STCI 0.1.2

SpaceTelescopeColorImage tools for astronomy cutouts.

STCI

STCI stands for SpaceTelescopeColorImage.

STCI is a small astronomy image-composition tool for making display-ready color JPEGs from space telescope cutouts and other aligned mono images.

Installation

pip install STCI

The installed Python import module is STCI.

Example usage

mk_colorimg creates one color JPEG from either a 3-channel RGB array or three mono images in (R, G, B) order. For Euclid-style color images, the default mapping is NIR_J, NIR_Y, VIS.

from STCI import mk_colorimg

mk_colorimg(
    [
        "cutout_H.fits",    # R channel
        "cutout_VIS.fits",  # G channel
        "cutout_Y.fits",    # B channel
    ],
    output_jpg="target_mtf_vis_y_h.jpg",
    input_mode="raw",
)

For a NumPy RGB cube:

from STCI import mk_colorimg

mk_colorimg(rgb_array, output_jpg="target_color.jpg", input_mode="normalized")

Single-Band MTF Image

mk_monoimg creates one grayscale JPEG from a single mono image. It uses the same MTF-style stretch as mk_colorimg, but omits RGB-only steps such as color calibration, Lab luminance replacement, SCNR, and saturation.

from STCI import mk_monoimg

mk_monoimg(
    "cutout_VIS.fits",
    output_jpg="target_vis_mtf.jpg",
    input_mode="raw",
)

For a NumPy mono image:

from STCI import mk_monoimg

mk_monoimg(mono_array, output_jpg="target_mono.jpg", input_mode="normalized")

Download a Euclid Color Image

Euclidimg downloads Euclid DR1 VIS, NIR_Y, NIR_J, and NIR_H FITS cutouts, then renders one color JPEG using the NIR_J / NIR_Y / VIS channel order.

from STCI import Euclidimg

result = Euclidimg(
    ra=50.7163333,
    dec=-39.7693889,
    size=5.0,
    path="euclid_color",
    cred="Euclid/cred.txt",
    output_jpg="EUCLJ032251.92-394609.8.jpg",
    ReplaceL=True,
    RGB="auto",
)

print(result["jpg"])
print(result["fits"])
print(result["rgb_bands"])

Arguments:

• ra, dec: target coordinates in degrees.
• size: cutout radius in arcsec. For example, size=5.0 makes a 10" x 10" image.
• path: output directory for the FITS files and JPEG.
• cred: Euclid credentials file passed to astroquery.esa.euclid.
• output_jpg: optional JPEG filename written inside path.
• ReplaceL: if False, skip replacing the CIELab L* channel with the stretched blue luminosity channel.
• RGB: Euclid bands in (R, G, B) order. Use "auto" for the default available-band choice, or pass bands such as ("NIR_H", "NIR_Y", "VIS") or ("H", "Y", "VIS").

The returned dictionary contains the selected FITS paths and the final JPEG path. If the first overlapping mosaic tile for a band is empty or all zero, the downloader tries the next matching tile.

Download Euclid FITS Only

from Download_Euclid import EUC_download

fits_paths = EUC_download(
    ra=50.7163333,
    dec=-39.7693889,
    size=5.0,
    path="euclid_fits",
    cred="Euclid/cred.txt",
)