Closed tboch closed 1 month ago
I took some time to develop this API-like thing:
let aladin = A.aladin('#aladin-lite-div', {fov: 30, survey: "CDS/P/GALEXGR6/AIS/FUV", target: "280 +0", projection: "AIT"});
aladin.setOverlayImageLayer(
A.image(
"https://nova.astrometry.net/image/25038473?filename=M61.jpg",
{
name: "M61",
imgFormat: 'jpeg',
wcs: {
NAXIS: 0, // Minimal header
CTYPE1: 'RA---TAN', // TAN (gnomic) projection + SIP distortions
CTYPE2: 'DEC--TAN', // TAN (gnomic) projection + SIP distortions
EQUINOX: 2000.0, // Equatorial coordinates definition (yr)
LONPOLE: 180.0, // no comment
LATPOLE: 0.0, // no comment
CRVAL1: 185.445488837, // RA of reference point
CRVAL2: 4.47896032431, // DEC of reference point
CRPIX1: 588.995094299, // X reference pixel
CRPIX2: 308.307905197, // Y reference pixel
CUNIT1: 'deg', // X pixel scale units
CUNIT2: 'deg', // Y pixel scale units
CD1_1: -0.000223666022989, // Transformation matrix
CD1_2: 0.000296578064584, // no comment
CD2_1: -0.000296427555509, // no comment
CD2_2: -0.000223774308964, // no comment
NAXIS1: 1080, // Image width, in pixels.
NAXIS2: 705 // Image height, in pixels.
},
successCallback: (ra, dec, fov, image) => {
aladin.gotoRaDec(ra, dec);
aladin.setFoV(fov)
}
},
));
and the result
The WCS comes from astrometry.net. I removed the SIP corrections keywords as it is currently not yet supported by wcs-rs lib.
In a similar manner to support of FITS images, it would be great to be able to visualize PNG/JPEG images with astrometry information. In the long term, we might want to support astrometry serialized as AVM tags inside the PNG/JPEG, but to start with, we could have a new method allowing one to display a PNG/JPEG, passing the astrometry as a separate WCS JS dictionary.