Flexible Image Transport System (FITS) support for Julia
Note: The Libcfitsio submodule has been moved to CFITSIO.jl and will be deprecated in a future release.
For more in-depth usage and examples, see the documentation. Here, we provide an example where we read a sample fits file provided by NASA.
julia> using FITSIO, Downloads
julia> url = "https://fits.gsfc.nasa.gov/samples/FOSy19g0309t_c2f.fits";
julia> fname = Downloads.download(url, basename(url))
julia> f = FITS(fname, "r")
File: FOSy19g0309t_c2f.fits
Mode: "r" (read-only)
HDUs: Num Name Type
1 Image
2 y19g0309t.c2h.tab ASCIITable
julia> f[1]
File: FOSy19g0309t_c2f.fits
HDU: 1
Mode: read-only
Type: Image
Datatype: Float32
Datasize: (2064, 2)
# read an image from disk
julia> data = read(f[1]);
# read just a subset of image
julia> read(f[1], 1:4, :)
4×2 Matrix{Float32}:
2.48511f-15 1.36115f-15
1.56953f-15 1.10982f-15
0.0 0.0
1.12148f-15 9.71231f-16
# Get info about a table
julia> f[2]
File: FOSy19g0309t_c2f.fits
HDU: 2 (name=y19g0309t.c2h.tab)
Type: ASCIITable
Rows: 2
Columns: Name Type TFORM
CRVAL1 Float64 D25.16
CRPIX1 Float64 E15.7
CD1_1 Float64 E15.7
DATAMIN Float64 E15.7
DATAMAX Float64 E15.7
RA_APER Float64 D25.16
DEC_APER Float64 D25.16
FILLCNT Int32 I11
ERRCNT Int32 I11
FPKTTIME Float64 D25.16
LPKTTIME Float64 D25.16
CTYPE1 String A8
APER_POS String A8
PASS_DIR Int32 I11
YPOS Float64 E15.7
YTYPE String A4
EXPOSURE Float64 E15.7
X_OFFSET Float64 E15.7
Y_OFFSET Float64 E15.7
# Read a column from the table:
julia> data = read(f[2], "CD1_1")
2-element Vector{Float64}:
1.0
1.0
# Read the entire header into memory
julia> header = read_header(f[1]);
julia> header["NAXIS1"] # get value by keyword
2064
# Read single keys into memory
julia> read_key(f[1], 4) # by position
("NAXIS1", 2064, "")
julia> read_key(f[1], "NAXIS1") # by keyword
(2064, "")
# write data to file
julia> FITS("new_file.fits", "w") do f
write(f, data; header)
end