Astrophotography is a higher art that requires discipline and the utmost dedication. How many times have you come across a photo of the Milky Way or the moon and wondered in awe how they managed to capture it?
The answer to that is a disciplined approach to astrophotography and very deep understanding of the camera and how it works to capture frames.
With this article, we hope to introduce you to the steps and techniques that you would have to master to capture something as scintillating as published on the magazines.
And although it is beyond the scope of this article to go in depth about camera mechanics, we would discuss optics too for you to get a holistic understanding of how astrophotographs come to be.
Table of Contents
Creating star trails
North Star Trails – Time lapse in HD.
Video by Jamie E
Star trail photos are made up of hundreds (sometimes even thousands) of images taken across the course of a night. This tutorial will cover the shooting and editing process from start to finish.
One small error can render eight hours of shooting worthless, so hopefully this tutorial will help you to avoid any such errors.
The process for shooting a star trail image starts with shooting a single image during twilight to capture the shadow details in the foreground under the softest light possible.
When the sky is completely dark we can start the process of shooting the hundreds of individual frames that will be later combined to create the star trails.
Once the shooting is complete we’ll move onto editing in Photoshop to combine all the star images together.
We’ll then combine the result with the single image shot during twilight, using the best parts of each image.
You’ll need:
DSLR camera with battery grip. Find our review for the BEST CAMERAS FOR UNDER $300.
Wide-angle lens. Check out our budget Camera Lens review for under $200 here.
Stable tripod and head. Find our review for Best Budget Tripods Under $150 here.
Programmable shutter release. Find it on Amazon here.
Powered dew heater or chemical warmer sachets. Find the latest price on Amazon here.
Photoshop. Find the latest price on Amazon here.
Large memory card. Find the latest price on Amazon here
Steps:
PLAN.
Scout the location before the shoot. Learn where the celestial pole will be and work out your composition – if you aim in the wrong direction you can’t correct it later.
Check on the Moon phase and path across the sky – a new Moon is best. Use The PhotoPills app to plan as it has an augmented reality mode.
FOCUS.
Set the focus so that all foreground elements are sharp, not on the stars themselves. Stars that are slightly out of focus will result in smoother and slightly thicker trails.
Do not adjust focus during the shoot or it will cause problems in the editing stage.
DLSR Camera focus tips.
Video by steeletraining
SHOOT THE FOREGROUND.
Shoot the foreground after sunset so it’s evenly illuminated by soft light. ND or graduated ND filters can be used if needed, but be careful not to move the camera when removing any filters.
Use a small aperture for depth of field. Set the camera to its base ISO to maximize dynamic range and image quality.
PROGRAM THE REMOTE RELEASE.
Make sure the camera is set to Bulb mode.
Set the remote shutter release to take 40-second images with the shortest possible interval. For most remotes this will be one second, though there are some that can do 0.1-second intervals.
CAMERA SETTINGS.
Make sure long-exposure noise reduction is switched off in the camera menu. We recommend settings of 40 seconds, at f3.5, ISO 800. Shoot RAW (14-bit lossless if possible), White Balance set to Sunlight.
If shooting under a Moon that is between 1/4 and 1/2 illuminated, drop the ISO to 400.
SHOOT THE TRAILS.
When the sunset afterglow has faded and the stars are visible we can begin shooting the trails. Make sure you know the run times of all your batteries. The lens heater will usually require one or two battery changes during the shoot, as batteries will be depleted faster in colder weather.
Editing steps:
CHOOSE STACKING SOFTWARE.
There are a few different programs that can be used for stacking. Using RAW files in Photoshop is best.
STACK IN PHOTOSHOP.
Load the images into a stack. You can remove any unwanted trails by painting over them with a black brush. When the images are clean use the Lighten blend mode, flatten and save as a 16-bit TIFF.
When you’re done load all the stacked images into a stack and repeat.
BLEND.
Load the final stacked star image and the twilight foreground into layers.
Create a Contrast mask to blend in the foreground elements from the twilight image, replacing the silhouetted foreground elements from the stacked star shots.
Blending your spiral star trails with photoshop.
Video by Milky Way Mike
ENHANCE.
Use the Contrast mask to apply Exposure/Levels/Curves adjustments to the two individual layers. Bring out the colours by pushing the Saturation and Vibrance sliders up.
Shooting the Milky Way.
A huge amount of planning is required before you can attempt to shoot the Milky Way.
You should start by checking the weather forecast to make sure that the skies are clear with no moon between the months of April and September when the Milky Way is visible in the Northern hemisphere.
The other issue is light pollution, which can blot out large portions of the Milky Way and other stellar formations.
Having found a dark spot, you want a good foreground: a good shot needs an earthbound anchor such as abandoned buildings, trees or water.
Steps:
SET UP.
Get on site in plenty of time, with a head torch, warm clothes and a sturdy tripod with cable release. As dusk deepens, start working out your shot composition.
The sky is your priority, but here, the rocks gave us a good start on the rule of thirds principle.
As astronomical twilight ends, you should just be able to make out the Milky Way as a faint diagonal, leading leftwards up the skyfrom the compass reference Sky Guide hasgiven you.
To capture it, you need a camerawith a good high-ISO capability and a very wide-angle lens.
Focusing is a major issue, but theheadtorch can be used to light a physical object like a rock and focus on that. You can use Live View to manually focus. On some lenses infinity is perfect.
TAKE A SHOT.
As the dusk fades, take test shots using the 500 rule, dividing 500 by the focal length of your lens (include your crop factor of 1.5 or 1.6 if shooting APS-C).
The Sigma lens is the world’s fastest 14mm lens, and when I tried it, my aim was to shoot at f/1.8 and keep my ISO down.
We’d normally shoot the Milky Way between ISO 4000 and 6400, but we were getting clean results at ISO 2000. What we wanted to make sure of was that we had a perfect diagonal as a leading line away from the rocks.
You can light-paint your foreground or have it as a silhouette; in our case, though, the late dusk light lit the rocks.
DO INITIAL ADJUSTMENTS.
With Milky Way shoots, the RAW file is only ever the starting point.
The human eye is limited in what it can see at night, but your full-frame sensor has a much better dynamic range.The RAW file looks dull and flat, as it should.
First, do some overall adjustments in Lightroom. Use Exposure to push your histogram to the right, and add some Contrast. Bring Shadows up to work on your foreground and add an S-shaped Tone Curve to pop the contrast.
The Milky Way is still quite pale – but don’t worry!
OPEN IN PHOTOSHOP.
The photo is now coming together, so it’s a good time to add in some Photoshop extras. With your edited image exported and open in Photoshop, add a new layer then go to Filters >Sharpen >Unsharp Mask.
If you want to, add a layer mask and erase the mask over your foreground. The aim is to make the stars pop. You can run the Unsharp Mask again for extra impact.
Make a lunar analemma.
The solar Analemma over Edmonton.
Video made by Luca
An analemma is a composite picture of usually the Sun, taken over the period of a year, which shows its shifting position in the sky as the seasons progress. It can take a year to create a picture like this, so as you can imagine, it takes some dedication.
However, you can create the same effect with the Moon in just 29.5 days, if you’re lucky enough to have a month of clear night skies!
The image gives you an extended figure of eight pattern and can make a very attractive picture.
As with the Sun, an analemmaonly exists as an abstract idea and as a compilation of images within one photograph, and this is the only way to see it.
The trick to creating a lunar analemma is to understand that the Moon returns to the same position in the night sky around 51 minutes later each day.
Therefore, if you image the Moon around 51 minutes later each successive day over the course of one lunar month or 29.5 days, it will trace out the figure of eight curves when the images are combined.
This pattern is due to its elliptical orbit and its tilt.
You’ll need a good, sturdy tripod and a way of marking its position so that you can put it in the exact same spot each day.
You’ll also need some image processing software and a little skill in its use to get a good final image, especially as the thin crescent phases will need to be taken in daylight, or at least bright twilight.
Use the wide-angle lens for the background shot and to get the positions of the Moon in each phase, as this will be the image upon which you will build your composite.
An attractive building or mountain range can look good for the background, but remember to leave plenty of room in the sky in which to superimpose your lunar images.
The telephoto lens is used to get more detailed images of the Moon. During image processing these shots will be superimposed onto the background in exactly the right spots.
If you don’t get a whole month of clear skies, you can always take a shot of the correct phase the following month and work that into your final image. Bearing this in mind, it may still take some time to build up your final analemma, but it will be worth it.
Building the composite.
Use a wide-angle lens for the background and Moon position shots and then swap to the telephoto lens or ‘zoom in’ and take some more detailed images of the Moon.
You’ll use your image processing software to superimpose these details onto the position of the Moon in your wide-angle image later on. The reason for this is to make the Moon look more real.
In the wide-angle shots it will seem very small and insignificant. You’ll also need to vary the length of exposure to cope with the differing light conditions.
Take a few images in various settings to increase your chances of getting a good shot each day.
Steps:
TAKE A BACKGROUND IMAGE.
Choose a good location and background for your image and take some well-composed shots. Be sure to leave plenty of sky in the images, as this will be filled with your analemmaover time.
KEEP TRACK OF THE TIME.
Keep an observation diary of the exact time of your first shot and note down the phase of the Moon each night. This will help keep track of your shots and assist while creating the composite later on.
EXPERIMENT WITH YOUR SETTINGS.
Take multiple images each night and vary the settings of the exposure time and ISO each time you photograph the Moon. This will ensure you get at least one good shot per night for your analemma.
ADJUST YOUR VIEWING TIME EACH DAY.
Don’t forget to add 51 minutes to the time of viewing for every successive day that you photograph the Moon during the lunar month. Your observation diary will help with keeping track of this.
GET MORE DETAIL.
Use a telephoto or zoom lens to get more detailed images of the Moon. These details will be superimposed onto the position of the Moon in your wide-angle shot later on. Don’t make the lunar disc too large though.
EDIT YOUR IMAGES.
Once you’ve got all of your shots across the lunar month and selected the best ones, combine all of the images into a composite using computer software such as Photoshop. This will show up the analemma.
Related questions.
What settings are preferable for astrophotography?
The best practice is to experiment with different lenses and accessories until you find a combination that works for you. It is generally suggested to use an aperture that is between F/2.8 to F/4 and shoot in manual mode.
You should also change your white balance settings to daylight and shoot in RAW image format for best results. Change the ISO from 400 to 1600 based on the weather conditions and the target you’re shooting.