Is the brightness of saturn realistic?
Saturn Conjunction 2005 (903 KB):
Full Version: Saturn Grazing The Sun
Here's a small simulation of the last close conjunction of sun and saturn.
Is the brightness of saturn realistic?
Saturn Conjunction 2005 (903 KB):
Is the brightness of saturn realistic?
Saturn Conjunction 2005 (903 KB):
No.
Simple answer - the image format you are using does not support a high enough dynamic range to show something like this in any way that is meaningfully realistic.
The apparent magnitude of the sun is -26.73, that of Saturn 0.7. That means that the sun appears to be 2.512^(0.7 - (-26.73)) == ~94 billion times brigter than saturn.
That brightness is the sum of the average intensity over the entire area of the objects so..
The difference in apparent area between the two is around 5000.
The average intensity of each pixel of Saturn needs to be around 19 million times fainter than the sun (in absolute terms).
That could just about be represented with a 24 bit gray scale image format but it could be represented by a floating point image format (TIFF being the obvious one).
However since the human eye under optimal conditions can only handle about 14 F/stops (10 Magnitudes) of dynamic range concurrently there is no way you could ever see both at the same time no matter how you try to do it and any representation showing both the solar disk and saturn has to be unrealistic for us to see both.
Simple answer - the image format you are using does not support a high enough dynamic range to show something like this in any way that is meaningfully realistic.
The apparent magnitude of the sun is -26.73, that of Saturn 0.7. That means that the sun appears to be 2.512^(0.7 - (-26.73)) == ~94 billion times brigter than saturn.
That brightness is the sum of the average intensity over the entire area of the objects so..
The difference in apparent area between the two is around 5000.
The average intensity of each pixel of Saturn needs to be around 19 million times fainter than the sun (in absolute terms).
That could just about be represented with a 24 bit gray scale image format but it could be represented by a floating point image format (TIFF being the obvious one).
However since the human eye under optimal conditions can only handle about 14 F/stops (10 Magnitudes) of dynamic range concurrently there is no way you could ever see both at the same time no matter how you try to do it and any representation showing both the solar disk and saturn has to be unrealistic for us to see both.
On the other hand, Saturn obscuring the Sun would look pretty spectacular. Too bad there is not way to see it from Earth, and I don't think Cassini can point its camera towards the Sun (without damage risk, that is).
Almost any shot of the body of Saturn eclipsing the sun would be cool but its going to be a very long time before we see any other than those (amazing) shots taken by Cassini.
It may be obvious to the astronomy types but I found it interesting that when you try to setup a transit to compare with SigurRosFan's almost occultation shot that you have to go very far away indeed. Celestia choked at reducing the FOV below 3.4" of arc so this was as close as I could get.
Click to view attachment
It may be obvious to the astronomy types but I found it interesting that when you try to setup a transit to compare with SigurRosFan's almost occultation shot that you have to go very far away indeed. Celestia choked at reducing the FOV below 3.4" of arc so this was as close as I could get.
Click to view attachment
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