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Need help with FITS -
Is anyone here familair with fits image reading, conversion, etc?
tia Jerry |
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Need help with FITS -
On Sat, 06 Jan 2007 03:10:27 -0600, jerry wrote:
Is anyone here familair with fits image reading, conversion, etc? tia Jerry What is it you want to do? There are dozens of programs that can be used to read, write, and display FITS files. If you're looking to spin something yourself, the easiest way is to use the freely available CFITSIO library, at http://heasarc.nasa.gov/fitsio/fitsio.html . This is written by the same people who maintain the FITS standard. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#3
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Need help with FITS -
Chris L Peterson wrote: On Sat, 06 Jan 2007 03:10:27 -0600, jerry wrote: Is anyone here familair with fits image reading, conversion, etc? tia Jerry What is it you want to do? There are dozens of programs that can be used to read, write, and display FITS files. If you're looking to spin something yourself, the easiest way is to use the freely available CFITSIO library, at http://heasarc.nasa.gov/fitsio/fitsio.html . This is written by the same people who maintain the FITS standard. Thanks for replying Chris. I have no working knowledge of fits files. Im trying to get v-spec running. V-spec requires fits image files. I need to convert jpegs and bmp files into FITS - somehow. I downloaded a converter from NASA but it asks for two file pathways? I dont even know where to begin. Everyone here avoids these issues by using canned software like aip4.win ? which evidently can convert files formats at will. One guy puts his jpegs or bmps into aip4 and out comes fits files which he can then read with a fits reader or processes with v-spec. I dont understand what two pathways for a single fits file means? Im missing something basic ... The whole issue is to be able to take whatever file format different cameras out put and be able to convert them into fits files I can then use with V-spec or any other software requiring fits image files. There are 8 bit, 16 bit, 32 bit type files ..... Im lost! Thats the problem. Jerry .. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#4
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Need help with FITS -
On Sun, 07 Jan 2007 00:35:43 -0600, jerry warner
wrote: Thanks for replying Chris. I have no working knowledge of fits files. Im trying to get v-spec running. V-spec requires fits image files. I need to convert jpegs and bmp files into FITS - somehow. I downloaded a converter from NASA but it asks for two file pathways? I dont even know where to begin. I don't know what converter you are using. I'd guess that the two paths it's asking for are the source file and the destination file. So if you have a source IMG.BMP, the converter probably expects something like CONVERT IMG.BMP IMG.FITS. Everyone here avoids these issues by using canned software like aip4.win ? which evidently can convert files formats at will. Quite a few astronomical imaging apps can convert between formats. Converting from JPEG to FITS is not common, since JPEG files are fairly useless for any sort of analysis, and that's usually why you want FITS. If you intend to do analysis, you should try to avoid JPEG files. BMPs are better, but they are only 8-bit (or 8-bit per color channel), which is often very limiting. Something with more bits is better. Are you using a digicam of some sort? If it has RAW, that is often 10-12 bits. FITS is generally the native file format for astronomical cameras, or for astronomical software that interfaces with cameras. If you have Photoshop, you could download a free plugin that lets you save in FITS format, so you could use that for conversion. Another option is IRIS, http://www.astrosurf.com/buil/us/iris/iris.htm . This is a powerful image processing program, although it's hard to use (careful, it has a retarded installer that will try to place the program in your root directory). But it can read JPEGs and BMPs and write FITS. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#5
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Need help with FITS -
jerry warner wrote:
Chris L Peterson wrote: On Sat, 06 Jan 2007 03:10:27 -0600, jerry wrote: Is anyone here familair with fits image reading, conversion, etc? tia Jerry What is it you want to do? There are dozens of programs that can be used to read, write, and display FITS files. If you're looking to spin something yourself, the easiest way is to use the freely available CFITSIO library, at http://heasarc.nasa.gov/fitsio/fitsio.html . This is written by the same people who maintain the FITS standard. Thanks for replying Chris. I have no working knowledge of fits files. Im trying to get v-spec running. V-spec requires fits image files. I need to convert jpegs and bmp files into FITS - somehow. I downloaded a converter from NASA but it asks for two file pathways? I dont even know where to begin. Hi, There are lots of image converters around. I think vspec wants unsigned 16 bit Fits, something you can create using my ImageTOOLSca http://arnholm.org/astro/software/ImageTOOLSca/ . It will take jpeg and bmp as input and write FITS, but I would not recommend such conversions from 8bit to 16bit for serious work, better to work with original Fits. Clear skies Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457 |
#6
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Need help with FITS -
Chris L Peterson wrote: On Sun, 07 Jan 2007 00:35:43 -0600, jerry warner wrote: Thanks for replying Chris. I have no working knowledge of fits files. Im trying to get v-spec running. V-spec requires fits image files. I need to convert jpegs and bmp files into FITS - somehow. I downloaded a converter from NASA but it asks for two file pathways? I dont even know where to begin. I don't know what converter you are using. I'd guess that the two paths it's asking for are the source file and the destination file. So if you have a source IMG.BMP, the converter probably expects something like CONVERT IMG.BMP IMG.FITS. Oh well if thats all it means, that has to be it. No instructions came with the software I pulled off a nasa site and no labeling of windows on the software face except Path-1, Path-2. Everyone here avoids these issues by using canned software like aip4.win ? which evidently can convert files formats at will. Quite a few astronomical imaging apps can convert between formats. Converting from JPEG to FITS is not common, since JPEG files are fairly useless for any sort of analysis, and that's usually why you want FITS. If you intend to do analysis, you should try to avoid JPEG files. BMPs are better, but they are only 8-bit (or 8-bit per color channel), which is often very limiting. Something with more bits is better. Are you using a digicam of some sort? If it has RAW, that is often 10-12 bits. Im using a Tucam, and Sac-IV, and may be using several older digital cameras like the Kodak DC-4 etc... What I have however are many jpeg files sent to me by others I want to process to send back. I should get these people to send in some other format. FITS is generally the native file format for astronomical cameras, or for astronomical software that interfaces with cameras. If you have Photoshop, you could download a free plugin that lets you save in FITS format, so you could use that for conversion. I have Photoshop and can do this. I wasnt aware there was a fits plugin. Another option is IRIS, http://www.astrosurf.com/buil/us/iris/iris.htm . This is a powerful image processing program, although it's hard to use (careful, it has a retarded installer that will try to place the program in your root directory). But it can read JPEGs and BMPs and write FITS. I have IRIS but have never activated it because it seemed so complicated. I think the plugin for Photoshop may solve this. But now that I understand "two pathways" I may have the NASA converter up quick - I am sure you have to be right about this. What confused me about the NASA software with "two pathways" was their brief instructions mentioned two or more "file extensions". I open the software and saw two windows for two pathways ... and blocked mentally. Thank you Chris. I think Im there now. Jerry _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#7
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Need help with FITS -
"Carsten A. Arnholm" wrote: Hi, There are lots of image converters around. I think vspec wants unsigned 16 bit Fits, OK, this helps to know. This nails down what version of FITS I need for v-spec. I was very unsure about that. something you can create using my ImageTOOLSca http://arnholm.org/astro/software/ImageTOOLSca/ . It will take jpeg and bmp as input and write FITS, but I would not recommend such conversions from 8bit to 16bit for serious work, better to work with original Fits. Believe me I understand this. This is not "serious" work. Not yet at least. This is simply to get jpeg and bmp files from Tucam and and other simple cameras into the proper fits format (unsigned 16 bit fits!) so I can do some low level processing and generate a graph. ___ I am not sure what "unsigned" 16 bit fits means? Is there a "signed" 16 bit fits? I also have people send me jpegs they want me to make a spectrum for them from. If I could use v-spec I could add a graph. For serious work I fully understand the st7 etc and wares like ccdsoft have the option of saving in fits, direct to v-spec. But I dont personally do not own one of those cameras and am new to v-spec and have never worked with FITS at all. (Maybe some day I will win the lotto and can afford an st9 or a Canon...) Thanks very much for this help - Jerry Clear skies Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457 |
#8
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Need help with FITS -
Big Mak Attack wrote:
"Carsten A. Arnholm" wrote: Hi, There are lots of image converters around. I think vspec wants unsigned 16 bit Fits, OK, this helps to know. This nails down what version of FITS I need for v-spec. I was very unsure about that. something you can create using my ImageTOOLSca http://arnholm.org/astro/software/ImageTOOLSca/ . It will take jpeg and bmp as input and write FITS, but I would not recommend such conversions from 8bit to 16bit for serious work, better to work with original Fits. Believe me I understand this. This is not "serious" work. Not yet at least. This is simply to get jpeg and bmp files from Tucam and and other simple cameras into the proper fits format (unsigned 16 bit fits!) so I can do some low level processing and generate a graph. Hi, If webcam capture is your starting point, then they typically deliver AVI video files originally. My program can also convert directly from AVI to 16 bit unsigned FITS, optionally also performing gamma adjustment at the same time (ref also. http://preview.tinyurl.com/y27kb7) ___ I am not sure what "unsigned" 16 bit fits means? Is there a "signed" 16 bit fits? Yes. It refers to how integer numbers are interpreted on the computer. Integers can be with or without sign, the unsigned ones are all positive (zero inclusive) while the signed ones can be both negative and positive. Fits files can contain both types of integers (unfortunately). The ranges these variants represent are slightly different. The way FITS files are used my many programs is a bit messy, so often you have to deal with the signed/unsigned issue, i.e. you may have to know the requirement of each program to get it right. I also have people send me jpegs they want me to make a spectrum for them from. If I could use v-spec I could add a graph. It is possible to convert to FITS, but not optimal as mentioned. Be aware that normally, JPG files are in colour but FITS files are mostly monochrome (grayscale). My program can generate both monochrome and colour FITS from other formats, but vspec will expect monochrome only. For serious work I fully understand the st7 etc and wares like ccdsoft have the option of saving in fits, direct to v-spec. But I dont personally do not own one of those cameras and am new to v-spec and have never worked with FITS at all. (Maybe some day I will win the lotto and can afford an st9 or a Canon...) Thanks very much for this help - You are welcome! Clear skies Carsten A. Arnholm http://arnholm.org/ N59.776 E10.457 |
#9
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Need help with FITS -
On Mon, 08 Jan 2007 00:50:14 -0600, Big Mak Attack
wrote: Im using a Tucam, and Sac-IV, and may be using several older digital cameras like the Kodak DC-4 etc... What I have however are many jpeg files sent to me by others I want to process to send back. I should get these people to send in some other format. To the extent you have control over it, make sure that you have streaming compression disabled, and if possible use a capture program like K3CCD that can save directly to lossless formats. K3CCD can even save to FITS directly. I have Photoshop and can do this. I wasnt aware there was a fits plugin. Try this: http://www.astroshed.com/fitsplug/fitsplug.htm . The old shareware version is all you need. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#10
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Need help with FITS -
Carsten A. Arnholm wrote:
___ I am not sure what "unsigned" 16 bit fits means? Is there a "signed" 16 bit fits? Yes. It refers to how integer numbers are interpreted on the computer. Integers can be with or without sign, the unsigned ones are all positive (zero inclusive) while the signed ones can be both negative and positive. Fits files can contain both types of integers (unfortunately). The ranges these variants represent are slightly different. The way FITS files are used my many programs is a bit messy, so often you have to deal with the signed/unsigned issue, i.e. you may have to know the requirement of each program to get it right. 16-bit integers are signed in FITS, i.e. the values stored in the image array go from -32768 to 32767. The equivalent of unsigned, i.e. from 0 to 65535, can be achieved using the scaling header keywords called BSCALE and BZERO set to 1 and 32768 respectively. Unsigned value = BSCALE * (FITS value) + BZERO. I don't know if it is still the case, but there was a time when some CCD-camera manufacturers for the amateur market thought that FITS was unsigned, leading to confusion if images were exported to kosher FITS readers. Malcolm Currie |
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