Every so often, the universe treats us to amazing astronomical events such as meteor storms, comets and lunar eclipses. But the most spectacular of all, that can stop people in their tracks is a solar eclipse. This rare event occurs when the Moon passes between the Sun and the Earth, covering the Sun's disk and casting its shadow upon our planet.
You don't have to be an avid astronomer or an astrophotography enthusiast to enjoy witnessing or photographing a solar eclipse. There are various methods to observe and capture this phenomenon using a range of equipment like dedicated astro cameras, DSLRs, solar glasses, or handmade solar projectors.
What is a solar eclipse?
A solar eclipse occurs when the Moon, in its orbit around the Earth, aligns precisely between the Earth and the Sun. This obscures the Sun partially or completely from view.
There are four main types of solar eclipses:
Total - this occurs when the Moon completely covers the Sun, as seen from Earth. Observers in the path of totality can see the Sun’s corona.
Annular - when the Moon is too far from Earth to completely cover the Sun, leaving a “ring of fire” or annulus around the Moon.
Partial - when the Moon partially covers the Sun, resulting in a crescent-shaped Sun.
Hybrid:- a rare type that shifts between a total and an annular eclipse along its path.
Safety first - protect your eyes and equipment
Observing a solar eclipse through photography or direct viewing requires caution to prevent eye damage and protect your equipment. Staring directly at the Sun can cause permanent eye injury.
How to watch a solar eclipse
Handmade pinhole projectors
A simple and safe way to view a solar eclipse is by creating a pinhole projector. To make one, you will need two pieces of stiff white cardboard or two paper plates. Firstly, make a tiny hole in the middle of one piece using a pin or thumbtack.
Ensure that the hole is round and smooth. Then, with your back towards the Sun, hold the piece with the hole above your shoulder, allowing the Sun to shine on it.
The second piece will act as a screen. Hold it at a distance, and you will see an inverted image of the Sun projected on it through the pinhole.
Solar eclipse glasses
Solar glasses are a popular method for viewing a solar eclipse. They have an optical density of 5. This allows them to block 100% of harmful ultraviolet and infrared light and 99% of visible light so that you can observe the eclipse safely. In most cases, the Sun will appear as a white or pale yellow disk.
Ensure that the glasses meet the international standard of safety (ISO 12312–2 or ISO 12312–2:2015). This standard ensures that the glasses are thousands of times darker than standard sunglasses. You shouldn't use solar eclipse glasses with cameras, binoculars, or telescopes. These devices require different types of solar filters.
Telescope or binoculars
Telescopes or binoculars must be equipped with specialised solar filters designed for solar viewing. These filters fit over the aperture of the telescope or binoculars.
You can make your own solar filter using solar film with an optical density of 5 and a filter holder made of cardboard, or you can 3D print one. One of the most popular and affordable types of solar film brands is Mylar. While Mylar provides a safe view of the Sun, the image quality might not be as high as other types of filters. Mylar is biaxially stretched during its production, which can cause a band of scattered light across the image and a brighter background.
The best film for solar observation is the Baader AstroSolar film. Baader film provides a neutral cool-white image. This allows the use of additional filters if required. It is not stretched, so you get much less scattered light and a very dark and high-contrast background.
A more expensive option would be a hydrogen-alpha solar telescope, such as the Coronado PST.
Optical projection
If you have binoculars or a telescope but don't have any solar film, you can view an eclipse using optical projection. Optical projection is a method that involves using optics, such as lenses and/or mirrors, to project an image of the Sun onto a surface for convenient viewing.
To set up your optical projector you need to first point the telescope or binoculars at the Sun. Do NOT look through the telescope or binoculars while you are doing this. Instead, align them with the Sun by looking at the shadow of the device. When the device is pointing directly at the Sun, the shadow will be smallest.
Once your device is pointing at the Sun, hold a piece of white paper a few inches away from the eyepiece. An image of the Sun will be projected onto the paper. You can adjust the focus of the device until the image is sharp. You can fit the telescope with a shade collar made of cardboard.
Remember, passing bright sunlight through binoculars or a telescope can damage the device, and there’s a danger that someone might look at the Sun through the device and injure their eyes. You should NOT attempt optical projection unless you:
are an experienced astronomical observer
are using your own equipment
can remain with your equipment at all times to supervise its use.
How to photograph a solar eclipse
For solar photography, a DSLR or a dedicated astro camera paired with a telescope or a long lens, preferably 200 millimetres or more for intimate views is ideal. Wide-angle or prime lenses are best for capturing the eclipse if you want to include a scenic backdrop.
While photographing, it is important to protect your camera and your eyesight. You can craft a DIY solar filter using Baader OD 3.8 Solarfilm and a holder fashioned from 3D printing or cardboard. Alternatively, opt for a robust, commercially available solar filter that fits the thread of your lens or telescope’s front element.
Solarfilm allows you to photograph the Sun’s photosphere and sunspots, while a specialised hydrogen-alpha (H-Alpha) filter is needed to reveal the Sun's chromosphere, flares and prominences. These filters are not the same as deep sky H-Alpha filters.
During totality, it is safe to remove your solar filter. This will allow you to capture the solar eclipse in broadband light. It is the only time the Sun's corona can be viewed and photographed.
If you're using an astro camera, lucky imaging can give you sharper more detailed results. Lucky imaging is a technique used in astrophotography to capture high-resolution images of celestial objects through the Earth’s turbulent atmosphere. It involves taking a large number of short-exposure images or video and then selecting only the sharpest images or video frames for stacking and combining into a single high-quality image.
Tips for getting the perfect shot
Before the eclipse begins, ensure your camera equipment is fully charged.
Attach a solar filter to your camera lens to protect the sensor from the sun's intense light.
Adjust your camera settings to achieve the correct exposure for photographing the sun during the eclipse. Start with a low ISO setting, for example, ISO 100, and a small aperture such as f/8 to f/16 and a fast shutter speed to avoid overexposure. Use the camera's histogram to monitor exposure levels and make adjustments as needed.
Experiment with different focal lengths to capture the eclipse at various stages, from partial to totality (if applicable). Consider including foreground elements such as landscapes or silhouettes to add context and scale to your images.
Try bracketting. This allows you to blend different exposures.
Plan your shots in advance based on the eclipse's duration and progression. You can use a solar tracking app or website to determine the eclipse's start, peak, and end times for your location.
Be ready to capture key moments, such as the diamond ring effect during totality or the crescent Sun during partial phases.
Whether you’re taking photos or just watching, remember to stay safe. Plan your photos, enjoy the moment, and you’ll have great memories to last a lifetime.
For a comprehensive list of upcoming solar eclipses based on your location, refer to timeanddate.com.
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