{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T21:57:57.577Z","years_from_j2000":26.673,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"hlx-1","name":"HLX-1","class":"intermediate_mass_black_hole","category":"black_hole","object_type":"Intermediate-mass black hole","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":290000000,"distance_method":null,"ra_deg":17.61792,"dec_deg":-46.07286,"epoch_ra_deg":17.917007,"epoch_dec_deg":-45.929792,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":3.976819741396102e+34,"mass_msun":20000,"constellation":"Phoenix","discovered":"2009","featured":true,"url":"https://spacecatalog.org/object/hlx-1","radius_km":null,"radius_kind":null,"data_quality":null,"description":"The best candidate for an elusive intermediate-mass black hole — the missing link between stellar remnants and galactic giants, likely the stripped core of a dwarf galaxy.","properties":{"accretion":"transient","mass_solar":20000},"designations":[{"catalog":"Common name","designation":"HLX-1"}],"source":{"id":"curated","name":"SpaceCatalog curated data","url":"https://spacecatalog.org/releases","license":"CC-BY-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}