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  1. #41
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    blaise and Fuzz and Al and Carol and Declan and All--

    I know this thread is a month old, but I did NOT know this forum even existed until tonight!

    I am learning a lot about flats, for sure. (There was a BIG "discussion" over on the Yahoo ImagesPlus forum about flats. HUGE.)

    Here is my humble submission of blaise's image (which I like very much, blaise).

    I hope it is not too late for you to critique it.

    ImagesPlus-->Nikon NX2-->ImagesPlus-->Nikon NX2-->LView Pro-->final jpg

    --Bill
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    killer's Astrophotography</a>

  2. #42
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    This has been an extremely helpful post. I wish I had seen the thread earlier. Thanks, all !! You guys are doing amazing work, my processing chops are not good at all. Sometimes it seems that everything I try just makes things look worse instead of better, so I'm concentrating on the mechanics of actually collecting the data right now. I understand how to do the dark and flat calibrations with the DSI, but using the DSLR in this way is a new thing for me. I'm an old-time film shutterbug, but it seems that DSLR astrophotography requires one to learn new ways of thinking about photography.
    Again, thanks for this valuable information.
    --Al
    Last edited by alsetalokin; 07-06-2010 at 11:19 AM.

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    ETX125AT guiding WO Megrez 90 Apo/CGEM mount w/ polar scope
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  3. #43
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    I wish I had seen the thread earlier.
    There are many very useful threads that get buried in a format such as this.
    Thank you for dredging this up, Seal Killer. It will be easier to find from now on.

    Nice work, btw.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
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    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

  4. #44
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    Doesn't work at all in PS CS5.

  5. #45
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    Oops, what happened? OK, try again:



    Quote Originally Posted by EricFD View Post
    P.S.

    I don't think this will work. This is for the RAW imaging format, which I already have on all of my graphic manipulation software.

    FITS are used by professional astronomers who use an entirely different platform that is far more sophisticated than either a Windows or MacOS platform. FITS are the most comprehensive and sophisticated imaging format in existence and contain far more data than any other imaging format. And in its pristine form, it is not compatible with any graphic software designed for a Windows or MacOS platform. That's why you need the FITS liberator to make it compatible with Photoshop. But only with versions of Photoshop 6.0 (I think it's version 6.0) or higher can you donwload the FITS liberator.

    But, I appreciate the thought.
    Doesn't work at all in PS CS5 either.

    Quote Originally Posted by blaise View Post
    I should never have posted this. I never thought it would cause such a hassle : )

    Certianly there must be some way for us to reliably share, in a format that is accessible to all of us, raw data to practise processing skills on. Uploading a converted jpg or bmp, etc to a file uploading service doesn't reliably contain all the data of the original image. So, it has to be in FITS or RAW (CR2 or similiar) original data.

    I believe my 450D saves in CR2 which once aligned and stacked, is saved as FITS ( I am pretty certain both DSS and Nebulosity save it as such).
    Use whatever you like (that's common!) and just zip it. As far as a demosaiced raster container goes the most robust is OpenEXR. If you need a host I'll put it up on my server. I read on wiki about FITS just now, and I remember throwing away a stack of FITS SI Installation CDs back on the Sun system. I think I remember seeing FITS as a main feature suite of apps on HP Unix systems tailored for SIR from ancient times too. As a 3D artist interested in simulations at the time I thought it would be interesting to study but it's geared for the scientific crowed and the file format is not supported by ANYTHING commercial - as we're seeing here. I think it's readily supported on all unix systems tho. I think Gimp as installed on any *nix system (including Mac OS X), will just load it directly. The only problem with that is that The Gimp is expressly 8-bit and 8-bit only. It seemed to me back when I began to look into it, to basically be a programmer's all-purpose archival container - like maybe the project file data from 20 different custom applications where they can just stuff everything into one file, vector, raster, text, DB, loggings, the works. The format is nice and simple like programmers like it.
    Last edited by Tesselator; 07-11-2010 at 03:59 PM.

  6. #46
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    It certainly seems to me that Gimp handles more than "8-bit and 8-bit only". When I open the Canon RAW .cr2 file with Gimp and UFRaw, it comes up and gives me the option to save as a .fit (as well as many other formats) and when I tell it to save as a .bmp it gives me some options re bit depth.
    Certainly my Gimp installation fully supports the .fit format, as far as I can tell. At least it opens them, in multiple layers, with more information than I can handle, for sure.

    I don't know if this is what you are referring to...?

    Last edited by alsetalokin; 07-11-2010 at 05:23 PM.

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    ETX125AT guiding WO Megrez 90 Apo/CGEM mount w/ polar scope
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  8. #47
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    Quote Originally Posted by alsetalokin View Post
    It certainly seems to me that Gimp handles more than "8-bit and 8-bit only". When I open the Canon RAW .cr2 file with Gimp and UFRaw, it comes up and gives me the option to save as a .fit (as well as many other formats) and when I tell it to save as a .bmp it gives me some options re bit depth.
    No sir. Not as far as I know. No 16 bit in Gimp! Here's the blurb from the current faq:

    "When can we see 16-bit per channel support (or better)?

    For some industries, especially photography, 24-bit colour depths (8 bits per channel) are a real barrier to entry. Once again, it's GEGL to the rescue. Work on integrating GEGL into GIMP will begin after 2.4 is released. Once that work is completed, GIMP will support 16 bits per channel. If you need such support now and can't wait, cinepaint and krita support 16 bits per channel now.

    It should be noted that for publishing to the web, the current GIMP release is good enough."

    Good enough... LOL. Not even! If you have a saver option that allows 16bit output then it's probably padding 8-bit data. Likewise there is no 12 or 14 bit Camera RAW support either. There are readers that will open the files but the data is immediately converted to 8-bit. This RAW issue was absolutely the case a year ago. If it's changed since then then the documentation and FAQ don't reflect it and it's a new feature that I'm unaware of. There may also be 3rd party plugins capable of circumventing the Gimp 8-bit limitation but if there are I don't know about them; how they work, their own limitations, and etc.

    Certainly my Gimp installation fully supports the .fit format, as far as I can tell. At least it opens them, in multiple layers, with more information than I can handle, for sure.

    I don't know if this is what you are referring to...?

    It might be. My reader looks like this:


    But Gimp doesn't "fully" support FITS. It can only read the most common raster chunks. Gimp is the GNU Image Manipulation Package primarily a raster editor for the *nix platforms, so it's limited to just that in most cases. There are like, a few hundred different documented kinds of data that the FITS container format supports. I think Gimp supports only one of those. And only in 8-bit AFAIK.
    Last edited by Tesselator; 07-11-2010 at 10:52 PM.

  9. #48
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    Also, if you'll notice the BMP format saver you are showing is specifying 32 bit rasters, not 32 or 16 bit per channel. That's 8-bits of R, G, B, and X is probably the Alpha channel. So it's 8+8+8=24+8=32. A 16-bit per channel file refered to in the same way is 16+16+16+48+16=64 or 16+16+16+48+8=56. 32 bit files (HDRI) are the same deal again.

  10. #49
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    20 min. edit limit.


    Also, if you'll notice the BMP format saver you are showing is specifying 24 bit rasters + 8 bits of alpha, not 32 or 16 bit per channel. That's 8-bits of R, G, B, and X is probably the Alpha channel. So it's 8+8+8=24+8=32. A 16-bit per channel file refered to in the same way is 16+16+16=48+16=64 or 16+16+16=48+8=56. 32 bit files (HDRI) are the same deal again. 32+32+32=96bit.

    For clarity sake 8bit and 16bit files (except for 16-bit half HDRs) are referring to bits of accuracy within the non-extended ranges. They're integer based formats representing divisional accuracies of the color component values from 0 ("black") to 1 ("white"). 32 bit formats like OpenEXR and etc. are (can be) floating point descriptions of extended range data sets where values brighter than 100% and darker than 0% black are (can be) represented. I keep saying "can be" because the OpenEXR I'm sighting is inclusive and OpenEXR images for example, can have an arbitrary number of channels, each with a different data type.

    You can think of it in this way:

    A typical 8-bit file is a flight of stairs from the 1st floor to the 2nd floor with 16777216 steps.
    12 or 16 (36-bit or 48-bit color) files also only go from the 1st floor to the 2nd floor but just have a lot more steps.
    32 bit HDR files also have a bunch more steps but the stair case additionally goes from B5 to the fifth floor.

    [where the floors are representing luminance values of course.]
    --
    All this talk of stairs is making me tired. Where's the elevator?
    Last edited by Tesselator; 07-11-2010 at 11:38 PM.

 

 
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