Human Interest

NASA is calling tonight’s full moon a supermoon. Not everyone agrees, but it is a great opportunity to catch a lovely photo.

Over the past two years, Angel Lopez-Sanchez has been photographing the Moon with his son Luke.
Tonight, they may finally get an image of a full moon, one of a handful they still need to document the Moon in all its phases.
Luke is helping his dad take photos of the Moon.(Supplied: Ángel López-Sánchez)
“It’s a beautiful project to do with kids from home,” says Dr Lopez-Sanchez, an astrophysicist at Australian Astronomical Optics, Macquarie University who is also known for his astrophotography.
Luke was five when they started the project together.
“He has always been interested in stars and astronomy. I don’t know why,” Dr Lopez-Sanchez laughs.
Not only is it a full moon, but according to NASA, it’s the fourth “supermoon” of the year, aka a “Super Flower Moon”.
A supermoon which is a term that was first coined by an astrologer (yes, we do mean astrologer) happens when the full moon falls near the point at which the Moon is closest to Earth.
Not everyone agrees that this month’s full moon is a supermoon, but it is a great opportunity to catch a lovely photo.
And, unlike the other astronomical events in the sky this week such as a meteor shower and comet, the full Moon is easy to find and it comes up in the evening.
Is it really a supermoon?
This looks like a supermoon. But it’s an illusion.(Getty Image: Joel Sharpe)
It’s hard to work out the exact moment when the Moon is fully lit up just by looking at it.
But in astronomical terms, a full Moon occurs at a specific time when it is exactly opposite or at syzygy with the Sun.
This month, syzygy happens to be at8.45 PM (AEST) on May 7.
Each month there is also a specific point in time when the Moon is closest to Earth, known as perigee. This month, the perigee was yesterday at1.03 PM (AEST).
NASA say a supermoon is a full Moon that iscloser than 367,607 kilometres to Earth near perigee. If we use this definition, this is the fourth supermoon this year; the others were in February (Super Snow), March (Super Worm) and April (Super Pink).
Yesterday at perigee the Moon was 359,654 kilometres away. By the time it gets to the full Moon tonight, it will be 361,159 kilometres away.
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But others say it’s not a “supermoon” because the perigee didn’t happen within 24 hours of the full moon. If we use this definition, we’ve only had two supermoons this year in March, and in April, which was closer to Earth than this month’s full moon.
In reality, whatever definition is used, it is virtually impossible to tell the difference between a supermoon and a regular full moon with the naked eye, Dr Lopez-Sanchez says.
“The difference between a standard moon and a supermoon might be only 4-5 per cent,” he says.
“You can distinguish the difference if you take a photo and compare the sizes but with our naked eye it is very difficult.”
It’s a nice excuse to look at the sky
Even though a supermoon is more hype than reality many of the photos you may see are taken using a telephoto lens or telescope or near the horizon to make the Moon look bigger it’s still a good excuse to look at the sky.
“It’s the perfect opportunity to take photos if the weather is good,” Dr Lopez-Sanchez says.
When it is a full moon, the Sun directly lights up the face of the Moon, so you can see all of the volcanic plains or seas and ocean (grey patches) and plateaus (white areas).
It’s also the best time to photograph finer features such as rays coming from craters such as Copernicus in the Ocean of Storms, the large grey patch on the right side of the Moon as seen from Australia, Dr Lopez-Sanchez says.
“These are ejections when asteroids collided with the Moon and created the crater,” he explains.
“You can only see that during full moon because these structures are relatively thin and not very big and the only way you see them is when the Moon is just up.”
The Moon looks spectacular at other times of the month as well.(Supplied: Luke and Ángel López-Sánchez)
But if you don’t go out tonight, or the weather blocks your view, the beauty of the Moon is that it is in the sky most nights of the month.
Dr Lopez-Sanchez’s favourite time to photograph the Moon is when it’s in its first quarter phase, when the Sun illuminates the Moon from an angle so you can see the details of craters in shadow.
“If you see the Moon at the beginning of the night and just four or five hours later you will notice the difference, the shadows have moved because the Moon rotates,” he says.
Photographing the Moon
If you want to be creative you can take advantage of the Moon illusion, which makes everything on the horizon look bigger, to frame your shot.
“We don’t need the supermoon to [make the Moon look big]. Many of us have observed the full moon rising over the ocean and it seems magnificent and very big because our brain is tricking us,” Dr Lopez-Sanchez says.
He took the image of the Moon above the Sydney skyline at the top of this page using a 70-200mm f2/8 zoom lens at 85mm, but with different exposition times for the Moon and for the foreground.
“Otherwise it is impossible to get at the same time the Moon and the foreground, as the Moon would be very overexposed,” he explains.
Luke is working with his dad to capture every phase of the Moon.(Supplied: Luke and Ángel López-Sánchez)
At home, Luke and his dad take close-ups of the Moon using a digital camera attached to a telescope to magnify the features on the Moon.
Luke points the telescope at the Moon and takes the photos, which are then processed using software by Dr Lopez-Sanchez to stack them up, align, sharpen and colour balance them.
“We have around 20 good photos of the Moon in different phases in total,” he says.
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While they use a camera attached to a telescope to zoom into the Moon, you’ll still get a reasonable image without a telescope using a 150-200 mm lens, he says.
“Using a standard lens or a mobile camera you will not have much resolution but still it will be a nice photo and you will see the differences and changes of the shadows and some structures day after day,” Dr Lopez-Sanchez says.
Other tips include:

  • Use a tripod and a cable to avoid vibration
  • Reduce the ISO as low as you can
  • Decrease aperture (f number) f15-f25
  • Use a short exposure to reduce the light 1/1000-1/200 seconds
  • The combination of low ISO, large f number and exposition time has to provide an image that is not overexposed or underexposed. “That depends a lot on your camera.”
  • Focusing can be tricky so use a bright star to focus. “I’ve tried to do it just focusing on the Moon, but I have found sometimes it is a bit tricky.”
  • Don’t take just one image, take hundreds of images then combine them using software to give you a better quality image

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