{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.810","julian_year":2026.81,"time":"2026-10-23T23:27:02.238Z","years_from_j2000":26.81,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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":"cloverleaf-quasar","name":"Cloverleaf quasar","class":"quasar","category":"black_hole","object_type":"Quasar","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":66226109358.09513,"distance_method":"luminosity distance from a published redshift, flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":213.94271,"dec_deg":11.49539,"epoch_ra_deg":214.271582,"epoch_dec_deg":11.369841,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Boötes","discovered":"1988","featured":false,"url":"https://spacecatalog.org/object/cloverleaf-quasar","source":{"id":"curated","name":"SpaceCatalog curated data","url":"https://spacecatalog.org/releases","license":"CC-BY-4.0","attribution":null,"commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":"Lensing splits it into four images arranged like a clover. It was the first quasar found to contain carbon monoxide, which established that the cold molecular gas galaxies build stars out of was already in place ten billion years ago.","properties":{"redshift":2.51969,"accretion":"quasar"},"designations":[{"catalog":"Common name","designation":"Cloverleaf quasar"},{"catalog":"Common name","designation":"H1413+117"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. Cloverleaf quasar [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/cloverleaf-quasar","bibtex":"@misc{spacecatalog_cloverleaf-quasar,\n  author       = {{SpaceCatalog}},\n  title        = {{Cloverleaf quasar}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/cloverleaf-quasar},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from SpaceCatalog curated data.}\n}","url":"https://spacecatalog.org/object/cloverleaf-quasar","release":"DR1","doi":null},"references":[],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}