import (
    "os"
    
    "github.com/astrogo/fitsio"
)

r, err := os.Open("testdata/HorseHead.fits")
if err != nil {
    panic(err)
}
defer r.Close()

f, err := fitsio.Open(r)
if err != nil {
    panic(err)
}
defer f.Close()

printf("hdus: %d\n", len(f.HDUs()))
hdu := f.HDU(0)
printf("hdu: %q %v\n", hdu.Name(), hdu.Type())

img := hdu.(fitsio.Image)

img.Image()