APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

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APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by APOD Robot » Thu Nov 12, 2020 5:06 am

Image Comet ATLAS and Orion's Belt

Explanation: With its closest approach to planet Earth scheduled for November 14, this Comet ATLAS (C/2020 M3) was discovered just this summer, another comet found by the NASA funded Asteroid Terrestrial-impact Last Alert System. It won't get as bright as Comet NEOWISE but it can still be spotted using binoculars, as it currently sweeps through the familiar constellation of Orion. This telephoto field from November 8, blends exposures registered on the comet with exposures registered on Orion's stars. It creates an effectively deep skyview that shows colors and details you can't quite see though, even in binoculars. The comet's telltale greenish coma is toward the upper left, above Orion's three belt stars lined-up across the frame below center. You'll also probably spot the Orion Nebula, and famous Horsehead Nebula in the stunning field of view. Of course one of Orion's belt stars is nearly 2,000 light-years away. On November 14, this comet ATLAS will fly a mere 2.9 light-minutes from Earth.

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Lasse H
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Lasse H » Thu Nov 12, 2020 10:13 am

Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?

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Ann
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Ann » Thu Nov 12, 2020 11:25 am

Lasse H wrote:
Thu Nov 12, 2020 10:13 am
Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:

Ann

And by the way, I suspect that you and I may be located not too far away from one another. Your name sounds awfully Swedish to me. Are your skies as "fifty shades of gray"-overcast and comet-unfriendly as mine?
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Ann
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Ann » Thu Nov 12, 2020 11:48 am
































Orion and Comet ATLAS are not only the subjects of today's APOD, but a widefield view of this cosmic vista has been photographed by Robin Onderka (and posted in the Recent Submissions thread). It's fun to compare the two images.

Ann
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Sa Ji Tario

Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Sa Ji Tario » Thu Nov 12, 2020 12:47 pm

In my lares, southern hemisphere, you see the belt going vertically with Mintaka first and Alnitak last, then this image is rotated 90º clockwise

Sa Ji Tario

Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Sa Ji Tario » Thu Nov 12, 2020 12:50 pm

I'll see the comet to the right of the belt

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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Lasse H » Thu Nov 12, 2020 2:30 pm

That's right, Ann, I am in Liljeholmen, Stockholm, and haven't seen the sun for some days now

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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Chris Peterson » Thu Nov 12, 2020 2:46 pm

Ann wrote:
Thu Nov 12, 2020 11:25 am
Lasse H wrote:
Thu Nov 12, 2020 10:13 am
Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east.

Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.

This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere.

In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.
Chris

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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by orin stepanek » Thu Nov 12, 2020 3:21 pm

C2020M3Orion_CharlesBracken1024.jpg
Nice photo; you can easily spot the flame & horse head along with the comet; and the Orion Nebula! 8-)
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Ann
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Ann » Thu Nov 12, 2020 4:12 pm

Chris Peterson wrote:
Thu Nov 12, 2020 2:46 pm
Ann wrote:
Thu Nov 12, 2020 11:25 am
Lasse H wrote:
Thu Nov 12, 2020 10:13 am
Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east.

Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.

This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere.

In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.
Okay, Chris. So in this APOD, Orion's "head" is down, so Orion is "upside down".

Ann
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Chris Peterson
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by Chris Peterson » Thu Nov 12, 2020 4:36 pm

Ann wrote:
Thu Nov 12, 2020 4:12 pm
Chris Peterson wrote:
Thu Nov 12, 2020 2:46 pm
Ann wrote:
Thu Nov 12, 2020 11:25 am


This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east.

Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.

This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere.

In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.
Okay, Chris. So in this APOD, Orion's "head" is down, so Orion is "upside down".

Ann
Yes, in terms of how the constellation is normally represented on paper. The problem is in relating it to a northern or southern hemisphere view.
Chris

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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by johnnydeep » Thu Nov 12, 2020 5:02 pm

A minor nit: the statement "Of course one of Orion's belt stars is nearly 2,000 light-years away." - seems to be a very out of place factoid. Yes, it links to a previous APOD that showed the true distances of Orion's stars, and yes, one of them - Alnilam - is almost 2000 ly away, and is in fact the most distant star, but the "Of course" qualifier has no context. Again, just a friendly minor nit :)
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by neufer » Thu Nov 12, 2020 7:44 pm

Chris Peterson wrote:
Thu Nov 12, 2020 2:46 pm
Ann wrote:
Thu Nov 12, 2020 11:25 am
Lasse H wrote:
Thu Nov 12, 2020 10:13 am

Am I right in assuming that the photo is "upside down" – referring to how Orion is normally shown?
This is Orion as seen from the southern hemisphere. So yes, it's "upside down" from a northerner's point of view. :wink:
No, not really. Look at Orion when it is rising (from northern mid-latitudes) and his "head" slightly leads his "feet", and his belt is perpendicular to the horizon. At setting, his feet are below the horizon, the belt lines up with the horizon and his head is rotated to the east. Like most of the sky, what we see depends much more on when we see it than it does where we see it from. Because Orion has a negative declination, it appears to rotate through a greater angle from the southern hemisphere than the northern, but that is all.

This is "upside down" for the reason suggested: the constellation represents a person, so we represent it with the head up. But we don't see it in the sky that way most of the time, from either hemisphere. In terms of astronomical convention, images are usually presented with north up, whichever hemisphere they are imaged from. This image is presented with southwest up.
Click to play embedded YouTube video.




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astrophotographer Charles Bracken :arrow:
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by orin stepanek » Fri Nov 13, 2020 12:37 pm

Where would Atlas be now! If near one of Orion's shoulders I may have seen it! :shock:
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Re: APOD: Comet ATLAS and Orion's Belt (2020 Nov 12)

Post by orin stepanek » Sat Nov 14, 2020 1:19 pm

LocationOfCometM3AtlasOnNov142020around10pmLocalTime-800x615.jpg

8-)
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