What is a total lunar eclipse and how can you capture it on your smartphone?

Total lunar eclipses provide a great opportunity to share in the wonders of our Solar System. Let’s talk about the science behind this phenomenon and how you can capture a stunning shot with just your smartphone.

Total lunar eclipse (red moon) in black sky

A total lunar eclipse seen from Uluṟu-Kata Tjuṯa National Park by Melanie Dretvic/Unsplash.

What is a total lunar eclipse?

A lunar eclipse only occurs during a full Moon and when the Sun, Earth and Moon are aligned. During a lunar eclipse our Earth comes between the Sun and the Moon, blocking sunlight from directly reaching the Moon and casting a shadow across its surface. The time when the Moon is completely in Earth’s shadow is called ‘totality’.

This is also commonly known as a ‘blood Moon’, a name that refers to the reddish colour of the Moon while it’s in Earth’s shadow.

Why does the Moon look red during a lunar eclipse?

A full Moon is usually lit up by sunlight and as a result, you see a bright, large Moon in the sky.

During a total lunar eclipse the Moon moves through the darkest part of the Earth’s shadow. The only light that can reach the Moon passes first through Earth’s atmosphere, which acts like a filter. The atmosphere scatters blue light and only lets the red and orange light reach the Moon’s surface, giving the Moon a reddish appearance during a lunar eclipse.

Infographic of total lunar eclipse

This is how the Sun, our Earth and the Moon line up during a total lunar eclipse. The full Moon passes through the darkest part of the Earth’s shadow.

What should we look for?

One of our astronomers, Dr Vanessa Moss, says we should look for a gradient of colour across the surface of the Moon as the eclipse progresses.

For the best view, Vanessa suggests you find a place that is dark and away from light pollution, but you can still see the eclipse in big cities without any special equipment, provided there isn’t cloud covering the Moon.

“This is an opportunity to get your friends and family together and go outside to look up at this natural phenomenon,” Vanessa said.

How can I capture the total lunar eclipse using my phone?

You don’t have to be a professional photographer to get a great picture. Photographer Alex Cherney won the 2020 David Malin Award for Smartphone Astrophotography. He says you’ll need a tripod with an adapter for your smartphone. You’ll also need to practice before the eclipse to get a good picture.

Here is what he recommends:

Night vision

On your smartphone, set the display brightness to dim so it doesn’t ruin your night vision. Additionally, make sure that your flash is turned off. Then set your smartphone timer to 2-3 seconds to minimise any camera shake.

Zoom in

If your smartphone is equipped with an optical zoom lens, it will help to make the Moon look bigger in your picture. But, using digital zoom doesn’t work very well in low light. So only zoom in enough that you don’t lose the quality of your image.

Focus far

Practice during the day or night using manual focus. Focus your smartphone on an object in the distance and make it as clear as possible. Most Android phones can be switched to Pro mode with manual focus and exposure controls, but iPhones will need a third-party camera app such as Camera+ 2 or Halide.

total lunar eclipse in night sky

Here’s an example of what a 5-10-second-long exposure of the total lunar eclipse taken with a smartphone, equipped with a 5x-10x optical zoom lens on a tripod may look like. Image: Alex Cherney.

Long exposure

Keep in mind that the Moon will get red and very dim during the eclipse, so you’ll need a couple of seconds of long exposure with your smartphone on a tripod. Again, practice before the eclipse and learn how to adjust the image brightness or exposure. It’s important if you want to take a good photograph.

You may also want to try using night mode if you have an iPhone 11 or later model, or night sight/night mode on Google Pixel 5 and Samsung S20 or S21.


If you’re away from the city lights, you can use night mode time-lapse on an iPhone 12. This will really showcase the effects of the Earth’s shadow in motion.

Have fun

Don’t forget to take some time to enjoy the view! Remember to share your photos on Instagram with #CSIRO in the caption so we can see your snaps!


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