Starship Asterisk*

[quote=paumontplet post_id=341006 time=1724965040 user_id=147290]
[quote=Ann post_id=340974 time=1724733374 user_id=129702]
Yes, that's a nice APOD! :D


[img3="Moon Eclipses Saturn.
Image Credit & Copyright: Pau Montplet Sanz"]https://apod.nasa.gov/apod/image/2408/MoonEclipsesSaturn_Sanz_960.jpg[/img3]


But I have a few questions:

1) Why is Saturn so very "strongly striped"? Only Jupiter is that striped, right?

2) Why is Saturn so colorful? It colors range from yellow-white to yellowish ochre to dark tan to peach to bluish gray. Saturn isn't usually that colorful.

3) Why isn't Saturn brighter compared with the Moon? The albedo (reflectivity) of Saturn is considerably higher than the albedo of the Moon. Is it because Saturn is so much farther away from the Sun compared with the Moon, so that there is less sunlight for Saturn to reflect?

Let's look at a May 2024 picture of Saturn:


[img3="Saturn on May 2, 2024. Credit: Ittaku of Cloudy Nights."]https://www.cloudynights.com/uploads/gallery/album_14358/gallery_338887_14358_94287.jpg[/img3]

Ann
[/quote]

Hello Ann, I'm the author of this image (APOD)

Yes, Saturn has many stripes. although less contrasted than Jupiter.

The Saturn that you sent is a little off in color, this planet is not brown. Okay, maybe not as colorful as mine either, it only has saturated colors and the blue tones lowered a little so that that pretty color comes out. I send my best image of this planet: [img]https://i.postimg.cc/fRcCTjKs/2024-08-12-0234-2-U-RGB-Sat-lapl6-ap329.png[/img]
[/quote]

Thank you for your reply to me, Pau Montplet! :D

I am very well aware that deep sky objects look different in different images, due to different photographers' equipment, seeing, exposure time, position of the object in the sky, and, not least, the processing of the image.

I have indeed seen other images of Saturn where the planet looks strongly striped. However, most Saturn images don't look like that.

I have also seen a very few images where Saturn looks very colorful. I particularly remember a blatantly false color Voyager 1 image:


[float=right][img3="Another version of Voyager 1's false color Saturn."]https://imgix.bustle.com/uploads/getty/2022/8/31/45e37304-ad97-445f-af99-6f06c76ec96e-getty-915226328.jpg?w=825&h=740&fit=crop&crop=faces[/img3][/float][img3="False color image of Saturn by Voyager 1."]https://science.nasa.gov/wp-content/uploads/2024/04/pia03152.jpg?w=849[/img3]
[clear][/clear]


I remember being angry at the Voyager 1 false color images of Saturn, because I thought that NASA was lying to me! But the main reason for painting Saturn in such glaring colors was undoubtedly to bring out the stripes of the planet's atmosphere, which are mostly hidden under a layer of haze.

Most pictures of Saturn show the sixth planet of the solar system as mostly pale yellow in color. If you take a look at the [url=https://en.wikipedia.org/wiki/Saturn]Wikipedia[/url] entry on Saturn, all seven color pictures of the planets there are more yellow and less blue than yours.

But I did find one image that somewhat matches yours, and it is described as natural color, too:


[img3="Saturn, Titan, ring plane and ring shadows. Credit: NASA/JPL-Caltech/SSI"]https://scitechdaily.com/images/Cassini-Spacecraft-Conducts-Its-100th-Flyby-of-the-Saturn-Moon-Titan-777x727.jpg[/img3]


Ann

[quote=Ann post_id=340974 time=1724733374 user_id=129702]
Yes, that's a nice APOD! :D


[img3="Moon Eclipses Saturn.
Image Credit & Copyright: Pau Montplet Sanz"]https://apod.nasa.gov/apod/image/2408/MoonEclipsesSaturn_Sanz_960.jpg[/img3]


But I have a few questions:

1) Why is Saturn so very "strongly striped"? Only Jupiter is that striped, right?

2) Why is Saturn so colorful? It colors range from yellow-white to yellowish ochre to dark tan to peach to bluish gray. Saturn isn't usually that colorful.

3) Why isn't Saturn brighter compared with the Moon? The albedo (reflectivity) of Saturn is considerably higher than the albedo of the Moon. Is it because Saturn is so much farther away from the Sun compared with the Moon, so that there is less sunlight for Saturn to reflect?

Let's look at a May 2024 picture of Saturn:


[img3="Saturn on May 2, 2024. Credit: Ittaku of Cloudy Nights."]https://www.cloudynights.com/uploads/gallery/album_14358/gallery_338887_14358_94287.jpg[/img3]

Ann
[/quote]

Hello Ann, I'm the author of this image (APOD)

Yes, Saturn has many stripes. although less contrasted than Jupiter.

The Saturn that you sent is a little off in color, this planet is not brown. Okay, maybe not as colorful as mine either, it only has saturated colors and the blue tones lowered a little so that that pretty color comes out. I send my best image of this planet: [img]https://i.postimg.cc/fRcCTjKs/2024-08-12-0234-2-U-RGB-Sat-lapl6-ap329.png[/img]

[quote="APOD Robot" post_id=340972 time=1724731660 user_id=128559]
Eclipses of Saturn by [url=https://science.nasa.gov/moon/]our Moon[/url] will occur each month for the rest of this year. Each time, though, the fleeting event will be visible only to those with clear skies -- and the right location on [url=https://apod.nasa.gov/apod/ap220206.html]Earth[/url].
[/quote]

For those looking for those right locations:
[img2]http://www.lunar-occultations.com/iota/planets/saturn.png[/img2]
(Can't speak to the clear skies, though)

[quote=Ann post_id=340974 time=1724733374 user_id=129702]
3) Why isn't Saturn brighter compared with the Moon? The albedo (reflectivity) of Saturn is considerably higher than the albedo of the Moon. Is it because Saturn is so much farther away from the Sun compared with the Moon, so that there is less sunlight for Saturn to reflect?
[/quote]

Yes, it's because Saturn is more distant from the Sun (the light source) and the Earth.

"Sunlight on Saturn is significantly dimmer than on Earth due to the vast difference in distance from the Sun. Saturn is about 9.5 astronomical units (AU) from the Sun, meaning it is 9.5 times farther from the Sun than Earth is. According to the inverse square law, the intensity of sunlight decreases with the square of the distance from the source.

On Earth, the solar constant (the amount of solar energy received per square meter) is about 1366 watts per square meter. On Saturn, this value drops to approximately 1% of what Earth receives, which is around 15 watts per square meter.

This means that sunlight on Saturn is roughly 100 times dimmer than on Earth. Despite this, Saturn’s high albedo (reflectivity) helps it remain visible from Earth."

[quote=Ann post_id=340974 time=1724733374 user_id=129702]
Yes, that's a nice APOD! :D


[img3="Moon Eclipses Saturn.
Image Credit & Copyright: Pau Montplet Sanz"]https://apod.nasa.gov/apod/image/2408/MoonEclipsesSaturn_Sanz_960.jpg[/img3]


But I have a few questions:

1) Why is Saturn so very "strongly striped"? Only Jupiter is that striped, right?

2) Why is Saturn so colorful? It colors range from yellow-white to yellowish ochre to dark tan to peach to bluish gray. Saturn isn't usually that colorful.

3) Why isn't Saturn brighter compared with the Moon? The albedo (reflectivity) of Saturn is considerably higher than the albedo of the Moon. Is it because Saturn is so much farther away from the Sun compared with the Moon, so that there is less sunlight for Saturn to reflect?

Let's look at a May 2024 picture of Saturn:


[img3="Saturn on May 2, 2024. Credit: Ittaku of Cloudy Nights."]https://www.cloudynights.com/uploads/gallery/album_14358/gallery_338887_14358_94287.jpg[/img3]

Ann
[/quote]


"The featured color image is a digital fusion of the clearest images captured during the event and rebalanced for color and relative brightness between the relatively dim Saturn and the comparatively bright Moon."

[url]https://www.instagram.com/p/C-8M5VuS_2o/[/url]

Yes, that's a nice APOD! :D


[img3="Moon Eclipses Saturn.
Image Credit & Copyright: Pau Montplet Sanz"]https://apod.nasa.gov/apod/image/2408/MoonEclipsesSaturn_Sanz_960.jpg[/img3]


But I have a few questions:

1) Why is Saturn so very "strongly striped"? Only Jupiter is that striped, right?

2) Why is Saturn so colorful? It colors range from yellow-white to yellowish ochre to dark tan to peach to bluish gray. Saturn isn't usually that colorful.

3) Why isn't Saturn brighter compared with the Moon? The albedo (reflectivity) of Saturn is considerably higher than the albedo of the Moon. Is it because Saturn is so much farther away from the Sun compared with the Moon, so that there is less sunlight for Saturn to reflect?

Let's look at a May 2024 picture of Saturn:


[img3="Saturn on May 2, 2024. Credit: Ittaku of Cloudy Nights."]https://www.cloudynights.com/uploads/gallery/album_14358/gallery_338887_14358_94287.jpg[/img3]

Ann

[url=https://apod.nasa.gov/apod/ap240827.html] [img]https://apod.nasa.gov/apod/calendar/S_240827.jpg[/img] [size=150]Moon Eclipses Saturn[/size][/url]

[b] Explanation: [/b] What if Saturn disappeared? Sometimes, it does. It doesn't really go away, though, it just disappears from view when our [url=https://www.youtube.com/watch?v=8AtMXEviIa0]Moon moves in front[/url]. Such a Saturnian eclipse, more formally called an [url=https://en.wikipedia.org/wiki/Occultation]occultation[/url], was visible along a [url=https://in-the-sky.org/news.php?id=20240821_16_100]long swath of Earth[/url] -- from [url=https://en.wikipedia.org/wiki/Peru]Peru[/url], across the Atlantic Ocean, to [url=https://en.wikipedia.org/wiki/Italy]Italy[/url] -- only a few days ago. The [url=https://www.flickr.com/photos/astrobreda/53938042146/in/pool-apods/]featured color image[/url] is a digital fusion of the clearest images captured during [url=https://www.instagram.com/p/C-8M5VuS_2o/]the event[/url] and rebalanced for color and relative brightness between the relatively dim Saturn and the comparatively bright Moon. [url=https://science.nasa.gov/saturn/]Saturn[/url] and the [url=https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fxr8mg5nunzj91.jpg]comparative bright Moon[/url]. The exposures were all taken from [url=https://youtu.be/DCv5p4nB3bw]Breda[/url], [url=https://en.wikipedia.org/wiki/Catalonia]Catalonia[/url], [url=https://en.wikipedia.org/wiki/Spain]Spain[/url], just before occultation. [url=https://apod.nasa.gov/apod/ap020222.html]Eclipses[/url] of Saturn by [url=https://science.nasa.gov/moon/]our Moon[/url] will occur each month for the rest of this year. Each time, though, the fleeting event will be visible only to those with clear skies -- and the right location on [url=https://apod.nasa.gov/apod/ap220206.html]Earth[/url].


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