Quote:Are you sure? I am looking at my bias frames, and they are all dark, and I look at the master offset in DSS and it is dark as dark can be.As I recall, I took them at 1/2000 shutter speed with the lens cap on in my office, captured using BackyardEOS. I am not sure if somehow somewhere they got mixed up, but they look fine in the directory on my drive.
Celestron C-8 SCT
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Quote:First don't save your file from DSS instead make a copy of the autosave.tif and then use imagemagick to convert it to 16 bit. My understanding is that DSS has a bug in the 16bit save routine.
Quote:Here is a link to a screen shot of my master offset in DSS:https://drive.google.com/#folders/0By0hG91nGRL9ckxUeXAxUXdTLTQ
Quote:Quote:First don't save your file from DSS instead make a copy of the autosave.tif and then use imagemagick to convert it to 16 bit. My understanding is that DSS has a bug in the 16bit save routine.Reference is below. I have seen a huge improvement using the method suggested to bypass the bug.http://www.astronomyforum.net/astrophotography-image-processing-forum/154722-...
SCOPE: Celestron 9.25 CGEM GUIDESCOPE: Orion Awesome Autoguider CAMERA: Unmodded Canon T3i BANK ACCOUNT: Empty
Quote:Reference is below. I have seen a huge improvement using the method suggested to bypass the bug.
1987 Meade LX3 2120 10" SCT on hypertuned EQ6 Pro Baader Self-Mod Canon XS_CLS Clip Filter DSI color_Orion ST80 Coulter 10" Compact Odessey Dob http://www.astrobin.com/users/shawnhar
Can someone do an autopsy on this image to figure out what I am doing wrong?
Quote: The Autosave.tif file is itself problematic. It contains 16-bits of real data + 16-bits of zeroes within a 32-bit tif wrapper (quite why it does this is unclear).
Quote:Some editing/AP packages will not open the Autosave.tif file at all.
Quote:Because of a bug in DSS, the "File - Save As" command does not create a high-quality file. It creates a 16-bit tif wrapper with 8-bit data inside it.
Paul B. Jones http://www.astrobin.com/users/bunyon/
Quote:Quote: The Autosave.tif file is itself problematic. It contains 16-bits of real data + 16-bits of zeroes within a 32-bit tif wrapper (quite why it does this is unclear). Quote:Some editing/AP packages will not open the Autosave.tif file at all.Why this is so is easy - its a private TIFF format that DSS uses to cache intermediate data during stacking and for reloading once the stacking is done - its not designed for users to play with. Hence many programs can't deal with it.Quote:Because of a bug in DSS, the "File - Save As" command does not create a high-quality file. It creates a 16-bit tif wrapper with 8-bit data inside it.I find this troubling as this is not my experience at all. At least the evidence when opening a 16 bit in Images plus is contrary to this - e.g. the histogram data statistics do not concur and there are no gaps (combing) which is what you would expect with an 8 bit depth file maskerading as a 16 bit file. If this is really the case then posterization of brightness data after even a basic stretch would be very evident (like it is in GIMP which is still stuck at 8 bits). I don't see this after any sort of stretching in Images Plus ... so it is now greatly puzzling me why we are just hearing of this.Which makes me think that if there is a bug it may be down to specific types of RAW file input (i.e. from a particular camera model) The only thing I can think might be an issue is if some has been using a newer model camera and hasn't picked up the DSS beta with the newest DCRaw program - i.e. the problem actually lies with using an too old version of the DCraw program that DSS uses.It would be interesting if more information was available - camera used etc I've just done an intensive Google on this issue and I can find nothing else reported or said by anyone. The nearest is Sander Pool (DSS Yahoo Groups guru) mentioning that post processing in GIMP is limited by it 8 bit depth. I would have though if anyone was going to make a song+dance of this bug Sander would!
Quote: Eventually this bug should get fixed. Until it does, for the best possible data out of DSS you need to use the Autosave.tif file that it creates automatically after stacking is completed.
Quote: I think this is mis-informed info, someone is confused about 8bit vs 16bit.
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Quote:@Shawn - since you're familiar with DSS, would you mind giving ICallHimGamblor directions on how to save an unstretched Master offset tiff file?
Quote:I have uploaded a random sub from a week earlier on a completely different target, Hickson 93.https://docs.google.com/file/d/0By0hG91nGRL9clVEX25QUFFCakk/edit?usp=sharingDoes it have the same issues? If so, we can eliminate clouds and dew and stuff, right?