{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.675","julian_year":2026.675,"time":"2026-09-04T13:01:45.652Z","years_from_j2000":26.675,"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-186408","name":"16 Cyg","class":"g1_5vb_yellow_main_sequence_star","category":"star","object_type":"G1.5Vb yellow main-sequence star","mag":5.99,"mag_band":"V","abs_mag":4.371,"abs_mag_band":"V","distance_ly":68.7514813280455,"distance_method":"parallax","ra_deg":295.45417499999996,"dec_deg":50.52506,"epoch_ra_deg":295.631385,"epoch_dec_deg":50.586283,"epoch_moved_arcsec":5.787,"pm_ra_mas_yr":-147.75,"pm_dec_mas_yr":-158.85,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cygnus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-186408","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"19418+5032","age_years":12002890000,"companions":[{"measured":2016,"magnitude":13,"components":"Aa,Ab","discoverer_code":"TRN   4","separation_arcsec":3.3,"position_angle_deg":207},{"measured":2025,"magnitude":6.23,"components":"AB","discoverer_code":"STFA 46","separation_arcsec":39.9,"position_angle_deg":133}],"mass_solar":0.956,"radius_solar":1.3,"spectral_type":"G1.5Vb","uncertainties":{"metallicity_fe_h":[0.049,0.049]},"color_index_bv":0.643,"luminosity_solar":1.5545331940607845,"metallicity_fe_h":0.09,"radial_velocity_km_s":-27.4,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality B)","surface_gravity_log_g":4.266,"surface_temperature_k":5666,"metallicity_fe_h_source":"Median of 31 spectroscopic determinations in 39 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-147.75,"proper_motion_dec_mas_yr":-158.85,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":1.5632},"designations":[{"catalog":"Bayer/Flamsteed","designation":"16 Cyg"},{"catalog":"Gliese","designation":"Gl 765.1A"},{"catalog":"HD","designation":"HD 186408"},{"catalog":"HIP","designation":"HIP 96895"},{"catalog":"HR","designation":"HR 7503"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","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."}