extend the tripod legs according to your planned composition.
Place the tripod on a solid surface. Make sure that the legs are fully open and stabilized.
Firmly fix the camera on the mount head, then attach to the tripod. Double check that they are tightly attached.
Attach the remote cord to the camera (not necessary if you use the Exposure Delay Mode or the Self-Timer.)
There are particular ways to setup the camera for astrophotography. We will show you the workflow employed to take the image illustrated. Use the following procedure and settings as reference for your first shoot.
Lens: AF-S DX NIKKOR 18-55mm f/3.5-5.6G ED VR II
Camera: Nikon digital SLR camera D5500
Image quality: 14-bit RAW (NEF)
• Exposure: [M] mode, 45 seconds, f/3.5
• High ISO NR/Long exposure NR: Low/On
• White balance: Auto
• Sensitivity: ISO 3200
Post-shoot image processing
Using a third-party image-processing software, white balance is adjusted to achieve neutral gray in the background. Contrast is enhanced with the tone curve so that the Milky Way is rendered with a feel of depth. Lastly, the saturation is slightly enhanced to give the stars more color.
Set the shooting mode to M (manual).
Set the monitor brightness to the dimmest position.
Set the image quality option to [NEF (RAW) + JPEG fine].
Set the Long exposure NR to [On], and the High ISO NR to [Low].
Note: By setting the Long exposure NR option to [On], the time required for processing the image roughly doubles, and another picture cannot be taken before processing is complete.
With the lens, select [M] (manual focus) for lens servo, and turn off the Vibration Reduction (VR).
Set the focal length to the 18 mm wide-end, by rotating the zoom ring.
Set the sensitivity to ISO 3200.
Set the aperture to f/3.5
Rotate the command dial to set a shutter speed at Bulb.
Adjust the focus.
To manually adjust the focus, rotate the focus ring on the lens barrel by hand. Let’s see how we can adjust the focus using live view.
Guide a bright star into the center of the live view screen (raise the ISO sensitivity if the star is not seen clearly).
Enlarge the view to the maximum to confirm the precise focus of the image of the star (image shows an out-of-focus image).
Rotate the focus ring while viewing the LCD monitor. The focus is set when the star looks its smallest, and brightest.
Fix the focus ring with adhesive tape to prevent it from moving during shooting.
• Due to the low-light situation, you could accidentally touch the focus ring while trying to adjust the composition, and lose the focus.
Note: If you change the zoom position after focusing, you’ll have to readjust it. Fix the focal length before adjusting the focus distance.
You could use a streetlight in the distance instead, if it is difficult to adjust focus with a star.
Set the self-timer options via the self-timer button if you plan to use this function.
Release the shutter.
Adjust the focus.
Confirm your shot on the LCD monitor. If the image looks too bright, you could lower the ISO, select a faster shutter speed, or stop down the aperture to reduce the exposure. Practice the opposite (i.e. raise the ISO, or increase the exposure) when the image is too dark.
Capturing star trails
We’ve now introduced fixed-mount shooting and photographing the stars as point images in short exposure times. What happens if you use a longer exposure? Here is a comparison between 30 seconds, then 5, 10 and 15 minutes. You see that we get longer star trails as the exposure time gets longer. This is due to the diurnal motion of the stars. ISO sensitivity should be set low. Try various exposure durations to create impressive star trail photography.