<p>I took the <a href="https://en.wikipedia.org/wiki/List_of_meteor_showers" rel="nofollow noreferrer">Wikipedia List of Meteor Showers</a> and plotted their Alt/Az coordinates as if viewed from Lat/Lon 0°,0° at Sunset.  There are close enough contenders that the answer will likely change based on the observer's location.  I created a <a href="https://jsfiddle.net/gmiller123456/Lg5v7bnc/1/" rel="nofollow noreferrer">JSFiddle</a> so you can try it for other locations.</p>
<p>It looks like the answer is the <strong>Draconids</strong></p>
<p>You'll probably have to zoom in to see the text on the image, but making the font larger just creates more collisions and doesn't make it easier to read.  I spot checked a few, and they all seem correct, but comment below if you find any errors.  Notice North is to the right, and West is down (that's just the default way the sin/cos functions work and I didn't really have time to change it).
<a href="https://i.sstatic.net/f5i49Fc6.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/f5i49Fc6.png" alt="graph" /></a></p>

CC BY-SA 4.0
2024-08-28T00:28:21.393Z
I see, *this is cool!* The zenith is in the center, the horizon is the circle. I'll try to "fiddle" (thanks for that!) but I'm guessing longitude won't have a large effect (it's equivalent to moving the date of maxima by a fraction of a day) while latitude will have a visible effect. I can't wait to find out :-)
uhoh
CC BY-SA 4.0
2024-08-28T16:00:28.967Z
Yea, it's essentially an Alt/Az chart just like any other.  Though there's certainly room to make it prettier for anyone that wants to.  I was hoping for some interesting pattern to emerge, but the only real intriguing pattern is that it's North heavy.
Greg Miller
CC BY-SA 4.0
2024-08-27T20:04:09.083Z
2024-08-27T20:04:09.083Z
Greg Miller
<p>When it finally gets answered, answers to <a href="https://astronomy.stackexchange.com/q/37134/7982">RA/Dec of a meteor shower&#39;s radiant point based on its associated comet&#39;s orbit; simple set of equations? &quot;Classic&quot; early reference to cite?</a> will help us understand why the radiant points of meteor showers tend to be closer to east than west after sunset and before midnight, but some comet orbits could potentially produce meteor showers who's radiants could be near the zenith at sunset and set in the west around midnight.</p>
<p><strong>Question:</strong> What meteor shower's radiant appears furthest west after sunset? What is it about the associated comet's orbit that makes this so?</p>

CC BY-SA 4.0
2020-08-15T07:22:27.587Z
Not an answer yet: the slower the comet (at earth orbit), the more West the meteors appear (think of driving through rain: the faster you go, the more you become wet from the front). Yet in your question is strange. "After sunset" is variable and the answer will vary from day to day - depending on what is visible. You actually seem to want to ask about the "apparent shift of radiant".
planetmaker
CC BY-SA 4.0
2020-08-15T07:31:30.577Z
@planetmaker my question is well-enough posed and I'm familliar with the orbital mechanics. What's needed to answer this question is not a tutorial on the geometry, but an investigation of a table of meteor showers and a comparison of the radiant's RA to the Earth's position around the ecliptic relative to the September equinox. If one can *demonstrate* that the answer depends on latitude; i.e. different showers answer the question for different latitudes, I'll award fictitious "bonus points" :-)
uhoh
CC BY-SA 4.0
2020-08-15T07:46:55.263Z
effectively you are thus asking for a table of orbital speeds of comet when crossing Earth orbit. But then you should ask that, if you are not interested in a geometric explanation.
planetmaker
CC BY-SA 4.0
2020-08-15T07:50:56.230Z
And I maintaint that you are effectively asking about 'radiant shift'. Asking about the west most raidiant is like asking about the west most star. That makes only sense for a very particular time. And changes every minute.
planetmaker
CC BY-SA 4.0
2020-08-15T07:51:58.513Z
@planetmaker  No, my question asks specifically about the radiant positions, which are well tabulated. The orbital speeds and directions at the intersections with Earth's orbit determine the radiant positions, once you have those you don't need to go backwards. My linked and currently unanswered question about calculation the radiant positions address this.  I disagree, My question asks for ***furthest west after sunset*** and is sufficiently clear and answerable; let's wait for an answer that demonstrates that.
uhoh
CC BY-SA 4.0
2020-08-15T13:23:32.047Z
I think the Geminids are the shower to beat.
Mike G
CC BY-SA 4.0
2024-08-19T12:47:39.367Z
How far West a radiant will appear, as well as the Sunset time, depends on the observer's position on Earth.  There will certainly be many showers visible from the arctic circles that will be visible in every direction as the Earth rotates.  So you either need to specify a location, or rephrase it in terms like "which has a radiant closest to, but West of, the Sun in RA".  Some showers are also visible for weeks, but tend to have a definite peak on a specific day, so you might want to specify if you're just referring to the peak or the entire visibility period.
Greg Miller
CC BY-SA 4.0
2024-08-19T12:52:33.510Z
@planetmaker, I think you have that backwards, the slower a comet moves, the further East it will appear.  Because the Earth is moving towards the East, and the Earth's motion would be the more dominant factor the slower the comet moves.  But that's only a generalized rule, the comet's trajectory will also play a big role.
Greg Miller
CC BY-SA 4.0
2024-08-19T12:54:20.753Z
Good resources to start with would be the IAU meteor shower list
https://www.ta3.sk/IAUC22DB/MDC2022/Roje/roje_lista.php?corobic_roje=0&sort_roje=0

And the IMO's meteor shower calendar: https://www.imo.net/resources/calendar/
Greg Miller
CC BY-SA 4.0
2024-08-19T13:19:20.667Z
@GregMiller yes, you're right, I got it wrong 4 years ago. Slower meteoroids mean a radiant more in the East, indeed, for precisely the reason you mention. I still don't get the premise of this question, though.
planetmaker
CC BY-SA 4.0
2024-08-19T23:23:05.993Z
@planetmaker if we choose a location on Earth (let's say somewhere on the equator) and start with a set of meteor showers, each shower's radiant will have a different position in the sky at sunset. One of them will be further west than all the others. The task is to name that shower. I don't see much of a premise at all here, except that showers have something called radiant points on the celestial sphere, that they are at about the same location each year, and that they are not all the same point. I can change "after sunset" to "at sunset" or "one hour after sunset" if that helps.
uhoh
CC BY-SA 4.0
2024-08-19T23:47:12.670Z
@uhoh but the answer will vary from day to day, like 'what is the most Western Messier object at sunset'. The answer obviously depends on latitude. And how long do you consider a Meteor stream active around their peak or what minimum hourly rate to still consider it in the list? Do you assume a gaussian distribution around the peak date with some fwhm temporal distribution?
planetmaker
CC BY-SA 4.0
2024-08-20T00:56:08.297Z
@planetmaker meteor showers are pretty short. Any reasonable person answering my question would choose the predicted maximum date. The uncertainty you are tlaking about is likely way too small to affect which shower answers the question.
uhoh
CC BY-SA 4.0
2024-08-20T07:35:26.970Z
My yearbook gives ranges of about a month of activity for Individual meteor streams
planetmaker
CC BY-SA 4.0
2024-08-20T22:45:29.547Z
@planetmaker I guess we've established that you won't be answering, and I understand that since some showers are long {though [some are quite short](https://astronomy.stackexchange.com/q/34018/7982) as well) and a few even can have more than one maximum, you would hesitate to answer. But I have a hunch that there will still be a winner. So I'll do the following. I'll bounty the question, and if there's no answer posted after the bounty expires (7 days + 1 invisible grace period day) I'll attempt to answer this myself.
uhoh
CC BY-SA 4.0
2024-08-20T22:48:54.183Z
@GregMiller I've just added a bounty.
uhoh
CC BY-SA 4.0
2024-08-20T22:49:16.590Z
@MikeG ...ditto
uhoh
<solar-system><orbital-mechanics><comets><meteor-shower>
What meteor shower's radiant appears furthest west after sunset, and why?
uhoh
# What meteor shower's radiant appears furthest west after sunset, and why?

(Asked by: username_0 on 2020-08-15)

When it finally gets answered, answers to [RA/Dec of a meteor shower's radiant point based on its associated comet's orbit; simple set of equations? "Classic" early reference to cite?](https://astronomy.stackexchange.com/q/37134/7982) will help us understand why the radiant points of meteor showers tend to be closer to east than west after sunset and before midnight, but some comet orbits could potentially produce meteor showers who's radiants could be near the zenith at sunset and set in the west around midnight.

**Question:** What meteor shower's radiant appears furthest west after sunset? What is it about the associated comet's orbit that makes this so?

**Tags:** solar-system, orbital-mechanics, comets, meteor-shower

> **Comments:**
> **username_1**: Not an answer yet: the slower the comet (at earth orbit), the more West the meteors appear (think of driving through rain: the faster you go, the more you become wet from the front). Yet in your question is strange. "After sunset" is variable and the answer will vary from day to day - depending on what is visible. You actually seem to want to ask about the "apparent shift of radiant".  
> **username_0**: @username_1 my question is well-enough posed and I'm familliar with the orbital mechanics. What's needed to answer this question is not a tutorial on the geometry, but an investigation of a table of meteor showers and a comparison of the radiant's RA to the Earth's position around the ecliptic relative to the September equinox. If one can *demonstrate* that the answer depends on latitude; i.e. different showers answer the question for different latitudes, I'll award fictitious "bonus points" :-)  
> **username_1**: effectively you are thus asking for a table of orbital speeds of comet when crossing Earth orbit. But then you should ask that, if you are not interested in a geometric explanation.  
> **username_1**: And I maintaint that you are effectively asking about 'radiant shift'. Asking about the west most raidiant is like asking about the west most star. That makes only sense for a very particular time. And changes every minute.  
> **username_0**: @username_1  No, my question asks specifically about the radiant positions, which are well tabulated. The orbital speeds and directions at the intersections with Earth's orbit determine the radiant positions, once you have those you don't need to go backwards. My linked and currently unanswered question about calculation the radiant positions address this.  I disagree, My question asks for ***furthest west after sunset*** and is sufficiently clear and answerable; let's wait for an answer that demonstrates that.  
> **username_2**: I think the Geminids are the shower to beat.  
> **username_3**: How far West a radiant will appear, as well as the Sunset time, depends on the observer's position on Earth.  There will certainly be many showers visible from the arctic circles that will be visible in every direction as the Earth rotates.  So you either need to specify a location, or rephrase it in terms like "which has a radiant closest to, but West of, the Sun in RA".  Some showers are also visible for weeks, but tend to have a definite peak on a specific day, so you might want to specify if you're just referring to the peak or the entire visibility period.  
> **username_3**: @username_1, I think you have that backwards, the slower a comet moves, the further East it will appear.  Because the Earth is moving towards the East, and the Earth's motion would be the more dominant factor the slower the comet moves.  But that's only a generalized rule, the comet's trajectory will also play a big role.  
> **username_3**: Good resources to start with would be the IAU meteor shower list https://www.ta3.sk/IAUC22DB/MDC2022/Roje/roje_lista.php?corobic_roje=0&sort_roje=0  And the IMO's meteor shower calendar: https://www.imo.net/resources/calendar/  
> **username_1**: @username_3 yes, you're right, I got it wrong 4 years ago. Slower meteoroids mean a radiant more in the East, indeed, for precisely the reason you mention. I still don't get the premise of this question, though.  
> **username_0**: @username_1 if we choose a location on Earth (let's say somewhere on the equator) and start with a set of meteor showers, each shower's radiant will have a different position in the sky at sunset. One of them will be further west than all the others. The task is to name that shower. I don't see much of a premise at all here, except that showers have something called radiant points on the celestial sphere, that they are at about the same location each year, and that they are not all the same point. I can change "after sunset" to "at sunset" or "one hour after sunset" if that helps.  
> **username_1**: @username_0 but the answer will vary from day to day, like 'what is the most Western Messier object at sunset'. The answer obviously depends on latitude. And how long do you consider a Meteor stream active around their peak or what minimum hourly rate to still consider it in the list? Do you assume a gaussian distribution around the peak date with some fwhm temporal distribution?  
> **username_0**: @username_1 meteor showers are pretty short. Any reasonable person answering my question would choose the predicted maximum date. The uncertainty you are tlaking about is likely way too small to affect which shower answers the question.  
> **username_1**: My yearbook gives ranges of about a month of activity for Individual meteor streams  
> **username_0**: @username_1 I guess we've established that you won't be answering, and I understand that since some showers are long {though [some are quite short](https://astronomy.stackexchange.com/q/34018/7982) as well) and a few even can have more than one maximum, you would hesitate to answer. But I have a hunch that there will still be a winner. So I'll do the following. I'll bounty the question, and if there's no answer posted after the bounty expires (7 days + 1 invisible grace period day) I'll attempt to answer this myself.  
> **username_0**: @username_3 I've just added a bounty.  
> **username_0**: @username_2 ...ditto  

---

## 1 answers

### Answer by username_3 on 2024-08-27. Score: 2

I took the [Wikipedia List of Meteor Showers](https://en.wikipedia.org/wiki/List_of_meteor_showers) and plotted their Alt/Az coordinates as if viewed from Lat/Lon 0°,0° at Sunset. There are close enough contenders that the answer will likely change based on the observer's location. I created a [JSFiddle](https://jsfiddle.net/gmiller123456/Lg5v7bnc/1/) so you can try it for other locations.

It looks like the answer is the **Draconids**

You'll probably have to zoom in to see the text on the image, but making the font larger just creates more collisions and doesn't make it easier to read. I spot checked a few, and they all seem correct, but comment below if you find any errors. Notice North is to the right, and West is down (that's just the default way the sin/cos functions work and I didn't really have time to change it).
[![graph](https://i.sstatic.net/f5i49Fc6.png)](https://i.sstatic.net/f5i49Fc6.png)

> **Comments:**
> **username_0**: I see, *this is cool!* The zenith is in the center, the horizon is the circle. I'll try to "fiddle" (thanks for that!) but I'm guessing longitude won't have a large effect (it's equivalent to moving the date of maxima by a fraction of a day) while latitude will have a visible effect. I can't wait to find out :-)  
> **username_3**: Yea, it's essentially an Alt/Az chart just like any other.  Though there's certainly room to make it prettier for anyone that wants to.  I was hoping for some interesting pattern to emerge, but the only real intriguing pattern is that it's North heavy.  

---

