APOD: Moonrays of August (2023 Aug 04)

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APOD: Moonrays of August (2023 Aug 04)

Post by APOD Robot » Fri Aug 04, 2023 4:07 am

Image Moonrays of August

Explanation: A Full Moon rose as the Sun set on August 1. Near perigee, the closest point in its almost moonthly orbit, the brighter than average lunar disk illuminated night skies around planet Earth as the second supermoon of 2023. Seen here above Ragusa, Sicily, cloud banks cast diverging shadows through the supermoonlit skies, creating dramatic lunar crepuscular rays. The next Full Moon in 2023 will also shine on an August night. Rising as the Sun sets on August 30/31, this second Full Moon in a month is known as a Blue Moon. Blue moons occur only once every 2 or 3 years because lunar phases take almost a calendar month (29.5 days) to go through a complete cycle. But August's Blue Moon will also be near perigee, the third supermoon in 2023.

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orin stepanek
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Re: APOD: Moonrays of August (2023 Aug 04)

Post by orin stepanek » Fri Aug 04, 2023 6:03 pm

GianniTumino_Moon_Rays_JPG_LOGO_1024pix.jpg
Wow! 4 super moons in 3 mo.'s; that's more than I would suspect.
They sure are neat! 8-)
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Re: APOD: Moonrays of August (2023 Aug 04)

Post by johnnydeep » Fri Aug 04, 2023 8:54 pm

Before reading the text, that sure looked like the Sun to me!

Also, I don't understand the "because" in this sentence:
Blue moons occur only once every 2 or 3 years because lunar phases take almost a calendar month (29.5 days) to go through a complete cycle.
Why would taking a month for the Moon to go through its phase cycle result in a 2-3 year span between Blue Moons? I get that they are rare, since months vary in number of days all of which are close to the 29.5 day Lunar cycle, but that particular 2-3 year rarity surely depends on the year being exactly 12 months. If it were more or fewer months, the span between Blue Moons would be different, no?

[ Never mind: answering my own question - yes, the yearly span would be different, but the monthly span would not. I should probably delete this now pointless post, but I'll leave it for posterity. ]
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Colin Oakes

Re: APOD: Moonrays of August (2023 Aug 04)

Post by Colin Oakes » Wed Aug 09, 2023 11:31 pm

Even after reading the description, I still say that's the sun. I understand what a supermoon is. The thing is, every other image I've seen of the August 4 supermoon still shows all the usual features of the lunar surface. I mean, you can still see the Mare Serenitatis, the Mare Imbrium, the Tycho and Copernicus craters, etc. -- all the usual features you're used to seeing when you look at the moon. The fact that it's a supermoon doesn't somehow make those features disappear.

But what you see in the above photo is a monochrome orb with no discernible surface features. In other words, the sun.

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Re: APOD: Moonrays of August (2023 Aug 04)

Post by Chris Peterson » Thu Aug 10, 2023 4:08 am

Colin Oakes wrote: Wed Aug 09, 2023 11:31 pm Even after reading the description, I still say that's the sun. I understand what a supermoon is. The thing is, every other image I've seen of the August 4 supermoon still shows all the usual features of the lunar surface. I mean, you can still see the Mare Serenitatis, the Mare Imbrium, the Tycho and Copernicus craters, etc. -- all the usual features you're used to seeing when you look at the moon. The fact that it's a supermoon doesn't somehow make those features disappear.

But what you see in the above photo is a monochrome orb with no discernible surface features. In other words, the sun.
There are no features visible because it is massively overexposed. If all the pixels are saturated you will only see white. Which is very common in pictures of the Moon at night exposed for the landscape and not the Moon itself.
Chris

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Ann
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Re: APOD: Moonrays of August (2023 Aug 04)

Post by Ann » Thu Aug 10, 2023 5:03 am

Colin Oakes wrote: Wed Aug 09, 2023 11:31 pm Even after reading the description, I still say that's the sun. I understand what a supermoon is. The thing is, every other image I've seen of the August 4 supermoon still shows all the usual features of the lunar surface. I mean, you can still see the Mare Serenitatis, the Mare Imbrium, the Tycho and Copernicus craters, etc. -- all the usual features you're used to seeing when you look at the moon. The fact that it's a supermoon doesn't somehow make those features disappear.

But what you see in the above photo is a monochrome orb with no discernible surface features. In other words, the sun.

I don't expect the landscape and sky to be so dark if the Sun is up... but once I didn't make that connection... :oops:


It happened many years ago. I was much younger, but certainly at least 30. I was on the bus. It was evening. It may have been October. I was seated, but a young man and a young woman were standing next to me. And suddenly the young woman said: Look at the Sun.

And I looked. And indeed, there was the Sun, large, round, bright yellow and magnificent.

And I thought, dreamily: Something is wrong. It's so dark outside. The Sun is up, but it's still so dark. The Sun must be going out. We are all going to die.

Then the young man said, That's the Moon.

And it was. I tried to hide my embarrassment. :oops:


So I'd say that, yes, the APOD does indeed show the Moon. Not the Sun. :D

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Colin Oakes

Re: APOD: Moonrays of August (2023 Aug 04)

Post by Colin Oakes » Thu Aug 10, 2023 3:38 pm

Chris Peterson wrote: Thu Aug 10, 2023 4:08 am

There are no features visible because it is massively overexposed. If all the pixels are saturated you will only see white. Which is very common in pictures of the Moon at night exposed for the landscape and not the Moon itself.
OK. I see what you're saying. And after getting some feedback from another astrophotographer, it turns out that, yes, that is the moon.

But as you point out, the technique of using a long exposure for a night-time photo that includes a landscape is more about wanting to photograph the landscape, not any of the objects in the sky. If the photographer was really after the supermoon and the accompanying crepuscular rays, he didn't need to use such a long exposure time.

Plus, it would've been nice if the original description on the APOD page had pointed out all of the long exposure stuff. Not all of us are astrophotographers, and we might need a little bit more of an explanation to understand what we're looking at.

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Re: APOD: Moonrays of August (2023 Aug 04)

Post by Chris Peterson » Thu Aug 10, 2023 3:41 pm

Colin Oakes wrote: Thu Aug 10, 2023 3:38 pm
Chris Peterson wrote: Thu Aug 10, 2023 4:08 am

There are no features visible because it is massively overexposed. If all the pixels are saturated you will only see white. Which is very common in pictures of the Moon at night exposed for the landscape and not the Moon itself.
OK. I see what you're saying. And after getting some feedback from another astrophotographer, it turns out that, yes, that is the moon.

But as you point out, the technique of using a long exposure for a night-time photo that includes a landscape is more about wanting to photograph the landscape, not any of the objects in the sky. If the photographer was really after the supermoon and the accompanying crepuscular rays, he didn't need to use such a long exposure time.

Plus, it would've been nice if the original description on the APOD page had pointed out all of the long exposure stuff. Not all of us are astrophotographers, and we might need a little bit more of an explanation to understand what we're looking at.
Without using HDR techniques, this image could not have been exposed for the Moon and still catch the crepuscular rays, clouds, or landscape. We would only see the Moon against a black or nearly black background.
Chris

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