All you need to know about Comet Nishimura and what we can expect this month.
Comet Nishimura, or C/2023 P1 (Nishimura) to use its official designation, is currently visible in the morning sky in the constellation Cancer.
Will Nishimura become visible to the naked eye? That’s the question on every comet-chaser’s lips at the moment.
Time will tell. In this blog we’ll be following the progress of Comet Nishimura over the coming days and weeks.
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Remember how, just over two years ago, we were all gazing up wistfully at beautiful Comet NEOWISE shining in the summer sky?
With its long tail it was a lovely sight as it drifted beneath the Big Dipper, and was clearly visible to the naked eye.
Frustratingly, there have been no obvious naked eye comets since then – but that might be about to change…
Will Comet Nishimura be visible to the naked eye?
Comet Nishimura, if it follows predictions, might become visible to the naked eye after this weekend, when it moves into the evening sky.
It’s important to bear in mind that when it comes to comets ‘visible to the naked eye’ does not mean ‘will be a stunning sight to the naked eye”’
It just means that it might reach a magnitude high enough to be seen without help from binoculars or a telescope.
Possibly only as a smudge in the sky, possibly something a lot better.
We’ll have to wait and see what Comet P1 does.
There’s a chance the comet will ‘do an ISON’ and break apart as it rounds the Sun, but it’s showing no signs of doing that so far.
So comet observers are cautiously optimistic that more than just a cloud of debris will sweep up into the evening sky.
Comet P1 Nishimura‘s discovery
C/2023 P1 (Nishimura) is a long period comet that was discovered by Hideo Nishimura on 12 August 2023.
He was using a 200mm f/3 telephoto lens mounted on a Canon EOS 6D DSLR camera.
Calculations have since shown that Comet Nishimura has an orbital period of around 437 years.
The comet was in Gemini and shining at around 10th magnitude when it was discovered.
But it has been brightening steadily and is now in Cancer.
It’s around 6th magnitude, shining to the upper left of Venus in the pre-dawn sky.
P1 would probably be a naked eye object now if it wasn’t having to fight against both the bright morning twilight and the light of the Moon.
I’ve taken photos of it for the past two mornings, from the 800 year old ruins of Kendal Castle in Cumbria, UK.
My images taken using a DSLR camera, tracking the sky on a motorised mount, show it has grown a short but very pretty forked tail.
This tail would definitely look more impressive against a darker sky.
If you want to try it for yourself, read our guide on how to photograph a comet.
What can we expect from the comet?
Comet P1 Nishimura will reach its closest point to Earth on 12 September 2023 and its closest point to the Sun on 17 September 2023.
At this point it will have moved up into the evening sky. And what might we see then?
If you remember, Comet NEOWISE was a lovely sight because it was high in a dark sky.
Comet P1 will not be. It will remain firmly embedded in the evening twilight, always low in the sky, until it fades away.
Calculations suggest that it might reach a maximum magnitude of 2.
Which of course would make it obvious in a darker sky.
But low in the twilight it will appear fainter than that, perhaps merely a smudgy star in binoculars.
However, if the tail it is growing now continues to grow it might make the comet more obvious.
And it may yet surprise us with an impressive tail, pointing up from the horizon, beneath the curved handle of the Big Dipper and Arcturus.
The bottom line is we just don’t know what’s going to happen.
Cross your fingers that it brightens as hoped, but disregard any social media predictions of P1 becoming a “dazzling sight” or “lighting up the sky”.
How to see Comet Nishimura for yourself
In the meantime, if you want to see Comet Nishimura now you’ll need to be getting up early, around 4am.
Train your binoculars, cameras and telescopes to the north-east, where P1 is waiting for you.
It’s not far from Venus, heading for its close encounter with the Sun.
Good luck!
We’ll update this blog over the coming weeks as things develop.
Have you observed or photographed Comet P1 Nishimura? Let us know by emailing contactus@skyatnightmagazine.com