{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T13:31:10.363Z","years_from_j2000":26.681,"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":"twin-quasar","name":"Twin Quasar","class":"quasar","category":"black_hole","object_type":"Quasar","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":32718661077.951004,"distance_method":"luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":150.33622,"dec_deg":55.89878,"epoch_ra_deg":150.791665,"epoch_dec_deg":55.769655,"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":null,"mass_msun":null,"constellation":"Ursa Major","discovered":"1979","featured":true,"url":"https://spacecatalog.org/object/twin-quasar","radius_km":null,"radius_kind":null,"data_quality":null,"description":"The first gravitational lens ever identified. Two quasars six arcseconds apart had spectra that matched line for line, and the explanation was that they are one quasar whose light reaches us along two paths around a galaxy in between.","properties":{"redshift":1.414,"accretion":"quasar"},"designations":[{"catalog":"Common name","designation":"QSO 0957+561"},{"catalog":"Common name","designation":"Twin Quasar"}],"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."}