Comet C/2022 E3 (ZTF) is visible in the sky above the Mojave National Preserve in San Bernadino County as it approaches Earth for the first time in about 50,000 years on January 31, 2023 near Baker, California. Photo: Ethan Miller / Getty Images via AFP
A green comet that was last seen roughly 50,000 years ago has appeared in the skies this week, including in Australia and New Zealand.
Also known as Comet C/2022 E3 (ZTF), its debut in the night sky was discovered by astronomers in early 2022, using a wide-field survey camera at an observatory in California.
But on 2 February, it caught the attention of astrophotographers and space enthusiasts alike.
Because that was when the comet was closest to Earth - about 41.8 million kilometres away - in a very long time.
Although it is not uncommon for comets to make rare appearances in the sky due to the size of their orbits, the green comet was last seen roughly 50,000 years ago.
The sheer distance means the comet, despite measuring one-kilometre wide, might only be slightly visible to the naked eye.
Light pollution also affects visibility so its natural green glow can only be picked up by astrophotography.
That is why star-searchers have joined the chase to capture the phenomenon - jumping on the opportunity to put their cool gadgets to use and flex their sky imaging skills.
Here are some impressive takes from all around the world, starting with...
Australia
A stunning sight of the green comet seemingly headed towards Mars surrounded by a blanket of stars caught just outside of Ballarat, Victoria.
The United Kingdom
This London-based photographer was lucky enough to capture a "faint hint" of the comet's tail as even the brightness of the moon can impact the quality of imagery.
Comet C/2022 E3 ZTF, last seen in this neighbourhood c50,000 yrs ago.
— Nick Williams ✈️ (@Nick_E4Astro) February 4, 2023
Despite the bright moon when these were taken, there's a faint hint of the tail at the 2pm position in the 1st image ☄️#astrophotography pic.twitter.com/3o3t7TzKMy
India
The comet stands out against a backdrop of light strokes in the night sky, captured using a DSLR camera.
Germany
The green glow coats a white globe as it emits a light orange tint on the other side, shining on to the neighbouring stars.
Astrophoto: ##Comet C/2022 E3 (ZTF) - 01/23 - https://t.co/e86m0Vl9vY - I used a short clear time frame in the morging hours to capture ##Comet C/2022 E3 (ZTF). #CometC2022E3ZTF #Astronomy #Astrophotography #ClearSkies #SolarSystem #Space pic.twitter.com/AM4bAGbDj9
— Thomas Hanrath (@AstrographyEU) February 3, 2023
The United States
The comet and its hues of green is on full display when at its brightest and closest to Earth.
The comet's notable streak appears when long exposure is done using a camera where the shutter speed is dragged out.
Astrophoto: ##Comet C/2022 E3 (ZTF) - 01/23 - https://t.co/e86m0Vl9vY - I used a short clear time frame in the morging hours to capture ##Comet C/2022 E3 (ZTF). #CometC2022E3ZTF #Astronomy #Astrophotography #ClearSkies #SolarSystem #Space pic.twitter.com/AM4bAGbDj9
— Thomas Hanrath (@AstrographyEU) February 3, 2023
Spain
A green comet named Comet C/2022 E3 (ZTF), which last passed our planet about 50,000 years ago, is seen from the Pico de las Nieves, on the island of Gran Canaria, Spain. More photos of the day: https://t.co/f1tocBaCIz @borjasuarez_gc pic.twitter.com/eAuXNdLnC5
— Reuters Pictures (@reuterspictures) February 1, 2023
Why do photos of the green comet all look so different?
UQ astrophysicist Ben Pope says, "Nearly everything in astronomy is basically white to the naked eye except, like, red giant stars and Mars appears a little red, Jupiter is quite noticeably yellow".
So the colours seen in photos are a result of staging, imaging and editing.
Whether they are true to the real deal, it's all up to interpretation.
US photographer Andrew McCarthy revealed a raw black-and-white image of the comet in contrast to his processed photo, addressing the controversy in astrophotography.
A great example is this recent image of the comet. In the thread I stated how processed it was due to being captured through haze (as well as including my raws), but peers called the image misleading as a result, despite my efforts in transparency and to stay true to the data. pic.twitter.com/uqL65TXQs6
— Andrew McCarthy (@AJamesMcCarthy) February 7, 2023
Another US photographer was not shy to detail the extent of their process in transforming the raw image to the end product, sharing the tools used and the time taken.
-ABC
