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 Post subject: Glancing at celestia.Sci
PostPosted: Mon, 24-07-17, 20:10 GMT 
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Hi all,

while preparing the transition of celestia.Sci to public access, I happen to encounter some cute screenshots based on new features here and there. ;-) . Perhaps it's not useless if I share these now...

Throughout, the displays of solar system bodies correspond to 16k VT textures, ALL compressed with the appropriate DXT format (via my texure tools). Normalmaps are always in the dedicated dxt5nm format, which is crucial!

Moreover, the displays are based on totally stable 64bit code (Windows 7..10, MAC OS and Linux), Eigen 3.3.x etc.

Note that thanks to the DXT format the display is absolutely smooth with fps rates between 50 ..100!

For all screenshots, click on images and then hit the fullscreen key (F11 for FF)

1) Earth and MilkyWay:
Attachment:
earth_milkyWay.jpg
earth_milkyWay.jpg [ 159.95 KiB | Viewed 219 times ]


2) Irregular galaxy DDO 82 and three bright stars
Attachment:
ddo82.jpg
ddo82.jpg [ 128.73 KiB | Viewed 214 times ]


More to come;-)

Enjoy,
Fridger

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PostPosted: Wed, 16-08-17, 18:38 GMT 
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Dock Widgets' Action

Here are some hires celestia.Sci displays (16k, DXT format) of Pluto in Natural color. I have also opened the two Qt DockWidgets (Preferences & (Celestial Browser + Eclipse finder)). In fullscreen mode, they may be moved around smoothly, while in windowed mode they are located in the left and right sections of the window, respectively.

[For all screenshots, click on images and then hit the fullscreen key (F11 for FF)]

1) Fullscreen mode (1920x1080 px) with both Dockwidgets open
Note the toolbuttons appear when the cursor moves towards the bottom lines
Attachment:
Screenshot_20170816_194700.jpg
Screenshot_20170816_194700.jpg [ 430.07 KiB | Viewed 121 times ]


2) Fullscreen mode (1920x1080 px) with both Dockwidgets closed
Note the toolbuttons appear when the cursor moves towards the bottom lines
Attachment:
pluto_2_dockwidgets.jpg
pluto_2_dockwidgets.jpg [ 328.84 KiB | Viewed 121 times ]


3) Windowed mode (CelestialBrowser Dockwidget open)
Note the toolbuttons that are activated have a blue frame!
Attachment:
Screenshot_20170816_195902.jpg
Screenshot_20170816_195902.jpg [ 325.86 KiB | Viewed 121 times ]


4) Windowed mode (only Preferences Dockwidget open)
Note the toolbuttons that are activated have a blue frame!
Attachment:
Screenshot_20170816_200103.jpg
Screenshot_20170816_200103.jpg [ 282.37 KiB | Viewed 121 times ]


Finally, the blue halo of backlit Pluto using the parameters of Mie theory for Pluto's atmosphere:
Attachment:
plutos_mieatm_2_dockwidgets.jpg
plutos_mieatm_2_dockwidgets.jpg [ 83.82 KiB | Viewed 121 times ]


Enjoy,
Fridger

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PostPosted: Thu, 17-08-17, 12:53 GMT 
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Beautiful screenshots that make it even more painful waiting for a release. :)

Will high resolution textures like this be part of the standard package, or available as a separate download?

Meanwhile, I'll have to watch my own rendering of the Milky Way...


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File comment: Milky Way
MilkyWay-2_(9x15s).jpg
MilkyWay-2_(9x15s).jpg [ 4.03 MiB | Viewed 102 times ]
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PostPosted: Thu, 17-08-17, 14:02 GMT 
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schreiberste wrote:
Beautiful screenshots that make it even more painful waiting for a release. :)

Will high resolution textures like this be part of the standard package, or available as a separate download?

Thanks for the "flowers".. The Milkyway in celestia.Sci is based on Nick Risinger's famous photographic one. I have eliminated all identified stars (with some GIMP tricks) and then replaced them by the 2 million GAIA stars from celestia.Sci that Andrew has prepared. Nick R. has granted me in written form that in the resolution shown his MW results may be used in celestia.Sci. He was not willing though to grant me a higher resolution (which of course exists) ;-) .

I am not yet certain about the general texture resolution in the celestia.Sci release and thus I am still experimenting. In any case: all textures that don't forbid it by Copyright will be made available. I have recently experimented with a new 16k VT set all in high-quality DXT format, including .dxtnm (crucial!) for the Normalmaps, all in the same resolution! This set renders ultra-smoothly via the tiles and was prepared with my optimized texture tools and normalmap tools.

If I knew how to make them available in the distribution that would be my choice! 16k can still be handled pretty well in downloads yet is amazingly detailed and smooth already...and unbeatably FAST.
Quote:
Meanwhile, I'll have to watch my own rendering of the Milky Way...

Aha! Where are your MW data from? Looking very interesting.

Actually: I now remember there was another photographic MW atlas available online even in higher resolution. Unfortunately, the software used by the author for digital assembly of the individual photos was by far too inaccurate or even buggy. These data were not usable with our standards, therefore. I hope your nice image above is not related to this atlas? Did you check the Ra-Dec accuracy carefully?

Cheers,
Fridger

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PostPosted: Thu, 17-08-17, 14:38 GMT 
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t00fri wrote:
In any case: all textures that don't forbid it by Copyright will be made available. I have recently experimented with a new 16k VT set all in high-quality DXT format, including .dxtnm (crucial!) for the Normalmaps, all in the same resolution! This set renders ultra-smoothly via the tiles and was prepared with my optimized texture tools and normalmap tools.


Sounds promising :)

t00fri wrote:
Aha! Where are your MW data from? Looking very interesting.

I have to admit that this was a kind of a joke. :D
This Milky Way image is the result of stacking 9 photos I've taken in the mountains of Gran Canaria recently. As long as I don't have celestia.Sci to play with, I spend my time with some astro photography.
So I guess, the data should be pretty accurate, but maybe the mapping is not perfect because of lens distortion, and the color rendition might be totally artistic :D


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PostPosted: Thu, 17-08-17, 14:51 GMT 
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schreiberste wrote:
t00fri wrote:
Aha! Where are your MW data from? Looking very interesting.

I have to admit that this was a kind of a joke. :D
This Milky Way image is the result of stacking 9 photos I've taken in the mountains of Gran Canaria recently. As long as I don't have celestia.Sci to play with, I spend my time with some astro photography.
So I guess, the data should be pretty accurate, but maybe the mapping is not perfect because of lens distortion, and the color rendition might be totally artistic :D

Nice! Actually that's how our famous MW photographers have most probably also started. In any case, the accuracy requirements during the assembling and aligning stage of thousands of individual shots requires professional level equipment (as Nick wrote to me). And he had to travel all around Earth for completing the job ;-)

Anyway, your venture sounds like a most gratifying and creative holiday project!

Cheers,
Fridger

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PostPosted: Sun, 20-08-17, 21:47 GMT 
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Gravitational Lensing (GL)

Currently, GL serves as a main tool in the all-important searches of Dark Matter, EXO planets etc. There is practically NO guesswork involved: The underlying framework is Einstein's highly respected General Relativity according to which light rays are deflected by gravity (i.e. Mass).

The nice feature is that in the limit of weak gravity the GL formalism collapses into one that is isomorphic to Optics, with caustics and all that. Hence in practice good knowledge of Optics is sufficient for working out GL phenomena quantitatively. One of my favorite reviews (for physicists though) is by Prof. Ramesh Narayan, Harvard Univ

In celestia.Sci, Dawoon (aka dirkpitt) and I implemented a complete framework of so-called strong, weak and micro lensing. Here is a typical rendering of a deep space configuration for strong GL:

Consider the very massive cluster of elliptical galaxies, notably NGC 6166 in the image center. The first image has Gravitational Lensing effects switched off. Then it looks like so:
[by all means click on image and then hit your browser's fullscreen key (F11 for FF)]
Attachment:
n6166_noLensing.jpg
n6166_noLensing.jpg [ 84.22 KiB | Viewed 22 times ]


Now, let's switch on GL.

Explanation:
========
In this display, the very massive E2 galaxy NGC 6166 is 273 Mpc (!!) away from the observer, while far behind NGC 6166 at ~420 Mpc distance is our "tiny" SBc- type Milkyway, which cannot be observed directly anymore. Milkyway, NGC 6166 and observer are approximately (but not exactly) positioned on a straight line, whence --according to GL--we expect a magnification of the tiny Milkyway into a distorted double image of the SBc-type MilkyWay, looking as follows:
[by all means click on image and then hit your browser's fullscreen key (F11 for FF)]
Attachment:
n6166_Lensing.jpg
n6166_Lensing.jpg [ 78.44 KiB | Viewed 22 times ]


Bringing the MW, ngc 6166 and the observer more precisely into a straight-line configuration results in a conspicuous so-called "Einstein circle", with the super-massive NGC 6166 located in the center. ...Indeed!

See here:
[by all means click on image and then hit your browser's fullscreen key (F11 for FF)]
Attachment:
n6166_Lensing_Einstein.jpg
n6166_Lensing_Einstein.jpg [ 118.84 KiB | Viewed 22 times ]


++++++++++++
By carefully measuring the size of the Einstein ring, we can learn something important about the system. what could that be???
++++++++++++

Enjoy,

Cheers,
Fridger

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PostPosted: Mon, 21-08-17, 0:16 GMT 
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Wow, this is beautiful. Thanks for coding it.

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PostPosted: Mon, 21-08-17, 13:16 GMT 
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t00fri wrote:
++++++++++++
By carefully measuring the size of the Einstein ring, we can learn something important about the system. what could that be???
++++++++++++

If the distances to the "lens" and the object behind it are known, we could calculate the mass of the lens object?
Or maybe it's the other way around and we want to calculate distances?


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