<p>I'm inclined to say a hard no using the casual definition of a &quot;<a href="https://en.wikipedia.org/wiki/Great_comet" rel="nofollow noreferrer">great comet</a>&quot;</p>
<blockquote>
<p>A great comet is a comet that becomes exceptionally bright. There is
no official definition; often the term is attached to comets such as
Halley's Comet, which during certain appearances are <strong>bright enough to
be noticed by casual observers who are not looking for them</strong>, and
<strong>become well known outside the astronomical community</strong>.</p>
</blockquote>
<p>So, there's a dual definition of visible brightness and/or recognition outside the astronomical community.   With that in mind, I think it's pretty clear that <a href="https://www.forbes.com/sites/startswithabang/2020/07/13/how-to-see-comet-neowise-earths-most-spectacular-comet-since-2007/#5e0dd2a55689" rel="nofollow noreferrer">Comet NEOWISE doesn't make the cut</a> due to it not being easily visible   Granted, it peaks in 2 days from now (7-23-20) but so far it's hard to see by the naked eye and that's not likely to change significantly as it peaks.</p>
<blockquote>
<p>Although it’s brighter than all but around 20 stars, its extended,
diffuse nature makes it a challenge for human eyes.</p>
</blockquote>
<p>NEOWISE is the brightest comet since <a href="https://en.wikipedia.org/wiki/C/2006_P1_(McNaught)" rel="nofollow noreferrer">comet McNaught</a>, but McNaught, with a peak mangitude of -5.5, was about 500 times brighter. (based on the estimate that Neowise is about as bright as the 20th brightest star, roughly 1.25 magnitude).  McNaught was actually brighter than peak Venus, though it probably didn't look that bright to the naked eye because it was more spread out.</p>
<p>Comet Lovejoy was a bit unusual.  It's &quot;greatness&quot; had nothing to do with it's visibility, which was unspectacular.   Lovejoy passed too close to the Sun and it lost too much material in passing, so it was much anticipated and I remember articles saying it was potentially a super-comet, but it lost everything on the other side of the sun and we never got a good view from Earth.   Perhaps if we'd been on Mercury or Earth's L3 trojan point, we'd have seen a rare and magnificent show.</p>
<p>Wikipedia doesn't list Comet Lovejoy in it's list of great comets.</p>

CC BY-SA 4.0
2020-07-21T23:10:14.557Z
That's interesting, even small spacecraft with a heliostated telescopes at L3 or maybe a trio at L3, L4 and L5 would be very useful to keep an eye on comets we can't see when things get interesting. It would be great if there were a low-cost way to get them there!
uhoh
CC BY-SA 4.0
2020-07-22T19:59:03.570Z
@uhoh I think for sun-grazers, especially those that pass on the far-side of the Sun, L3, L4 or L5 could be useful.   For more distant comets like NEOWISE, Earth orbiting telescopes are probably fine for the most part, at least to my understanding.
userLTK
CC BY-SA 4.0
2020-07-21T15:37:52.267Z
2020-07-21T15:37:52.267Z
userLTK
<p>I've seen it a few times over the last six nights.</p>
<p>The Comet of 2020? No problem.</p>
<p>Great? Not unless something very unexpected happens to it in the next few days.</p>
<p>It's a sight well worth the effort of looking and one you will remember if you get a good view of it.</p>

CC BY-SA 4.0
2020-07-21T20:14:58.263Z
2020-07-21T20:14:58.263Z
L d Bonnie
<p>Many or all comets visible to the naked eye are referred to as <em>Great Comets</em> of their year(s). Might NEOWISE too be called like this? Why or why not? Is the IAU responsible for declaration of Great Comets or another organization or no such body?</p>

CC BY-SA 4.0
2020-07-17T22:09:58.163Z
Did you read the Wiki article on [great comets](https://en.wikipedia.org/wiki/Great_comet). There's no formal definition, but I don't think NEOWISE is "great" enough.
pela
CC BY-SA 4.0
2020-07-17T23:00:57.573Z
I agree with pela that visible to the eye is not enough to be Great.
JohnHoltz
CC BY-SA 4.0
2020-07-18T06:12:15.537Z
@pela The comets McNaught and Lovejoy weren't _that_ visible either but are referred to as Great Comets anyway. Or did I miss something?
Ioannes
CC BY-SA 4.0
2020-07-21T23:07:03.410Z
Unless it gets an unexpected outburst in the next few days, I think it'll be the "Pretty Good Comet of 2020".
Mark
CC BY-SA 4.0
2020-07-22T04:51:21.203Z
I suffer quite a lot insomnia these days. Could this be due to the comet, like some have insomnia during full moons? I haven't seen the comet personally (at least as yet) but perhaps it appears _after_ I go sleeping. Is it bright enough to cause insomnia?
Ioannes
CC BY-SA 4.0
2020-07-22T17:33:25.830Z
@Greenhorn I can't speak for causes of insomnia but it's visible after sunset currently.   I've also seen it called a pre-dawn comet, which it can't be at the same time, but it could be one on the trip towards the sun and the other on the trip away.  It's currently an after sunset comet, viewable from the Northern Hemisphere.  For me, living in NYC, I'm not even going to try.  Too much light pollution.     https://heavy.com/news/2020/07/neowise-comet-map-time/#:~:text=But%20now%20you%20can%20see%20NEOWISE%20at%20night,is%20now%20visible%20just%20after%20sunset%20local%20time.
userLTK
CC BY-SA 4.0
2020-07-23T00:36:55.683Z
@userLTK, if you're far enough north, it's both a sunset and a pre-dawn comet.  Once you get above about the 45th parallel, the comet never sets.
Mark
<comets><definition>
Will NEOWISE be known as the Great Comet of 2020?
Ioannes
# Will NEOWISE be known as the Great Comet of 2020?

(Asked by: username_0 on 2020-07-17)

Many or all comets visible to the naked eye are referred to as *Great Comets* of their year(s). Might NEOWISE too be called like this? Why or why not? Is the IAU responsible for declaration of Great Comets or another organization or no such body?

**Tags:** comets, definition

> **Comments:**
> **username_1**: Did you read the Wiki article on [great comets](https://en.wikipedia.org/wiki/Great_comet). There's no formal definition, but I don't think NEOWISE is "great" enough.  
> **username_2**: I agree with username_1 that visible to the eye is not enough to be Great.  
> **username_0**: @username_1 The comets McNaught and Lovejoy weren't _that_ visible either but are referred to as Great Comets anyway. Or did I miss something?  
> **username_3**: Unless it gets an unexpected outburst in the next few days, I think it'll be the "Pretty Good Comet of 2020".  
> **username_0**: I suffer quite a lot insomnia these days. Could this be due to the comet, like some have insomnia during full moons? I haven't seen the comet personally (at least as yet) but perhaps it appears _after_ I go sleeping. Is it bright enough to cause insomnia?  
> **username_4**: @Greenhorn I can't speak for causes of insomnia but it's visible after sunset currently.   I've also seen it called a pre-dawn comet, which it can't be at the same time, but it could be one on the trip towards the sun and the other on the trip away.  It's currently an after sunset comet, viewable from the Northern Hemisphere.  For me, living in NYC, I'm not even going to try.  Too much light pollution.     https://heavy.com/news/2020/07/neowise-comet-map-time/#:~:text=But%20now%20you%20can%20see%20NEOWISE%20at%20night,is%20now%20visible%20just%20after%20sunset%20local%20time.  
> **username_3**: @username_4, if you're far enough north, it's both a sunset and a pre-dawn comet.  Once you get above about the 45th parallel, the comet never sets.  

---

## 2 answers

### Answer by username_4 on 2020-07-21. Score: 3 | Accepted answer

I'm inclined to say a hard no using the casual definition of a "[great comet](https://en.wikipedia.org/wiki/Great_comet)"

> A great comet is a comet that becomes exceptionally bright. There is
> no official definition; often the term is attached to comets such as
> Halley's Comet, which during certain appearances are **bright enough to
> be noticed by casual observers who are not looking for them**, and
> **become well known outside the astronomical community**.

So, there's a dual definition of visible brightness and/or recognition outside the astronomical community. With that in mind, I think it's pretty clear that [Comet NEOWISE doesn't make the cut](https://www.forbes.com/sites/startswithabang/2020/07/13/how-to-see-comet-neowise-earths-most-spectacular-comet-since-2007/#5e0dd2a55689) due to it not being easily visible Granted, it peaks in 2 days from now (7-23-20) but so far it's hard to see by the naked eye and that's not likely to change significantly as it peaks.

> Although it’s brighter than all but around 20 stars, its extended,
> diffuse nature makes it a challenge for human eyes.

NEOWISE is the brightest comet since [comet McNaught](https://en.wikipedia.org/wiki/C/2006_P1_(McNaught)), but McNaught, with a peak mangitude of -5.5, was about 500 times brighter. (based on the estimate that Neowise is about as bright as the 20th brightest star, roughly 1.25 magnitude). McNaught was actually brighter than peak Venus, though it probably didn't look that bright to the naked eye because it was more spread out.

Comet Lovejoy was a bit unusual. It's "greatness" had nothing to do with it's visibility, which was unspectacular. Lovejoy passed too close to the Sun and it lost too much material in passing, so it was much anticipated and I remember articles saying it was potentially a super-comet, but it lost everything on the other side of the sun and we never got a good view from Earth. Perhaps if we'd been on Mercury or Earth's L3 trojan point, we'd have seen a rare and magnificent show.

Wikipedia doesn't list Comet Lovejoy in it's list of great comets.

> **Comments:**
> **username_5**: That's interesting, even small spacecraft with a heliostated telescopes at L3 or maybe a trio at L3, L4 and L5 would be very useful to keep an eye on comets we can't see when things get interesting. It would be great if there were a low-cost way to get them there!  
> **username_4**: @username_5 I think for sun-grazers, especially those that pass on the far-side of the Sun, L3, L4 or L5 could be useful.   For more distant comets like NEOWISE, Earth orbiting telescopes are probably fine for the most part, at least to my understanding.  

---

### Answer by username_6 on 2020-07-21. Score: 1

I've seen it a few times over the last six nights.

The Comet of 2020? No problem.

Great? Not unless something very unexpected happens to it in the next few days.

It's a sight well worth the effort of looking and one you will remember if you get a good view of it.


---

