Ladies and gentlemen, we have a new guest stopping for a bit to say hi! It’s Comet Nishimura, and it’s pretty much a big surprise to the entire astronomy community if you’ve been listing to all the buzz out there lately.
Below, we’ll share everything we know about it at the time of this writing (August 29, 2023), so you can become better informed and enjoy it while stargazing.
So, let’s dive in and learn how to see the new Comet Nishimura.
What is Comet Nishimura?
Comet Nishimura is a new comet that was discovered by amateur astronomer Hideo Nishimura on August 11, 2023. The comet is named after its discoverer, who spotted it using a 200-mm f/3 telephoto lens mounted on a Canon EOS 6D camera. The comet was hiding in the sun’s glare before Nishimura detected it. We’re sure glad he found it, because now we added another stargazing RV trip to our list this September!
According to NASA/JPL, this rare visitor to the inner part of our solar system has a 520 year orbit. This means that based on recent data, the comet is actually not interstellar but a local comet. However, more observations are needed to truly confirm the path, so stay tuned (we bet they’re right though).
| Comet Nishimura Facts | Interesting Details |
|---|---|
| When was it discovered? | August 12, 2023 |
| Who discovered it? | Hideo Nishimura, a Japanese amateur astronomer |
| How bright is it right now? | +7.8 magnitude, which means it is visible with binoculars or a small telescope |
| What kind of orbit does it have? | Local orbit for a comet, which means it orbits the Sun in our solar system |
| When will it be closest to Earth? | September 12, 2023 at 77.9 million miles (125.3 million km), which is about half the distance between Earth and Mars |
| When will it be closest to Sun? | September 17, 2023 at 20.92 million miles (33.66 million km), which is closer than Mercury’s orbit |
| How long is its tail? | Eight arcminutes, which is about a quarter of the size of the full moon |
When and Where to See Comet Nishimura?
Comet Nishimura is currently in the constellation Cancer and low in the dawn sky. The comet is getting brighter as it approaches the sun, reaching its perihelion (closest point to the sun) on September 17, 2023, at a distance of 34 million kilometers (or 0.23 astronomical units) from the sun. At this point, the comet may reach a magnitude as bright as 2.5, making it visible to the naked eye under dark and clear skies if everything goes as planned. Alison and I are really hopeful it can get this bright!
However, seeing Comet Nishimura will not be easy, as it will be very close to the sun’s vicinity in the sky. This means that the best time to look for the comet will be around an hour or so before sunrise or after sunset, when the sky is still dark enough but the sun is not too high above the horizon. The comet will also be very low in the sky, so you will need a clear and unobstructed view of the horizon. It’s going to be a tough one to capture as we move further into September.
To help you locate Comet Nishimura, here is a table that shows its position in the sky for some dates in September and October 2023. The table also shows the altitude (angle above the horizon) and azimuth (direction along the horizon) of the comet for an observer at latitude 40° north and longitude 0° (Greenwich, UK). We based this table on our Fridays when we head to a campground to stargaze with our RV. Also, it’s a good idea to use a star app to find out the exact position of the comet for your location and date.
| Date | Magnitude | Right Ascension | Declination | Constellation |
|---|---|---|---|---|
| August 27, 2023 | +7.8 | 8h 13m 20s | +23° 02′ 36″ | Gemini |
| September 3, 2023 | +6.5 | 9h 07m 06s | +18° 00′ 54″ | Cancer |
| September 10, 2023 | +4.8 | 10h 25m 48s | +7° 47′ 24″ | Leo |
| September 17, 2023 | +2.9 | 11h 56m 00s | -5° 12′ 00″ | Virgo |
| September 24, 2023 | +4.1 | 13h 28m 48s | -19° 12′ 00″ | Libra |
| October 1, 2023 | +6.0 | 14h 57m 36s | -31° 36′ 00″ | Scorpius |
| October 8, 2023 | +7.9 | 16h 18m 24s | -42° 24′ 00″ | Ophiuchus |
How to Observe Comet Nishimura?
To observe Comet Nishimura, you will need some basic equipment and some patience. Here are some tips to make your observation more successful:
| Tip | Details |
|---|---|
| Use binoculars or a small telescope |
|
| Find a dark and clear location |
|
| Use a star chart or app |
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| Look for a fuzzy star |
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| Enjoy the view and take pictures |
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Tip: Use our light pollution map to find a better spot to see Nishimura.
How to Compare Comet Nishimura with Other Comets?
Comet Nishimura is a rare comet that may be visible to the naked eye in September 2023…fingers crossed. How does it compare with other comets that have graced our skies in the past? Here are some criteria that we can use to compare comets:
Brightness: This is measured by the apparent magnitude of the comet, which is how bright it appears in the sky from Earth. The lower the magnitude, the brighter the comet. For example, Comet Ikeya-Seki (C/1965 S1) reached a magnitude of -10, making it one of the brightest comets ever seen.
Tail length: This is measured by the angular distance between the head and the end of the tail of the comet in the sky. The longer the tail, the more impressive the comet. For example, Comet Hyakutake (C/1996 B2) had a tail that approached 100° in length, making it one of the longest-tailed comets ever seen.
Duration: This is measured by the number of days or months that the comet is visible to the naked eye or with binoculars or telescopes. The longer the duration, the more memorable the comet. For example, Comet Hale-Bopp (C/1995 O1) was visible for 18 months, making it one of the longest-lasting comets ever seen.
Using these criteria, we can rank some of the greatest comets of our time as follows:
| Comet | Brightness | Magnitude | Tail Length | Duration |
|---|---|---|---|---|
| Hyakutake | 0 | -1.2 | 100° | 2 months |
| Hale-Bopp | -1 | 0.6 | 25° | 18 months |
| West | -3 | -0.2 | 30° | 3 weeks |
| Nishimura | 4 | 5.5 | 10° | 2 months |
| NEOWISE | 1 | 4.5 | 15° | 4 months |
| McNaught | -6 | -5.5 | 35° | 2 months |
| Ikeya-Seki | -10 | -7.0 | 30° | 2 months |
The overall brightness of a comet is determined by its magnitude, which is a measure of its apparent brightness as seen from Earth. The magnitude scale is logarithmic, meaning that each increase of one magnitude corresponds to a decrease in brightness by a factor of about 2.5 (think of something a bit similar to the Richter earthquake magnitude scale). The tail length and duration of a comet depend on various factors such as the size of the nucleus, the composition of the comet, and its distance from the Sun.
As we can see, Comet Nishimura is not as bright, long-tailed, or long-lasting as some of the other comets on this list yet. However, it will probably still be a remarkable sight that deserves our attention.
How are Comets Formed and Named?
Let’s get to some definitions.
Comets are small, icy bodies that orbit the Sun in elliptical or hyperbolic paths. They are remnants of the early solar system, when planets and moons were formed from a disk of dust and gas around the Sun. Comets are mostly made of frozen water, carbon dioxide, ammonia, methane, and other volatile substances. They also contain dust, rocks, and organic molecules.
When comets approach the Sun, they heat up and release gas and dust from their surface. This forms a coma, a fuzzy cloud that surrounds the nucleus of the comet. The solar wind and radiation pressure push the gas and dust away from the Sun, forming a tail that can stretch for millions of kilometers.
Got it? Good.
Comets are usually named after their discoverers, who can be amateur or professional astronomers. Sometimes, comets are named after spacecraft or observatories that detect them. For example, Comet Shoemaker-Levy 9 (D/1993 F2) was named after Eugene and Carolyn Shoemaker and David Levy, who discovered it using the Schmidt telescope at Palomar Observatory. Comet NEOWISE (C/2020 F3), our favorite so far, was named after the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission that detected it.
Let’s break down the naming system. It seems complex, but it’s actually pretty easy to understand once you know what you are doing.
The name of a comet consists of a letter and a number followed by a slash and another letter and number. The letter before the slash indicates the type of orbit of the comet. For example, Comet Nishimura (C/2023 P1) was discovered in the first half of August 2023, and it was the first comet discovered in that period.
So, the letter A would would be the first half of January. B would be the second half. C is the first half of February. And so on…
The possible types are:
C: A non-periodic comet, which has an orbit that does not repeat or is longer than 200 years.
P: A periodic comet, which has an orbit that repeats within 200 years.
D: A comet that has been lost or has disintegrated.
X: A comet for which no reliable orbit could be calculated, usually historical comets.
I: An interstellar object, which has an orbit that does not originate from our solar system.
A: An object that was either mistakenly identified as a comet, but is actually a minor planet, or an object on a hyperbolic orbit that does not show cometary activity.
The number before the slash indicates the order of discovery of the comet within its type. For example, Comet Nishimura (C/2023 P1) is the first non-periodic comet discovered in 2023.
The letter and number after the slash indicate the half-month and order of discovery of the comet within that half-month. The letters range from A to Y, excluding I.
Wrapping It Up
We really hope you try to view Comet Nishimura this year. It’s an unexpected and exciting comet that may be visible to the naked eye in September. However, seeing the comet will require some planning and preparation, as it will be very close to the sun in the sky. You will need to find a dark and clear location like we will be doing, use binoculars or a telescope, and look for the comet before sunrise or after sunset.
If you follow these tips, you may be rewarded with a spectacular view of this celestial visitor. Don’t miss this opportunity!
About the Authors
We are avid stargazers Jason and Alison Takacs also known as Roadtrippin’ with Takacs. With our two boys Preston and Grayson, we seek out some of the darkest skies in the country while also going on many incredible hiking and other outdoor adventures. As part-time RVers, we try to see as much of this amazing world as possible in our spare time and hope you will join us through this blog on RWT Adventures and other forms of social media as we explore the night sky and other natural wonders as hardcore astrotourists.