APOD: Planets Around a Total Eclipse (2024 Apr 10)

[APOD Robot]

Planets Around a Total Eclipse

Explanation: What wonders appear when the Moon blocks the Sun? For many eager observers of Monday’s total eclipse of the Sun, the suddenly dark sky included the expected corona and two (perhaps surprise) planets: Venus and Jupiter. Normally, in recent days, Venus is visible only in the morning when the Sun and Jupiter are below the horizon, while Jupiter appears bright only in the evening. On Monday, though, for well-placed observers, both planets became easily visible during the day right in line with the totally eclipsed Sun. This line was captured Monday afternoon in the featured image from Mount Nebo, Arkansas, USA, along with a line of curious observers — and a picturesque tree.

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[Lasse H]

Why is there a small dark spot in the middle of the sun (that isn't there to see)? I have seen this curious phenomenon in some of my own amateur photos (taken during other eclipses).

[Ann]

Why is there a small dark spot in the middle of the sun (that isn't there to see)? I have seen this curious phenomenon in some of my own amateur photos (taken during other eclipses).

My guess is that "the small dark spot in the middle of the sun" is the lunar disk. The bright ring around this small dark spot is the brilliant solar corona.

Planets Around a Total Eclipse. Image Credit: Stéphane Vetter (Nuits sacrées)

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A solar eclipse. Credit: THANAKRIT SANTIKUNAPORN/Shutterstock

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Ann

[Lasse H]

Yes, that is a possible explanation, but I wonder if there could be something else at play here, namely the camera itself. If I enlarge your second photo (by Thanakrit), the dark lunar disk is significally smaller than the sun disk, as displayed before or after the eclipse.

[Ann]

Yes, that is a possible explanation, but I wonder if there could be something else at play here, namely the camera itself. If I enlarge your second photo (by Thanakrit), the dark lunar disk is significally smaller than the sun disk, as displayed before or after the eclipse.

I don’t think so. Bear in mind that during a total solar eclipse, you can’t see the solar disk. It’s all dark. The bright thing surrounding the darkened solar disk is the corona.

Ann

[Lasse H]

The dark spot is too small.
At the time of the eclipse, the angular distance between Venus and Jupiter was about 45 degrees.
I enlarged the photo on my screen until the distance was 45 centimeters. At that scale the sun/moon disk should be half a centimeter in diameter (5 millimeters), but the dark spot was only about 2 millimeters wide!

My tentative explanation is that the bright corona light "eats up" some part of the rim of the dark disk somehow. What I mean is that this happens in the camera optics or on the optoelectronic chip itself. Alternatively because you cannot keep the camera completely still during the exposure.

[Chris Peterson]

The dark spot is too small.
At the time of the eclipse, the angular distance between Venus and Jupiter was about 45 degrees.
I enlarged the photo on my screen until the distance was 45 centimeters. At that scale the sun/moon disk should be half a centimeter in diameter (5 millimeters), but the dark spot was only about 2 millimeters wide!

My tentative explanation is that the bright corona light "eats up" some part of the rim of the dark disk somehow. What I mean is that this happens in the camera optics or on the optoelectronic chip itself. Alternatively because you cannot keep the camera completely still during the exposure.

The image is overexposed for the corona, which means its light is bleeding into the silhouette of the Moon. So you can't take any reasonable measurements from the image. Here's a very similar image I made, just with my phone during totality. Of course, I had other instruments on it at the same time which produced images where all the exposures were correct, and those do show the eclipse geometry very accurately. To do that with an image like that would require multiple exposures and careful HDR processing.

(Very interesting to me in comparing these images are the two radial spikes in the corona pointing generally away from Venus. I had assumed in my image this was simply scatter in the optics, but now seeing the same structures in today's APOD, it's clear they are real. Presumably caused by overexposed prominences in those locations. Neat.)
_

[Lasse H]

What you write ("bleeding into...") is exactly what I meant. The dark spot in the center (the Moon) looks smaller in the picture than it is in real life.

[wilddouglascounty]

This conversation about digital processing and imagery differences shrinking or enlarging high contrast components of an image brings to mind my experience of the eclipse only a few miles away from where this photo was taken.

The eye, occipital lobe visual processing part of the brain and other processing centers do a much more refined image generation than digital imaging is capable of doing, and viewing an eclipse really brings out these differences. The brain is incredible in creating a continuum of brightness, for instance, compared to digital images. The orange-yellow prominence located at the 5 o'clock position during totality, for instance, was hugely more prominent in person than any digital image that I've seen, due to the eye being able to process the incredible difference between the dark disk of the moon, the surrounding dark sky, and the brightness of the prominence, much better than digital processing, which just maxed it out as a depiction of white over-exposure or dimmed everything else down to where you could see the colors of the prominence.

As the moon approached totality, the eye also depicted the moon as having more of a 3 dimensionality to the moon; an illusion of course, but nevertheless a palpable sensation that is lost in all digital imagery. Finally, when the moon was exiting the sun's disk and the Bailey's bead/diamond ring spread to a wider, brighter arc, the beam of light that shone down through the darkness of the surrounding darkened landscape was like a giant spotlight shooting down from the sun to the ground. Perhaps it was the same artifact that created super sharp shadows around totality, but once again, the firsthand experience of this super-focused beam of light shooting down to the ground in the surrounding darkness was something that no digital depiction that I've seen has come close to capturing.

Cameras shooting images of the milky way make me wish I could see the clouds and dust lanes as clearly as they do, but then I see the eclipse and realize that the eye and brain still have way more processing power than that little CCD behind the lens.

[Chris Peterson]

This conversation about digital processing and imagery differences shrinking or enlarging high contrast components of an image brings to mind my experience of the eclipse only a few miles away from where this photo was taken.

The eye, occipital lobe visual processing part of the brain and other processing centers do a much more refined image generation than digital imaging is capable of doing, and viewing an eclipse really brings out these differences. The brain is incredible in creating a continuum of brightness, for instance, compared to digital images. The orange-yellow prominence located at the 5 o'clock position during totality, for instance, was hugely more prominent in person than any digital image that I've seen, due to the eye being able to process the incredible difference between the dark disk of the moon, the surrounding dark sky, and the brightness of the prominence, much better than digital processing, which just maxed it out as a depiction of white over-exposure or dimmed everything else down to where you could see the colors of the prominence.

As the moon approached totality, the eye also depicted the moon as having more of a 3 dimensionality to the moon; an illusion of course, but nevertheless a palpable sensation that is lost in all digital imagery. Finally, when the moon was exiting the sun's disk and the Bailey's bead/diamond ring spread to a wider, brighter arc, the beam of light that shone down through the darkness of the surrounding darkened landscape was like a giant spotlight shooting down from the sun to the ground. Perhaps it was the same artifact that created super sharp shadows around totality, but once again, the firsthand experience of this super-focused beam of light shooting down to the ground in the surrounding darkness was something that no digital depiction that I've seen has come close to capturing.

Cameras shooting images of the milky way make me wish I could see the clouds and dust lanes as clearly as they do, but then I see the eclipse and realize that the eye and brain still have way more processing power than that little CCD behind the lens.

I disagree. I've seen a number of eclipses, and while images can't capture the overall ambience and awe that go with that experience, they blow away the human eye and brain for capturing detail and dynamic range. A good camera, good optics, and good processing far, far exceed what our senses are capable of seeing. Much greater dynamic range, much higher resolution. Our visual system is pretty pathetic compared with digital imaging and processing.

[johnnydeep]

This conversation about digital processing and imagery differences shrinking or enlarging high contrast components of an image brings to mind my experience of the eclipse only a few miles away from where this photo was taken.

The eye, occipital lobe visual processing part of the brain and other processing centers do a much more refined image generation than digital imaging is capable of doing, and viewing an eclipse really brings out these differences. The brain is incredible in creating a continuum of brightness, for instance, compared to digital images. The orange-yellow prominence located at the 5 o'clock position during totality, for instance, was hugely more prominent in person than any digital image that I've seen, due to the eye being able to process the incredible difference between the dark disk of the moon, the surrounding dark sky, and the brightness of the prominence, much better than digital processing, which just maxed it out as a depiction of white over-exposure or dimmed everything else down to where you could see the colors of the prominence.

As the moon approached totality, the eye also depicted the moon as having more of a 3 dimensionality to the moon; an illusion of course, but nevertheless a palpable sensation that is lost in all digital imagery. Finally, when the moon was exiting the sun's disk and the Bailey's bead/diamond ring spread to a wider, brighter arc, the beam of light that shone down through the darkness of the surrounding darkened landscape was like a giant spotlight shooting down from the sun to the ground. Perhaps it was the same artifact that created super sharp shadows around totality, but once again, the firsthand experience of this super-focused beam of light shooting down to the ground in the surrounding darkness was something that no digital depiction that I've seen has come close to capturing.

Cameras shooting images of the milky way make me wish I could see the clouds and dust lanes as clearly as they do, but then I see the eclipse and realize that the eye and brain still have way more processing power than that little CCD behind the lens.

I disagree. I've seen a number of eclipses, and while images can't capture the overall ambience and awe that go with that experience, they blow away the human eye and brain for capturing detail and dynamic range. A good camera, good optics, and good processing far, far exceed what our senses are capable of seeing. Much greater dynamic range, much higher resolution. Our visual system is pretty pathetic compared with digital imaging and processing.

Aw, Chris - always the reality-based party pooper.

[Chris Peterson]

This conversation about digital processing and imagery differences shrinking or enlarging high contrast components of an image brings to mind my experience of the eclipse only a few miles away from where this photo was taken.

The eye, occipital lobe visual processing part of the brain and other processing centers do a much more refined image generation than digital imaging is capable of doing, and viewing an eclipse really brings out these differences. The brain is incredible in creating a continuum of brightness, for instance, compared to digital images. The orange-yellow prominence located at the 5 o'clock position during totality, for instance, was hugely more prominent in person than any digital image that I've seen, due to the eye being able to process the incredible difference between the dark disk of the moon, the surrounding dark sky, and the brightness of the prominence, much better than digital processing, which just maxed it out as a depiction of white over-exposure or dimmed everything else down to where you could see the colors of the prominence.

As the moon approached totality, the eye also depicted the moon as having more of a 3 dimensionality to the moon; an illusion of course, but nevertheless a palpable sensation that is lost in all digital imagery. Finally, when the moon was exiting the sun's disk and the Bailey's bead/diamond ring spread to a wider, brighter arc, the beam of light that shone down through the darkness of the surrounding darkened landscape was like a giant spotlight shooting down from the sun to the ground. Perhaps it was the same artifact that created super sharp shadows around totality, but once again, the firsthand experience of this super-focused beam of light shooting down to the ground in the surrounding darkness was something that no digital depiction that I've seen has come close to capturing.

Cameras shooting images of the milky way make me wish I could see the clouds and dust lanes as clearly as they do, but then I see the eclipse and realize that the eye and brain still have way more processing power than that little CCD behind the lens.

I disagree. I've seen a number of eclipses, and while images can't capture the overall ambience and awe that go with that experience, they blow away the human eye and brain for capturing detail and dynamic range. A good camera, good optics, and good processing far, far exceed what our senses are capable of seeing. Much greater dynamic range, much higher resolution. Our visual system is pretty pathetic compared with digital imaging and processing.

Aw, Chris - always the reality-based party pooper.

But the other side of the coin... we have a great big brain that lets us dramatically extend our senses with complex technology.

[johnnydeep]

I disagree. I've seen a number of eclipses, and while images can't capture the overall ambience and awe that go with that experience, they blow away the human eye and brain for capturing detail and dynamic range. A good camera, good optics, and good processing far, far exceed what our senses are capable of seeing. Much greater dynamic range, much higher resolution. Our visual system is pretty pathetic compared with digital imaging and processing.

Aw, Chris - always the reality-based party pooper.

But the other side of the coin... we have a great big brain that lets us dramatically extend our senses with complex technology.

Yes, we can at least be comforted in that!