APOD: Cathedral, Mountain, Moon (2023 Dec 25)

[APOD Robot]

Cathedral, Mountain, Moon

Explanation: Single shots like this require planning. The first step is to realize that such an amazing triple-alignment actually takes place. The second step is to find the best location to photograph it. But it was the third step: being there at exactly the right time -- and when the sky was clear -- that was the hardest. Five times over six years the photographer tried and found bad weather. Finally, just ten days ago, the weather was perfect, and a photographic dream was realized. Taken in Piemonte, Italy, the cathedral in the foreground is the Basilica of Superga, the mountain in the middle is Monviso, and, well, you know which moon is in the background. Here, even though the setting Moon was captured in a crescent phase, the exposure was long enough for doubly reflected Earthlight, called the da Vinci glow, to illuminate the entire top of the Moon.

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[FLPhotoCatcher]

Wow, great photo!

[Stanislaw Lem]

Remarkable photo.

But the Basilica of Superga is not a cathedral; not all big old churches are cathedrals. Cathedrals are bishop's seats; Superga is a basilica, a specific designation distinct from cathedral.

Incorrectly referring to Superga as a "cathedral" is like calling Venus a "star." There may be a superficial apparent resemblance but they are quite different things.

https://en.wikipedia.org/wiki/Basilica_of_Superga
https://en.wikipedia.org/wiki/Cathedral
https://en.wikipedia.org/wiki/Basilicas ... lic_Church

[Whiskybreath]

Outstanding photograph.

[VictorBorun]

kid's question: why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it?

MoonAligned_Minato_2974-3.jpg (15.11 KiB) Viewed 10364 times

MoonAligned_Minato_2974-.jpg (36.68 KiB) Viewed 10195 times

[richard_schumacher]

why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it?

Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so.

[VictorBorun]

why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it?

Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so.

(playing the kid who could have asked the kid's question)
I take it you assume that the light scattered is not coming from Moon (and this must be so seeing the shine is blue rather than red) and can not be obscured by Monviso.
But how come that the sky near Moon is shining with scattered photons directly from Sun?
A typical moonlit night's sky is shining with scattered photons from Moon, isn't it?

[Guest again]

An exceptional photograph!
But you would think he could have at least waited for a partial lunar eclipse to begin too?

[Chris Peterson]

why the dark blue shine of the night sky looks almost the same in front of Monviso and beside it?

Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so.

(playing the kid who could have asked the kid's question)
I take it you assume that the light scattered is not coming from Moon (and this must be so seeing the shine is blue rather than red) and can not be obscured by Monviso.
But how come that the sky near Moon is shining with scattered photons directly from Sun?
A typical moonlit night's sky is shining with scattered photons from Moon, isn't it?

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light.

I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR processing, so it's hard to assess the actual relative brightnesses of different parts.

[VictorBorun]

Distance. Monviso is far enough from the camera that the air scatter (chiaroscuro) between them is saturated, or nearly so.

(playing the kid who could have asked the kid's question)
I take it you assume that the light scattered is not coming from Moon (and this must be so seeing the shine is blue rather than red) and can not be obscured by Monviso.
But how come that the sky near Moon is shining with scattered photons directly from Sun?
A typical moonlit night's sky is shining with scattered photons from Moon, isn't it?

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light.

I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR processing, so it's hard to assess the actual relative brightnesses of different parts.

out of astronomical twilight? And where are the stars?

Moon's disk does look like illuminated by 10% of diameter along the axis of the crescent's symmetry and the axis is tilted by 30°
cos 37°= 0.8, so an angular distance of 37°seems probable between Sun's and Moon's disks
The 30° tilt makes the vertical angular distance 37°/2 = 18.5°
If Moon's disk is 2° above the horizon, then Sun's must be 16.5° below, mustn't it?

[VictorBorun]

looked up
1) date and time = December 15, 2023 at 18:52 pm
2) stellarium

...

Click to view full size image 1 or image 2

Moon is 9° above (+09°01'15.1") and Phase=9%, Sun is 11° below (-10°55'12.6")
Twilight it is

[Chris Peterson]

(playing the kid who could have asked the kid's question)
I take it you assume that the light scattered is not coming from Moon (and this must be so seeing the shine is blue rather than red) and can not be obscured by Monviso.
But how come that the sky near Moon is shining with scattered photons directly from Sun?
A typical moonlit night's sky is shining with scattered photons from Moon, isn't it?

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light.

I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR processing, so it's hard to assess the actual relative brightnesses of different parts.

out of astronomical twilight? And where are the stars?

Moon's disk does look like illuminated by 10% of diameter along the axis of the crescent's symmetry and the axis is tilted by 30°
cos 37°= 0.8, so an angular distance of 37°seems probable between Sun's and Moon's disks
The 30° tilt makes the vertical angular distance 37°/2 = 18.5°
If Moon's disk is 2° above the horizon, then Sun's must be 16.5° below, mustn't it?
MoonAligned_Minato_2974-5.jpg

Double checked the ephemeris. Taking the location as Turin (because it's in the list, and only a few miles away), 15 Dec 2023, 18:52 local, I get the Moon at 2° above the horizon, the Sun at 21° below the horizon, Moon at 10% waxing.

[VictorBorun]

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light.

I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR processing, so it's hard to assess the actual relative brightnesses of different parts.

out of astronomical twilight? And where are the stars?

Moon's disk does look like illuminated by 10% of diameter along the axis of the crescent's symmetry and the axis is tilted by 30°
cos 37°= 0.8, so an angular distance of 37°seems probable between Sun's and Moon's disks
The 30° tilt makes the vertical angular distance 37°/2 = 18.5°
If Moon's disk is 2° above the horizon, then Sun's must be 16.5° below, mustn't it?
MoonAligned_Minato_2974-5.jpg

Double checked the ephemeris. Taking the location as Turin (because it's in the list, and only a few miles away), 15 Dec 2023, 18:52 local, I get the Moon at 2° above the horizon, the Sun at 21° below the horizon, Moon at 10% waxing.

I am feeling lost. Is Stellarium so unprecise? Is using "local time" half an hour off the time zone?

[VictorBorun]

This is a 10% Moon that is 2° above the horizon. The Sun is 21° below the horizon, so just out of astronomical twilight and it should not be contributing significant light.

I would be curious to know the technical details of the image. I don't think it could be achieved without some kind of HDR processing, so it's hard to assess the actual relative brightnesses of different parts.

out of astronomical twilight? And where are the stars?

Moon's disk does look like illuminated by 10% of diameter along the axis of the crescent's symmetry and the axis is tilted by 30°
cos 37°= 0.8, so an angular distance of 37°seems probable between Sun's and Moon's disks
The 30° tilt makes the vertical angular distance 37°/2 = 18.5°
If Moon's disk is 2° above the horizon, then Sun's must be 16.5° below, mustn't it?
MoonAligned_Minato_2974-5.jpg

Double checked the ephemeris. Taking the location as Turin (because it's in the list, and only a few miles away), 15 Dec 2023, 18:52 local, I get the Moon at 2° above the horizon, the Sun at 21° below the horizon, Moon at 10% waxing.

it's the time difference of 1 hour: 20:52

Moon's Altitude = +02°17'18.4", Phase = 10%
Sun's Altitude = -21°01'18.9"

Вut which hour it was in fact, twilight or night?

[Chris Peterson]

out of astronomical twilight? And where are the stars?

Moon's disk does look like illuminated by 10% of diameter along the axis of the crescent's symmetry and the axis is tilted by 30°
cos 37°= 0.8, so an angular distance of 37°seems probable between Sun's and Moon's disks
The 30° tilt makes the vertical angular distance 37°/2 = 18.5°
If Moon's disk is 2° above the horizon, then Sun's must be 16.5° below, mustn't it?
MoonAligned_Minato_2974-5.jpg

Double checked the ephemeris. Taking the location as Turin (because it's in the list, and only a few miles away), 15 Dec 2023, 18:52 local, I get the Moon at 2° above the horizon, the Sun at 21° below the horizon, Moon at 10% waxing.

I am feeling lost. Is Stellarium so unprecise? Is using "local time" half an hour off the time zone?

I'm assuming that the imager's stated time of 18:52 is his local time, CST (or 17:52 UT), which is what I'm basing my calculation on.

FWIW, the mountain is 70 km from the basilica, and about 3000 m higher. So there's no way at all the Moon could be 9° above the horizon.

[VictorBorun]

Double checked the ephemeris. Taking the location as Turin (because it's in the list, and only a few miles away), 15 Dec 2023, 18:52 local, I get the Moon at 2° above the horizon, the Sun at 21° below the horizon, Moon at 10% waxing.

I am feeling lost. Is Stellarium so unprecise? Is using "local time" half an hour off the time zone?

I'm assuming that the imager's stated time of 18:52 is his local time, CST (or 17:52 UT), which is what I'm basing my calculation on.

FWIW, the mountain is 70 km from the basilica, and about 3000 m higher. So there's no way at all the Moon could be 9° above the horizon.

3 km / 70 km = tg 2.5°
ok, the hour is set and night it is.
Where are the stars?
Why the blue shine is of the same brightness in front of and beside the mountain? (Except close to the crescent, where the orange shine prevails)

[Chris Peterson]

I am feeling lost. Is Stellarium so unprecise? Is using "local time" half an hour off the time zone?

I'm assuming that the imager's stated time of 18:52 is his local time, CST (or 17:52 UT), which is what I'm basing my calculation on.

FWIW, the mountain is 70 km from the basilica, and about 3000 m higher. So there's no way at all the Moon could be 9° above the horizon.

3 km / 70 km = tg 2.5°
ok, the hour is set and night it is.
Where are the stars?
Why the blue shine is of the same brightness in front of and beside the mountain? (Except close to the crescent, where the orange shine prevails)

It does not surprise me that the sky is the same everywhere. Certainly, under all but the most clear of conditions, most of the scatter will be within that 70 km slice between the basilica and the mountain. In the day, the mountain might barely be visible, all but lost in atmospheric scatter.

There may be a couple of stars visible just above the Moon. I can't match them reliably to anything on my charts, though. Or rather, I can, but if they were those objects, we ought to see other brighter ones also. So I'm not sure what's going on with the blue sky and absence of stars. Again, we really need more detail on how the image was made and processed.

[VictorBorun]

after subtracting the blue shine (rgb = 45 64 91) there are some stars in the sky, probably not visible without a telescope

[Chris Peterson]

after subtracting the blue shine (rgb = 45 64 91) there are some stars in the sky, probably not visible without a telescope
Cathedral, Mountain, Moon-black.jpg

I think the near total absence of stars is largely explained because we are looking through hundreds of kilometers of atmosphere within just a few degrees of the horizon. And maybe not the clearest atmosphere, at that.

[VictorBorun]

after subtracting the blue shine (rgb = 45 64 91) there are some stars in the sky, probably not visible without a telescope
Cathedral, Mountain, Moon-black.jpg

I think the near total absence of stars is largely explained because we are looking through hundreds of kilometers of atmosphere within just a few degrees of the horizon. And maybe not the clearest atmosphere, at that.

70 km up to Monteviso is much clearer than say 350 km behind it to judge from the sharp mountain's edge versus Moon's blurred features

[VictorBorun]

I'm assuming that the imager's stated time of 18:52 is his local time, CST (or 17:52 UT), which is what I'm basing my calculation on.

FWIW, the mountain is 70 km from the basilica, and about 3000 m higher. So there's no way at all the Moon could be 9° above the horizon.

3 km / 70 km = tg 2.5°
ok, the hour is set and night it is.
Where are the stars?
Why the blue shine is of the same brightness in front of and beside the mountain? (Except close to the crescent, where the orange shine prevails)

It does not surprise me that the sky is the same everywhere. Certainly, under all but the most clear of conditions, most of the scatter will be within that 70 km slice between the basilica and the mountain. In the day, the mountain might barely be visible, all but lost in atmospheric scatter.

There may be a couple of stars visible just above the Moon. I can't match them reliably to anything on my charts, though. Or rather, I can, but if they were those objects, we ought to see other brighter ones also. So I'm not sure what's going on with the blue sky and absence of stars. Again, we really need more detail on how the image was made and processed.

I am trying to guess the 2 stars like this.
1) switch off the atmosphere in Stellarium
2) subtract the blue shine and stretch this APOD till the disk of Moon is round to roughly correct the atmosphere lensing
3) fit a screenshot of Stellarium page to the stretched APOD

Voila, there are two brightest stars in right places!

The bright orange one at right is BD Capricorni, Magnitude=7.53, Spectral Type = A9III
The blinking one at left is HD 191501, Magnitude=9.13, Spectral Type=A2

...

Click to view full size image 1 or image 2

[MarkBour]

Wow, great photo!

I agree, what an amazing image! It would not have been as great had Valerio Minato simply "happened" onto it. But to have planned it and had to return many times until this perfect capture, is so impressive and satisfying.

I think the light that is the Earthshine that lights the bulk of the Moon's disk here is different than the Earthshine one sees during a lunar eclipse. The latter, I believe, is from rays of sunlight that pass through Earth's atmosphere and -- slightly refracted -- head more directly to the surface of the Moon and then back to our eyes and cameras. The former, however, which we see in this image, first hits the Earth, mostly on places that are still in daylight, then reflects to the Moon, and finally bounces off its surface back to our eyes and cameras. This latter Earthshine, therefore, is a little bit different. It arrives at the Moon's surface about 1.3 seconds later* than the light that is directly illuminating the bright crescent. Not a big difference between the two kinds of Earthshine, just reflected rather than refracted on the journey.

I suppose some photon might have hit the Earth, reflected to the Moon, reflected to the backside of Monviso, reflected back to the Moon, and finally reflected back into the camera lens. At least a large number of photons made the first 3 legs of this journey, which is the whole reason you can see the silhouette of the mountain.

* (By "later", I'm just referring to photons that left the Sun at the same instant.)

[nikkam]

I live in Turin (Torino) where Superga's Basilica is; only one who does not live in Turin can be supposed to think that this shot is true; it's only a tremendous fake.

[alter-ego]

I live in Turin (Torino) where Superga's Basilica is; only one who does not live in Turin can be supposed to think that this shot is true; it's only a tremendous fake.

So why do you think that?

[EmanueleBalboni]

I live in Turin (Torino) where Superga's Basilica is; only one who does not live in Turin can be supposed to think that this shot is true; it's only a tremendous fake.

I also live in Turin, and not knowing the place from which you can see the alignment does not allow you to say this shot is fake. Listen my advice: take a walk/ride/drive towards Castagneto Po in a beautiful day and see for yourself