Stargazers keen to capture a rare "blood supermoon" tonight should allow plenty of time for preparation - and not bother with their phone camera, an expert says.
For about 14 minutes from 11.11pm on Wednesday, the moon's closest point of orbit with the Earth is due to coincide with total lunar eclipse - making for the first blood supermoon since 1982.
Here is the cloud forecast across Aotearoa in anticipation for tonight's #SuperBloodMoon 🌑🔴
— MetService (@MetService) May 25, 2021
Many areas have a good chance of seeing the moon!
Gisborne and Hawke's Bay look mostly cloud in an onshore flow.
Wairarapa, Fiordland and eastern Northland will be partly cloudy. ^Ash pic.twitter.com/Qa0wxpXO3z
Last night, MetService explained where in New Zealand Kiwi stargazers are most likely to get a good look at the rare astronomical spectacle.
Using a three-tiered system, they revealed how cloud cover would affect the viewing experience.
Current forecasting has Gisborne and Napier in the worst position, with cloud cover likely to block the view of the spectacle.
West is best in the rest of the North Island, with Palmerston North, New Plymouth and Hamilton in the box seat and everyone else having to deal with some cloud cover, including Auckland.
#SuperBloodMoon is happening on Wednesday night - which parts of NZ will be able to catch a nice glimpse? Angus has the cloud cover forecast 🌑🔴 ^AH pic.twitter.com/C5fzE8RqJJ
— MetService (@MetService) May 25, 2021
But the South Island is the place to be, with most areas free of clouds and set to enjoy the show, including Christchurch and Dunedin.
While the actual period of "totality" - when the Earth lines up between the Moon and the Sun and blocks out the Sun's light - will be relatively brief, the eclipse process itself is due to last five hours, beginning at 8.47pm.
Meanwhile, Stardome astronomy educator and astro-photographer Josh Kirkley has offered tips on how to get the best shot of the spectacle.
"Look for clear unobstructed night sky views. The blood supermoon will be visible high in our sky so you should be able to find a good spot wherever you are in New Zealand," Kirkley said.
"When the Moon goes into Earth's shadow - at just before 9pm - the reddish light passing through Earth's atmosphere will be refracted on to the Moon, creating a blood-red colour across the lunar surface."
The setting moon 🌕.
— NIWA Weather (@NiwaWeather) May 25, 2021
The moon will rise again just after 5:00 pm today, with #LunarEclipse2021, or blood supermoon, beginning at 11:11 pm today.
Can't wait. pic.twitter.com/AoJVV6P0Wl
Kirkley said anyone who wanted real photos would need a DSLR or mirrorless camera, with interchangeable lenses.
"Phone cameras just won't cut it for a nice clear shot," he said.
"Many standard cameras come with 18-50mm lenses, but I'd recommend lenses closer to the 300-600mm mark to get crisp close-up shots of the Moon."
The higher the number, he said, the better.
"Ideally, you'll also need a tripod, as night photography with handheld cameras will inevitably end up blurry."
Next, moon-shooters needed to ensure their settings were sorted before the big moment.
"To focus on the Moon, first you must turn off AF which is auto-focus," he said.
"This is a physical button on most lens bodies, and it must be changed to MF or manual focus so you can properly focus on the Moon.
"From here, you typically turn the ring around the end of a lens to focus on the object."
Once the moon was in clear focus, the next step was to ensure the aperture of the camera lens was as wide as possible.
"This is known as f-stop, and it basically means how much light your lens will let into the sensor," Kirkley said.
"The lowest possible aperture number for your lens will be best, as it allows you to take faster photos that capture more light."
An ideal f-stop would be around the f/2 mark.
"From here you will need a fast shutter speed," he said.
"Typically, you'd want long exposures to take photos of stars and the galaxy, but in this case the Moon is bright and it will be moving across the sky, so a faster speed will reduce blur from movement and over-exposure."
When it came to shutter speed, he suggested 1/100 would be a good starting point.
"The last setting is ISO. ISO is how 'sensitive' your sensor will be when it lets in light," he explained.
"ISO 400-800 would be a good start. This is the setting to play around with the most to get your ideal photo.
"If your photo is too bright and overexposed, use a lower ISO. If it looks too dim and grainy, move the ISO up until you have the desired results.
"There is no perfect setting to take a photo of the lunar eclipse but start with these basics and go from there."
Lastly, photographers needed to find a great vantage point.
"There's not a lot of time to get your perfect shot. Since the Moon is only going to just about enter, then quickly exit, Earth's central shadow, the coloured 'totality' of the eclipse will last only 14 minutes and 30 seconds and will start at about 11.11pm," he said.
"It's a good idea to practise and prepare your manual settings in advance. A combination of lens size, aperture, ISO and speed will get you the best results. Good luck."