APOD: Jupiter by Moonlight (2023 Nov 03)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 5314
Joined: Fri Dec 04, 2009 3:27 am

APOD: Jupiter by Moonlight (2023 Nov 03)

Post by APOD Robot » Fri Nov 03, 2023 4:05 am

Image Jupiter by Moonlight

Explanation: That bright beacon you've seen rising in the east just after sunset is Jupiter. Climbing high in midnight skies, our Solar System's ruling gas giant was at its 2023 opposition, opposite the Sun in planet Earth's sky, on November 2. But only a few days earlier, on October 28, the Moon was at its own opposition. Then both Full Moon and Jupiter could share this telephoto field of view. The celestial scene is composed from two exposures, one long and one short, blended to record bright planet and even brighter Moon during that evening's partial lunar eclipse. Moonlight shining through the thin, high clouds over northern Italy creates the colorful iridescence and lunar corona. Look closely and you'll also spot some of Jupiter's Galilean moons.

<< Previous APOD This Day in APOD Next APOD >>

andyc
Ensign
Posts: 13
Joined: Sat Sep 06, 2014 12:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by andyc » Fri Nov 03, 2023 5:34 am

A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.

Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.

Beills
Asternaut
Posts: 1
Joined: Fri Nov 03, 2023 8:57 am

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Beills » Fri Nov 03, 2023 8:59 am

andyc wrote: Fri Nov 03, 2023 5:34 am A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.
online games
Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.
I also think that it's hard to take pic of Moon in context with other objects.
Last edited by Beills on Sat Nov 04, 2023 1:10 am, edited 1 time in total.

smitty
Science Officer
Posts: 129
Joined: Tue Jul 04, 2006 9:57 am

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by smitty » Fri Nov 03, 2023 12:45 pm

Is Jupiter the tiny little dot in the lower left corner of this image? If so, there is no way I'll ever be seeing any of its moons. Sorry, but the effect of this image is disappointing and underwhelming.

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 1:55 pm

smitty wrote: Fri Nov 03, 2023 12:45 pm Is Jupiter the tiny little dot in the lower left corner of this image? If so, there is no way I'll ever be seeing any of its moons. Sorry, but the effect of this image is disappointing and underwhelming.
Yes, that tiny dot is the Solar System's most massive planet. And its major moons are best seen by zooming in quite a bit:

a few of jupiters moons.png
You do not have the required permissions to view the files attached to this post.
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 1:56 pm

andyc wrote: Fri Nov 03, 2023 5:34 am A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.

Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.
Define "completely true to the source material".
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
Chris Peterson
Abominable Snowman
Posts: 18049
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Chris Peterson » Fri Nov 03, 2023 2:40 pm

andyc wrote: Fri Nov 03, 2023 5:34 am A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.

Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.
The problem is that this image was made after the eclipse, so we should not be able to see the shadow on the Moon. Everything else is fine... assuming the image was made at 12:53am (local) on October 29... about three hours after we would have seen the shadow as it's presented in the image. Otherwise, the size of the Moon, the distance from Jupiter, the rotation of the Moon, and the positions of the Galilean moons are all exactly where they should be.

So this image does not represent a realistic astronomical event given that it displays a dynamically changing scene at two completely different times.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 3:10 pm

Chris Peterson wrote: Fri Nov 03, 2023 2:40 pm
andyc wrote: Fri Nov 03, 2023 5:34 am A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.

Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.
The problem is that this image was made after the eclipse, so we should not be able to see the shadow on the Moon. Everything else is fine... assuming the image was made at 12:53am (local) on October 29... about three hours after we would have seen the shadow as it's presented in the image. Otherwise, the size of the Moon, the distance from Jupiter, the rotation of the Moon, and the positions of the Galilean moons are all exactly where they should be.

So this image does not represent a realistic astronomical event given that it displays a dynamically changing scene at two completely different times.
The image author had this caption about it on her site:
Partial lunar eclipse of 28 October 2023.
I captured the Moon during the maximum of the eclipse with a crown and with planet Jupiter.
So, is that not correct given the moon image we see, along with Jupiter in that same position at the time the exposure of the moon was taken?
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
Chris Peterson
Abominable Snowman
Posts: 18049
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Chris Peterson » Fri Nov 03, 2023 3:20 pm

johnnydeep wrote: Fri Nov 03, 2023 3:10 pm
Chris Peterson wrote: Fri Nov 03, 2023 2:40 pm
andyc wrote: Fri Nov 03, 2023 5:34 am A nice little scene. I am just a touch concerned that the Moon in the image is about 10% too large for the scene over northern Italy (image scale of Jupiter & moons 19.5"/pixel; image scale of the Moon 18.1"/pixel), and also the Moon is rotated about 15 degrees clockwise from its true relationship to Jupiter that night.

Ordinarily this wouldn't really matter much at all, as the overall integrity of the scene is not broken by those differences, and nothing has been introduced from elsewhere. I have absolutely no doubts about the basic veracity of the picture and description - a very nice scene captured well by the photographer. But given the major issues with an APOD two days ago, it's a shame to have another image not quite completely true to the source material. The Moon is hard to image in context with other objects, and care ought to be taken to ensure that size and rotation are kept (unless explicitly stated) when layering in second exposures.
The problem is that this image was made after the eclipse, so we should not be able to see the shadow on the Moon. Everything else is fine... assuming the image was made at 12:53am (local) on October 29... about three hours after we would have seen the shadow as it's presented in the image. Otherwise, the size of the Moon, the distance from Jupiter, the rotation of the Moon, and the positions of the Galilean moons are all exactly where they should be.

So this image does not represent a realistic astronomical event given that it displays a dynamically changing scene at two completely different times.
The image author had this caption about it on her site:
Partial lunar eclipse of 28 October 2023.
I captured the Moon during the maximum of the eclipse with a crown and with planet Jupiter.
So, is that not correct given the moon image we see, along with Jupiter in that same position at the time the exposure of the moon was taken?
I don't see how. The distance between the Moon and Jupiter is not consistent with the eclipse maximum.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 3:39 pm

Chris Peterson wrote: Fri Nov 03, 2023 3:20 pm
johnnydeep wrote: Fri Nov 03, 2023 3:10 pm
Chris Peterson wrote: Fri Nov 03, 2023 2:40 pm

The problem is that this image was made after the eclipse, so we should not be able to see the shadow on the Moon. Everything else is fine... assuming the image was made at 12:53am (local) on October 29... about three hours after we would have seen the shadow as it's presented in the image. Otherwise, the size of the Moon, the distance from Jupiter, the rotation of the Moon, and the positions of the Galilean moons are all exactly where they should be.

So this image does not represent a realistic astronomical event given that it displays a dynamically changing scene at two completely different times.
The image author had this caption about it on her site:
Partial lunar eclipse of 28 October 2023.
I captured the Moon during the maximum of the eclipse with a crown and with planet Jupiter.
So, is that not correct given the moon image we see, along with Jupiter in that same position at the time the exposure of the moon was taken?
I don't see how. The distance between the Moon and Jupiter is not consistent with the eclipse maximum.
So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
Chris Peterson
Abominable Snowman
Posts: 18049
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Chris Peterson » Fri Nov 03, 2023 4:07 pm

johnnydeep wrote: Fri Nov 03, 2023 3:39 pm
Chris Peterson wrote: Fri Nov 03, 2023 3:20 pm
johnnydeep wrote: Fri Nov 03, 2023 3:10 pm

The image author had this caption about it on her site:



So, is that not correct given the moon image we see, along with Jupiter in that same position at the time the exposure of the moon was taken?
I don't see how. The distance between the Moon and Jupiter is not consistent with the eclipse maximum.
So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
orin stepanek
Plutopian
Posts: 8200
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by orin stepanek » Fri Nov 03, 2023 4:35 pm

_GHR7338_3_firma_picc1024.jpg
Ah Jupiter; I dub thee King of the Solar System! 🤴
IridescenzaLunaPleiadi1024.jpg
Nice coloration!
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 6:33 pm

Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
johnnydeep wrote: Fri Nov 03, 2023 3:39 pm
Chris Peterson wrote: Fri Nov 03, 2023 3:20 pm

I don't see how. The distance between the Moon and Jupiter is not consistent with the eclipse maximum.
So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Ok, thanks. So a "completely true to the source material" (as the poster upthread said) must mean that all displayed objects are at the actual positions and orientations they were in reality at the time(s) the images were taken, and if there ARE multiple images taken using different exposures at different times, that fact should be clearly spelled out.
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
Chris Peterson
Abominable Snowman
Posts: 18049
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Chris Peterson » Fri Nov 03, 2023 6:54 pm

johnnydeep wrote: Fri Nov 03, 2023 6:33 pm
Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
johnnydeep wrote: Fri Nov 03, 2023 3:39 pm

So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Ok, thanks. So a "completely true to the source material" (as the poster upthread said) must mean that all displayed objects are at the actual positions and orientations they were in reality at the time(s) the images were taken, and if there ARE multiple images taken using different exposures at different times, that fact should be clearly spelled out.
This looks like a perfectly reasonable HDR (i.e. multiple exposure time composite). The only problem is the eclipse shadow, which should not be there. Was not there when the Moon-Jupiter image was made. Even if so labeled, that shadow image should never have been added, because it results in an image of an event that didn't happen.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

User avatar
johnnydeep
Commodore
Posts: 2711
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by johnnydeep » Fri Nov 03, 2023 7:02 pm

Chris Peterson wrote: Fri Nov 03, 2023 6:54 pm
johnnydeep wrote: Fri Nov 03, 2023 6:33 pm
Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Ok, thanks. So a "completely true to the source material" (as the poster upthread said) must mean that all displayed objects are at the actual positions and orientations they were in reality at the time(s) the images were taken, and if there ARE multiple images taken using different exposures at different times, that fact should be clearly spelled out.
This looks like a perfectly reasonable HDR (i.e. multiple exposure time composite). The only problem is the eclipse shadow, which should not be there. Was not there when the Moon-Jupiter image was made. Even if so labeled, that shadow image should never have been added, because it results in an image of an event that didn't happen.
✔️
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

andyc
Ensign
Posts: 13
Joined: Sat Sep 06, 2014 12:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by andyc » Sat Nov 04, 2023 12:31 am

Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
johnnydeep wrote: Fri Nov 03, 2023 3:39 pm
Chris Peterson wrote: Fri Nov 03, 2023 3:20 pm

I don't see how. The distance between the Moon and Jupiter is not consistent with the eclipse maximum.
So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Hi Chris and Johnny, I think the explanation is a lot more innocent in this case. I think the images were taken at the correct date and time (eclipse phase and Galilean Moons position are both close enough to be correct IMHO. First exposure was a wider one with Moon and Jupiter, and the Moon is overexposed so that the Galilean Moons show up. The overexposure blooms the Moon image to about 10% larger. The photographer takes a second image well exposed for the eclipse shadow very shortly afterwards, possibly at a different focal length. When she went to scale & overlay the correctly-exposed Moon image on the overexposed Moon, she slightly misjudged the scaling of the Moon due to the bloomed and whited-out Moon in her first image. So Moon and Jupiter are in the right position for the event, but the Moon is just a bit too big, which throws off the separation calculation. For some reason she slightly mis-corrected the Moon's rotation, partly as there wouldn't have been a reference in the first image for the lunar features.

The resulting image is a fair representation of the scene, just with some oddities in there. I think it's a pretty faithful image - she really did take the shots at the time and all elements are there, and I don't think in this case there's any intent at all to deceive the viewer. But a couple of slips in the processing aren't quite ideal. It must have been a lovely sight from northern Italy that night!
Last edited by andyc on Sat Nov 04, 2023 12:37 am, edited 1 time in total.

User avatar
Chris Peterson
Abominable Snowman
Posts: 18049
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by Chris Peterson » Sat Nov 04, 2023 12:37 am

andyc wrote: Sat Nov 04, 2023 12:31 am
Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
johnnydeep wrote: Fri Nov 03, 2023 3:39 pm

So you're saying that the eclipse maximum at her location was at 12:53 AM her time? (How do we know here location?) But that's not what the moon would have looked like then?
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Hi Chris and Johnny, I think the explanation is a lot more innocent in this case. I think the images were taken at the correct date and time (eclipse phase and Galilean Moons position are both close enough to be correct IMHO. First exposure was a wider one with Moon and Jupiter, and the Moon is overexposed so that the Galilean Moons show up. The overexposure blooms the Moon image to about 10% larger. The photographer takes a second image well exposed for the eclipse shadow very shortly afterwards, possibly at a different focal length. When she went to scale & overlay the correctly-exposed Moon image on the overexposed Moon, she slightly misjudged the scaling of the Moon due to the bloomed and whited-out Moon in her first image. So Moon and Jupiter are in the right position for the event, but the Moon is just a bit too big, which throws off the separation calculation. For some reason she slightly mis-corrected the Moon's rotation, partly as there wouldn't have been a reference in the first image for the lunar features.

The resulting image is a fair representation of the scene, just with some oddities in there. It's why I called it "true to the source material" - she really did take the shots at the time and all elements are there, and I don't think in this case there's any intent at all to deceive the viewer. It must have been a lovely sight from northern Italy that night!
An overexposed image of the Moon should still have the right angular distance between the center of that Moon and Jupiter.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
https://www.cloudbait.com

andyc
Ensign
Posts: 13
Joined: Sat Sep 06, 2014 12:57 pm

Re: APOD: Jupiter by Moonlight (2023 Nov 03)

Post by andyc » Sat Nov 04, 2023 12:55 am

Chris Peterson wrote: Sat Nov 04, 2023 12:37 am
andyc wrote: Sat Nov 04, 2023 12:31 am
Chris Peterson wrote: Fri Nov 03, 2023 4:07 pm
My assumption is that the image was made near Cortina, Italy (consistent with "northern Italy" and the imager's bio). In which case, the eclipse maximum was at 22:14 on 28 October (local time). At that time, the Moon and Jupiter were 6.19 degrees apart. In the image (taking the angular diameter of the Moon at the time to be 32.3 arcmin), Jupiter is 5.17 degrees from the Moon. That actual separation did not occur until later, at 00:53 on 29 October. After the eclipse. The separation, angle of the Moon, and moons of Jupiter are all consistent with an image made well after the eclipse was over, when no shadow would have been visible.
Hi Chris and Johnny, I think the explanation is a lot more innocent in this case. I think the images were taken at the correct date and time (eclipse phase and Galilean Moons position are both close enough to be correct IMHO. First exposure was a wider one with Moon and Jupiter, and the Moon is overexposed so that the Galilean Moons show up. The overexposure blooms the Moon image to about 10% larger. The photographer takes a second image well exposed for the eclipse shadow very shortly afterwards, possibly at a different focal length. When she went to scale & overlay the correctly-exposed Moon image on the overexposed Moon, she slightly misjudged the scaling of the Moon due to the bloomed and whited-out Moon in her first image. So Moon and Jupiter are in the right position for the event, but the Moon is just a bit too big, which throws off the separation calculation. For some reason she slightly mis-corrected the Moon's rotation, partly as there wouldn't have been a reference in the first image for the lunar features.

The resulting image is a fair representation of the scene, just with some oddities in there. It's why I called it "true to the source material" - she really did take the shots at the time and all elements are there, and I don't think in this case there's any intent at all to deceive the viewer. It must have been a lovely sight from northern Italy that night!
An overexposed image of the Moon should still have the right angular distance between the center of that Moon and Jupiter.

For an approximate image time of 22:07 local time (a few minutes here and there won't matter), and measured off an enlarged version of the image:
The image scale of the frame as calculated from the Galilean Moons (Io to Ganymede is ~22.3 pixels, ~7.92arcmin) is 2.816pixels/arcmin
The image scale as calculated from the centre of the Moon to the centre of Jupiter (~1049pixels, ~372arcmin) is 2.819pixels/arcmin

Even allowing for measurement and time error, these are far within uncertainty bounds for this sort of measurement! I'm completely satisfied that the Moon, Jupiter and the Galilean Moons are all in the right place, just the Moon is a little too large (and while that is a pity it's not quite spot on, I really doubt there was any intent to deceive).