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FITS Tools

FITS metainformation

CamiFITS.fits_info — Method
fits_info(f::FITS [, hduindex=1] [; nr=false [, hdr=true]])
fits_info(hdu::FITS_HDU; nr=false, hdr=true)

Metafinformation and data of a given FITS_HDU object with optional record numbering.

  • hduindex: HDU index (::Int - default: 1 = primary hdu)
  • nr: include cardindex (::Bool - default: false)
  • hdr: show header (::Bool)

Example:

To demonstrate fits_info we first create the fits object f for subsequent inspection.

julia> filnam = "minimal.fits";

julia> f = fits_create(filnam; protect=false);

julia> fits_info(f)

File: minimal.fits
hdu: 1
hdutype: 'PRIMARY '
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
EXTEND  =                    T / FITS dataset may contain extensions
END

Any[]

julia> rm(filnam); f = nothing
fits_info(filnam::String [, hduindex=1] [; nr=true [, hdr=true]])

Same as above but creating the fits object by reading filnam from disc and with default record numbering.

  • hduindex: HDU index (::Int - default: 1 = primary hdu)
  • nr: include cardindex (::Bool - default: true)
  • hdr: show header (::Bool)

Example:

julia> filnam = "minimal.fits";

julia> fits_create(filnam; protect=false);

julia> fits_info(filnam)

File: minimal.fits
hdu: 1
hdutype: 'PRIMARY '
DataType: Any
Datasize: (0,)

  nr | Metainformation:
---------------------------------------------------------------------------------------
   1 | SIMPLE  =                    T / file does conform to FITS standard
   2 | BITPIX  =                   64 / number of bits per data pixel
   3 | NAXIS   =                    1 / number of data axes
   4 | NAXIS1  =                    0 / length of data axis 1
   5 | EXTEND  =                    T / FITS dataset may contain extensions
   6 | END

Any[]

julia> rm(filnam)
source
CamiFITS.fits_record_dump — Function
fits_record_dump(filnam [, hduindex=0] [; hdr=true [, dat=true [, nr=true [, msg=true]]]])

Listing of all single-line records (card records) as read from filnam on disc. The dump proceeds without casting of FITS objects; i.e., without FITS-conformance testing.

  • hduindex: HDU index (::Int - default: 1 = primary hdu)
  • hdr: show header (::Bool - default: true)
  • dat: show data (::Bool - default: true)
  • nr: include record numbers (::Bool - default: true)
  • msg: print message (::Bool)

Example:

julia> filnam = "test.fits";

julia> data = [typemin(UInt32),typemax(UInt32)];

julia> fits_create(filnam, data; protect=false);

julia> dump = fits_record_dump(filnam; msg=false);

julia> for i=3:8 println(dump[i]) end
   3 | NAXIS   =                    1 / number of data axes
   4 | NAXIS1  =                    2 / length of data axis 1
   5 | BSCALE  =                  1.0 / default scaling factor
   6 | BZERO   =           2147483648 / offset data range to that of unsigned integer
   7 | EXTEND  =                    T / FITS dataset may contain extensions
   8 | END

julia> dump[37]
"  37 | UInt8[0x80, 0x00, 0x00, 0x00, 0x7f, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, ⋯, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]"]"

julia> rm(filnam); f = data = dump = nothing
source

FITS creation, extension and collection

CamiFITS.fits_create — Function
fits_create(filnam [, data [; protect=true]])

Create .fits file of given filnam and return Array of HDUs. Key:

  • data: data primary hdu (::DataType)
  • protect: overwrite protection (::Bool)

Examples:

julia> filnam = "test.fits";

julia> f = fits_create(filnam, data; protect=false);

julia> fits_info(f)

File: test.fits
hdu: 1
hdutype: 'PRIMARY '
DataType: Int64
Datasize: (3, 3)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    2 / number of data axes
NAXIS1  =                    3 / length of data axis 1
NAXIS2  =                    3 / length of data axis 2
EXTEND  =                    T / FITS dataset may contain extensions
END

3×3 Matrix{Int64}:
 11  21  31
 12  22  23
 13  23  33

julia> rm("minimal.fits"); f = nothing
source
CamiFITS.fits_extend! — Method
fits_extend!(f::FITS, data_extend; hdutype="IMAGE")
fits_extend!(filnam::String, data_extend; hdutype="IMAGE")

HDU array in which the FITS object f or FITS file filnam is extended with the data of data_extend in the format of the specified hdutype.

Examples:

julia> filnam = "example.fits";

julia> fits_create(filnam; protect=false);

julia> table = let
        [true, 0x6c, 1081, 0x0439, 1.23, 1.01f-6, 1.01e-6, 'a', "a", "abc"],
        [false, 0x6d, 1011, 0x03f3, 23.2, 3.01f-6, 3.01e-6, 'b', "b", "abcdef"]
        end;

julia> fits_extend!(filnam, table; hdutype="table");

julia> fits_info(filnam, 2; hdr=false)
2-element Vector{String}:
 " 1 108 1081 1081  1.23 1.01E-6 1.01D-6 a a    abc"
 " 0 109 1011 1011 23.20 3.01E-6 3.01D-6 b b abcdef"

julia> rm(filnam)
source
CamiFITS.fits_collect — Method
fits_collect(fileStart::String, fileStop::String [; protect=true[], msg=true]])

Combine "fileStart" with "fileStop" (with mandatory ".fits" extension)

Key:

  • protect::Bool: overwrite protection
  • msg::Bool: allow status message

Example:

julia> for i=1:5
           data = [0 0 0; 0 i 0; 0 0 0]
           fits_create("T$i.fits", data; protect=false)
       end

julia> f = fits_collect("T1.fits", "T5.fits"; protect=false);
'T1-T5.fits': file created

julia> fits_info(f)[:,:,2]

File: T1-T5.fits
hdu: 1
hdutype: 'PRIMARY '
DataType: Int64
Datasize: (3, 3, 5)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    3 / number of data axes
NAXIS1  =                    3 / length of data axis 1
NAXIS2  =                    3 / length of data axis 2
NAXIS3  =                    5 / length of data axis 3
EXTEND  =                    T / FITS dataset may contain extensions
END

3×3 Matrix{Int64}:
 0  0  0
 0  2  0
 0  0  0

julia> for i = 1:5 rm("T$i.fits") end

julia> rm("T1-T5.fits"); f = nothing
source

FITS reading, copying and saving

CamiFITS.fits_read — Method
fits_read(filnam::String)

Read .fits file and return Array of FITS_HDUs

Example:

julia> filnam = "minimal.fits";

julia> fits_create(filnam; protect=false);

julia> f = fits_read(filnam);

julia> fits_info(f)
hdu: 1
hdutype: PRIMARY
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
BZERO   =                  0.0 / offset data range to that of unsigned integer
BSCALE  =                  1.0 / default scaling factor
EXTEND  =                    T / FITS dataset may contain extensions
END

Any[]

julia> rm(filnam); f = nothing
source
CamiFITS.fits_save_as — Method
fits_save_as(f::FITS, filnam::String [; protect=true])

Save the FITS object under the name filnam. Key:

  • protect::Bool: overwrite protection
julia> f = fits_create("minimal.fits"; protect=false);

julia> fits_save_as(f, "kanweg.fits"; protect=false);

julia> f = fits_read("kanweg.fits");

julia> fits_info(f)
File: kanweg.fits
hdu: 1
hdutype: PRIMARY
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
BZERO   =                  0.0 / offset data range to that of unsigned integer
BSCALE  =                  1.0 / default scaling factor
EXTEND  =                    T / FITS dataset may contain extensions
COMMENT    Extended FITS HDU   / http://fits.gsfc.nasa.gov/
END

Any[]
source
CamiFITS.fits_copy — Function
fits_copy(filnam1 [, filnam2=""] [; protect=true]])

Copy filnam1 to filnam2 (with mandatory .fits extension) Key:

  • protect::Bool: overwrite protection
  • msg::Bool: allow status message

Examples:

julia> fits_create("test1.fits"; protect=false);

julia> fits_copy("test1.fits", "test2.fits"; protect=false);
'test1.fits' was copied under the name 'test2.fits'

julia> rm.(["test1.fits", "test2.fits"]);
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FITS keyword tools

CamiFITS.fits_add_key! — Method
fits_add_key!(f::FITS, hduindex::Int, key::String, val::Any, com::String)

Add a header record of given 'key, value and comment' to 'HDU[hduindex]' of file with name 'filnam'

Example:

julia> filnam = "minimal.fits";

julia> f = fits_create(filnam; protect=false);

julia> fits_add_key!(f, 1, "KEYNEW1", true, "This is the new key");

julia> fits_info(f)

File: minimal.fits
hdu: 1
hdutype: 'PRIMARY '
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
EXTEND  =                    T / FITS dataset may contain extensions
KEYNEW1 =                    T / This is the new key
END

Any[]
source
CamiFITS.fits_delete_key! — Method
fits_delete_key!(f::FITS, hduindex::Int, key::String)

Delete a header record of given key, value and comment from the FITS_HDU f of given hduindex.

Examples:

julia> filnam = "minimal.fits";

julia> f = fits_create(filnam; protect=false);

julia> fits_add_key!(f, 1, "KEYNEW1", true, "This is the new key");

julia> cardindex = get(f.hdu[1].header.map,"KEYNEW1", nothing)
8

julia> keyword = f.hdu[1].header.card[cardindex].keyword
"KEYNEW1"

julia> cardindex = get(f.hdu[1].header.map,"KEYNEW1", nothing)
8

julia> fits_delete_key!(f, 1, "KEYNEW1");

julia> cardindex = get(f.hdu[1].header.map,"KEYNEW1", nothing)

julia> fits_delete_key!(f, 1, "NAXIS");
ERROR: FITSError: 17 - illegal keyword deletion (mandatory keyword)
Stacktrace:
 [1] fits_delete_key!(f::FITS, hduindex::Int64, key::String)
   @ CamiFITS c:\Users\walra\.julia\dev\CamiFITS.jl\src\fits_public_sector.jl:495
 [2] top-level scope
   @ REPL[24]:1
source
CamiFITS.fits_edit_key! — Method
fits_edit_key!(f::FITS, hduindex::Int, key::String, val::Any, com::String)

Edit a header record of given 'key, value and comment' to 'HDU[hduindex]' of file with name 'filnam'

Example:

julia> using Dates

julia> data = DateTime("2020-01-01T00:00:00.000");

julia> strExample="minimal.fits";

julia> f = fits_create(strExample; protect=false);

julia> fits_add_key!(f, 1, "KEYNEW1", true, "this is record 5");

julia> fits_edit_key!(f, 1, "KEYNEW1", data, "record 5 changed to a DateTime type");

julia> fits_info(f.hdu[1])
hdu: 1
hdutype: 'PRIMARY '
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
EXTEND  =                    T / FITS dataset may contain extensions
KEYNEW1 = '2020-01-01T00:00:0' / record 5 changed to a DateTime type
END

Any[]
source
CamiFITS.fits_rename_key! — Method
fits_rename_key!(filnam::String, hduindex::Int, keyold::String, keynew::String)

Rename the key of a header record of file with name 'filnam'

Example:

julia> filnam="minimal.fits";

julia> f = fits_create(filnam; protect=false);

julia> fits_add_key!(f, 1, "KEYNEW1", true, "this is a new record");

julia> fits_rename_key!(f, 1, "KEYNEW1",  "KEYNEW2");

julia> fits_info(f.hdu[1])
hdu: 1
hdutype: 'PRIMARY '
DataType: Any
Datasize: (0,)

Metainformation:
SIMPLE  =                    T / file does conform to FITS standard
BITPIX  =                   64 / number of bits per data pixel
NAXIS   =                    1 / number of data axes
NAXIS1  =                    0 / length of data axis 1
BZERO   =                  0.0 / offset data range to that of unsigned integer
BSCALE  =                  1.0 / default scaling factor
EXTEND  =                    T / FITS dataset may contain extensions
COMMENT    Extended FITS HDU   / http://fits.gsfc.nasa.gov/
KEYNEW2 =                    T / this is a new record
END

Any[]
source

FITS keyword description tool

In the CamiFITS package the mandatory FITS keywords are autogenerated. To support easy user access to the definition of all reserved FITS keywords (mandatory or non-mandatory) CamiFITS includes the fits_keyword tool.

The description of the FITS keywords is provided by fits_keyword:

julia> fits_keyword("bitpix")
KEYWORD:    BITPIX
REFERENCE:  FITS Standard - version 4.0 - Appendix C
CLASS:      general
STATUS:     mandatory
HDU:        primary, groups, extension, array, image, ASCII-table, bintable,
VALUE:      integer
RANGE:      -64,-32,8,16,32,64
COMMENT:    bits per data value
DEFINITION: The value field shall contain an integer.  The absolute value is
used in computing the sizes of data structures. It shall specify the number of
bits that represent a data value (using a minus sign for floating point data).

Without argument fits_keyword provides the list of all FITS defined keywords (for the HDU types inplemented).

julia> fits_keyword()
FITS defined keywords:
(blanks) AUTHOR   BITPIX   BLANK    BLOCKED  BSCALE   BUNIT    BZERO            
CDELTn   COMMENT  CROTAn   CRPIXn   CRVALn   CTYPEn   DATAMAX  DATAMIN          
DATE     DATE-OBS END      EPOCH    EQUINOX  EXTEND   EXTLEVEL EXTNAME          
EXTVER   GCOUNT   GROUPS   HISTORY  INSTRUME NAXIS    NAXISn   OBJECT           
OBSERVER ORIGIN   PCOUNT   PSCALn   PTYPEn   PZEROn   REFERENC SIMPLE           
TBCOLn   TDIMn    TDISPn   TELESCOP TFIELDS  TFORMn   THEAP    TNULLn           
TSCALn   TTYPEn   TUNITn   TZEROn   XTENSION 

HDU options: 'primary', 'extension', 'array', 'image', 'ASCII-table', 'bintable'

reference: FITS Standard - version 4.0 - Appendix C

Specifying the FITS HDU type in fits_keyword the user obtains the restricted set of HDU-specific keywords.

julia> fits_keyword(hdutype="'PRIMARY '")
FITS defined keywords:
HDU type: 'primary'
- general
  - mandatory: BITPIX   END      NAXIS    NAXISn   SIMPLE
  - reserved : BLANK    BSCALE   BUNIT    BZERO    CDELTn   CROTAn   CRPIXn   
               CRVALn   CTYPEn   DATAMAX  DATAMIN  EXTEND
- bibliographic
  - mandatory:
  - reserved : AUTHOR   REFERENC
- commentary
  - mandatory:
  - reserved : (blanks) COMMENT  HISTORY
- observation
  - mandatory:
  - reserved : DATE-OBS EPOCH    EQUINOX  INSTRUME OBJECT   OBSERVER TELESCOP

HDU options: 'primary', 'extension', 'array', 'image', 'ASCII-table', 'bintable'

reference: FITS Standard - version 4.0 - Appendix C

By using the keyword "ALL" the user can dump the full list of keyword descriptions:

julia> fits_keyword("all")
FITS defined keywords:

KEYWORD:    (blank)
REFERENCE:  FITS Standard - version 4.0 - Appendix C
CLASS:      commentary
STATUS:     reserved
HDU:        primary, groups, extension, array, image, ASCII-table, bintable,
VALUE:      none
COMMENT:    descriptive comment
DEFINITION: Columns 1-8 contain ASCII blanks. This keyword has no associated 
value. Columns 9-80 may contain any ASCII text.  Any number of card images 
with blank keyword fields may appear in a header.
⋮
KEYWORD:    XTENSION
REFERENCE:  FITS Standard - version 4.0 - Appendix C
CLASS:      general
STATUS:     mandatory
HDU:        extension, array, image, ASCII-table, bintable,
VALUE:      string
COMMENT:    marks beginning of new HDU
DEFINITION: The value field shall contain a character string giving the name of 
the extension type. This keyword is mandatory for an extension header and must 
not appear in the primary header. For an extension that is not a standard 
extension, the type name must not be the same as that of a standard extension.
CamiFITS.fits_keyword — Method
fits_keyword(keyword::String [; msg=true])
fits_keyword([; hdutype="all" [, msg=true]])

Description of the reserved keywords of the FITS standard:

(blanks), ALL, AUTHOR, BITPIX, BLANK, BLOCKED, BSCALE, BUNIT, BZERO, CDELTn, COMMENT, CROTAn, CRPIXn, CRVALn, CTYPEn, DATAMAX, DATAMIN, DATE, DATE-OBS, END, EPOCH, EQUINOX, EXTEND, EXTLEVEL, EXTNAME, EXTVER, GCOUNT, GROUPS, HISTORY, INSTRUME, NAXIS, NAXISn, OBJECT, OBSERVER, ORIGIN, PCOUNT, PSCALn, PTYPEn, PZEROn, REFERENC, SIMPLE, TBCOLn, TDIMn, TDISPn, TELESCOP, TFIELDS, TFORMn, THEAP, TNULLn, TSCALn, TTYPEn, TUNITn, TZEROn, XTENSION,

where n = 1,...,nmax as specified for the keyword. Use the keyword "ALL" to dump the full list of keyword descriptions.

The descriptions are based on appendix C to FITS standard - version 4.0, which is not part of the standard but included for convenient reference.

julia> fits_keyword("naxisn");
KEYWORD:    NAXISn
REFERENCE:  FITS Standard - version 4.0 - Appendix C
CLASS:      general
STATUS:     mandatory
HDU:        primary, groups, extension, array, image, ASCII-table, bintable,
VALUE:      integer
RANGE:      [0:]
COMMENT:    size of the axis
DEFINITION: The value field of this indexed keyword shall contain a non-negative integer,  
representing the number of elements along axis n of a data array.
The NAXISn must be present for all values n = 1,...,NAXIS, and for no other values of n.   
A value of zero for any of the NAXISn signifies that no data follow the header in the HDU. 
If NAXIS is equal to 0, there should not be any NAXISn keywords.

julia> fits_keyword()
FITS defined keywords:
(blanks) AUTHOR   BITPIX   BLANK    BLOCKED  BSCALE   BUNIT    BZERO    
CDELTn   COMMENT  CROTAn   CRPIXn   CRVALn   CTYPEn   DATAMAX  DATAMIN  
DATE     DATE-OBS END      EPOCH    EQUINOX  EXTEND   EXTLEVEL EXTNAME  
EXTVER   GCOUNT   GROUPS   HISTORY  INSTRUME NAXIS    NAXISn   OBJECT   
OBSERVER ORIGIN   PCOUNT   PSCALn   PTYPEn   PZEROn   REFERENC SIMPLE   
TBCOLn   TDIMn    TDISPn   TELESCOP TFIELDS  TFORMn   THEAP    TNULLn   
TSCALn   TTYPEn   TUNITn   TZEROn   XTENSION

HDU options: 'primary', 'extension', 'array', 'image', 'ASCII-table', 'bintable'

reference: FITS Standard - version 4.0 - Appendix C
source

FITS terminology

CamiFITS.fits_terminology — Method
fits_terminology([term::String [; test=false]])

Description of the defined terms from FITS standard:

ANSI, ASCII, ASCII NULL, ASCII character, ASCII digit, ASCII space, ASCII text, Array, Array value, Basic FITS, Big endian, Bit, Byte, Card image, Character string, Conforming extension, Data block, Deprecate, Entry, Extension, Extension type name, FITS, FITS Support Office, FITS block, FITS file, FITS structure, Field, File, Floating point, Fraction, Group parameter value, HDU Header and Data Unit., Header, Header block, Heap, IAU, IAUFWG, IEEE, IEEE NaN, IEEE special values, Indexed keyword, Keyword name, Keyword record, MEF, Mandatory keyword, Mantissa, NOST, Physical value, Pixel, Primary HDU, Primary data array, Primary header, Random Group, Record, Repeat count, Reserved keyword, SIF, Special records, Standard extension.

julia> fits_terminology()
FITS defined terms:
ANSI, ASCII, ASCII NULL, ASCII character, ..., SIF, Special records, Standard extension.

julia> fits_terminology("FITS")
FITS:
Flexible Image Transport System.

julia> get(dictDefinedTerms, "FITS", nothing)
"Flexible Image Transport System."

julia> fits_terminology("p")
p:
Not one of the FITS defined terms.
suggestions: Physical value, Pixel, Primary HDU, Primary data array, Primary header.

see FITS Standard - https://fits.gsfc.nasa.gov/fits_standard.html
source