{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.679","julian_year":2026.679,"time":"2026-09-06T03:52:20.497Z","years_from_j2000":26.679,"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-206826","name":"78 μ¹ Cyg","class":"f6v_f3v_yellow_white_main_sequence_star","category":"star","object_type":"F6V+F3V yellow-white main-sequence star","mag":4.49,"mag_band":"V","abs_mag":2.755,"abs_mag_band":"V","distance_ly":72.52739371287223,"distance_method":"parallax","ra_deg":326.03565000000003,"dec_deg":28.742632,"epoch_ra_deg":326.335236,"epoch_dec_deg":28.863813,"epoch_moved_arcsec":9.496,"pm_ra_mas_yr":260.33,"pm_dec_mas_yr":-242.73,"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-206826","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"21441+2845","age_years":2671089600,"companions":[{"measured":2023,"magnitude":6.18,"components":"AB","discoverer_code":"STF2822","separation_arcsec":1.5,"position_angle_deg":325},{"measured":2012,"magnitude":12.93,"components":"AC","discoverer_code":"STF2822","separation_arcsec":76.6,"position_angle_deg":292},{"measured":2012,"magnitude":12.64,"components":"AF","discoverer_code":"FYM  25","separation_arcsec":111.5,"position_angle_deg":72},{"measured":2012,"magnitude":13.77,"components":"AG","discoverer_code":"FYM  25","separation_arcsec":168.1,"position_angle_deg":73},{"measured":2019,"magnitude":6.94,"components":"AD","discoverer_code":"STF2822","separation_arcsec":197,"position_angle_deg":43}],"mass_solar":1.399,"radius_solar":1.907,"spectral_type":"F6V+F3V","uncertainties":{"metallicity_fe_h":[0.03,0.03]},"color_index_bv":0.512,"luminosity_solar":6.8865229634427605,"metallicity_fe_h":-0.19,"radial_velocity_km_s":15.8,"spectral_type_source":"SIMBAD (1935ApJ....81..187A, quality C)","surface_gravity_log_g":3.986,"surface_temperature_k":6340,"metallicity_fe_h_source":"Median of 2 spectroscopic determinations in 2 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":260.33,"proper_motion_dec_mas_yr":-242.73,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":5.3664},"designations":[{"catalog":"Bayer/Flamsteed","designation":"78 Mu1 Cyg"},{"catalog":"Gliese","designation":"Gl 836.6A"},{"catalog":"HD","designation":"HD 206826"},{"catalog":"HIP","designation":"HIP 107310"},{"catalog":"HR","designation":"HR 8309"}],"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."}