APOD: Seven Years of Halley Dust (2022 Oct 28)

Comments and questions about the APOD on the main view screen.
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APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by APOD Robot » Fri Oct 28, 2022 4:05 am

Image Seven Years of Halley Dust

Explanation: History's first known periodic comet Halley (1P/Halley) returns to the inner Solar System every 75 years or so. The famous comet made its last appearance to the naked-eye in 1986. But dusty debris from Comet Halley can be seen raining through planet Earth's skies twice a year during two annual meteor showers, the Eta Aquarids in May and the Orionids in October. Including meteors near the shower maximum on October 21, this composite view compiles Orionid meteors captured from years 2015 through 2022. About 47 bright meteors are registered in the panoramic night skyscape. Against a starry background extending along the Milky Way, the Orionid meteors all seem to radiate from a point just north of Betelgeuse in the familiar constellation of the Hunter. In the foreground are mountains in eastern Slovakia near the city of Presov.

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Ann
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by Ann » Fri Oct 28, 2022 5:43 am

APOD 28 October 2022 annotated.png
North America IC 1396 and Cocoon Jolind.png
North America Nebula, IC 1396 (Elephant Trunk Nebula)
and Cocoon Nebula. Photo: Jolind of Astrobin.

Do click to see full size of the annotated APOD. As for the other image I posted, the Cocoon Nebula was the APOD just two days ago, and I wanted to show you where tiny this nebula is in the sky. You can just barely - barely! - find it in the APOD at upper right.

The Cocoon Nebula is about twice as far away as the North America Nebula and IC 1396, so the Cocoon is not quite as small as it appears to be when we compare it to nebulas that are much closer. Still, it is tiny. And no wonder, since it is being ionized by a single star that isn't even spectral class O, but "just" B1. Actually, spectral class B1 is the lower "spectral class and temperature limit" where stars are able to ionize a red emission nebula.

Ann
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by orin stepanek » Fri Oct 28, 2022 2:03 pm

OrionidsOrion_LuShupei_960.jpg
I like this view! Normally I don't get interested in comet dust; but
this one is nice! 8-)
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by johnnydeep » Fri Oct 28, 2022 9:29 pm

What's that fairly bright star that appears to be at almost the exact radiant point? It's not in Ann's annotated image.

[ PS - beautiful pic BTW: looks like a fireworks explosion! ]
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by Ann » Sat Oct 29, 2022 3:23 am

johnnydeep wrote: Fri Oct 28, 2022 9:29 pm What's that fairly bright star that appears to be at almost the exact radiant point? It's not in Ann's annotated image.

[ PS - beautiful pic BTW: looks like a fireworks explosion! ]

I guess you mean Alhena (Gamma Geminorum) at the foot of Gemini? (The cyan line across Gemini in the map, by the way, is the ecliptic.)

Ann
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by jimfish » Sat Oct 29, 2022 11:35 am

Ann wrote: Sat Oct 29, 2022 3:23 am
johnnydeep wrote: Fri Oct 28, 2022 9:29 pm What's that fairly bright star that appears to be at almost the exact radiant point? It's not in Ann's annotated image.

[ PS - beautiful pic BTW: looks like a fireworks explosion! ]

I guess you mean Alhena (Gamma Geminorum) at the foot of Gemini? (The cyan line across Gemini in the map, by the way, is the ecliptic.)

Ann
I think yes, Johnnydip meant it. By the way, Orin Stepanek, a very beautiful view, I like it too.

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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by johnnydeep » Sat Oct 29, 2022 1:10 pm

jimfish wrote: Sat Oct 29, 2022 11:35 am
Ann wrote: Sat Oct 29, 2022 3:23 am
johnnydeep wrote: Fri Oct 28, 2022 9:29 pm What's that fairly bright star that appears to be at almost the exact radiant point? It's not in Ann's annotated image.

[ PS - beautiful pic BTW: looks like a fireworks explosion! ]

I guess you mean Alhena (Gamma Geminorum) at the foot of Gemini? (The cyan line across Gemini in the map, by the way, is the ecliptic.)

Ann
I think yes, Johnnydeep meant it. By the way, Orin Stepanek, a very beautiful view, I like it too.
Seems like that's it, as long as that's the same as the one that I indicate here in red:

orionids radiant point.JPG

But then, if that's the (seemingly most accurate) radiant point, why aren't these called the Geminids instead of the Orionids?
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by Ann » Sat Oct 29, 2022 3:31 pm


Alhena is quite close to Orion in the sky, so I guess it is "almost" in Orion? :wink:

The "real" Geminids have a radiant point close to Castor, and "everybody" - well, more or less - knows that Castor is in Gemini, don't they?

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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by johnnydeep » Sat Oct 29, 2022 4:17 pm

Ann wrote: Sat Oct 29, 2022 3:31 pm

Alhena is quite close to Orion in the sky, so I guess it is "almost" in Orion? :wink:

The "real" Geminids have a radiant point close to Castor, and "everybody" - well, more or less - knows that Castor is in Gemini, don't they?

Ann
I guess I'll chalk it up to "hysterical raisins" and leave it at that. :ssmile:
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Re: APOD: Seven Years of Halley Dust (2022 Oct 28)

Post by Emilyyrt546 » Fri Nov 04, 2022 4:48 pm

Ann wrote: Fri Oct 28, 2022 5:43 am
APOD 28 October 2022 annotated.png
North America IC 1396 and Cocoon Jolind.png
North America Nebula, IC 1396 (Elephant Trunk Nebula)
and Cocoon Nebula. Photo: Jolind of Astrobin.

Do click to see full size of the annotated APOD. As for the other image I posted, the Cocoon Nebula was the APOD just two days ago, and I wanted to show you where tiny this nebula is in the sky. You can just barely - barely! - find it in the APOD at upper right.

The Cocoon Nebula is about twice as far away as the North America Nebula and IC 1396, so the Cocoon is not quite as small as it appears to be when we compare it to nebulas that are much closer. Still, it is tiny. And no wonder, since it is being ionized by a single star that isn't even spectral class O, but "just" B1. Actually, spectral class B1 is the lower "spectral class and temperature limit" where stars are able to ionize a red emission nebula.

Ann
The picture is nice and clear, I have observed many things from this photo, thanks
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