{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T13:50:35.382Z","years_from_j2000":26.67,"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":"hd-20807","name":"ζ² Ret","class":"g1v_yellow_main_sequence_star","category":"star","object_type":"G1V yellow main-sequence star","mag":5.24,"mag_band":"V","abs_mag":4.838,"abs_mag_band":"V","distance_ly":39.243787679634,"distance_method":"parallax","ra_deg":49.549635,"dec_deg":-62.506363,"epoch_ra_deg":49.69953,"epoch_dec_deg":-62.403006,"epoch_moved_arcsec":39.469,"pm_ra_mas_yr":1331.1,"pm_dec_mas_yr":646.84,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Reticulum","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-20807","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":4859749300,"mass_solar":0.997,"radius_solar":1.003,"spectral_type":"G1V","color_index_bv":0.6,"luminosity_solar":1.0111137119549065,"radial_velocity_km_s":11.5,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality B)","surface_gravity_log_g":4.352,"surface_temperature_k":5765,"proper_motion_ra_mas_yr":1331.1,"proper_motion_dec_mas_yr":646.84,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":0.9982},"designations":[{"catalog":"Bayer/Flamsteed","designation":"Zeta2 Ret"},{"catalog":"Gliese","designation":"Gl 138"},{"catalog":"HD","designation":"HD 20807"},{"catalog":"HIP","designation":"HIP 15371"},{"catalog":"HR","designation":"HR 1010"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}