{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T14:55:17.318Z","years_from_j2000":26.678,"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-171779","name":"HD 171779","class":"g9iii_yellow_giant","category":"star","object_type":"G9III yellow giant","mag":5.38,"mag_band":"V","abs_mag":-1.078,"abs_mag_band":"V","distance_ly":638.2707449036479,"distance_method":"parallax","ra_deg":278.486235,"dec_deg":52.353517,"epoch_ra_deg":278.638151,"epoch_dec_deg":52.37354,"epoch_moved_arcsec":0.119,"pm_ra_mas_yr":-3.26,"pm_dec_mas_yr":3.03,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Draco","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-171779","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"18339+5221","companions":[{"measured":2017,"magnitude":6.4,"components":"AB","discoverer_code":"A  1377","separation_arcsec":0.2,"position_angle_deg":135},{"measured":2012,"magnitude":8.65,"components":"AB,C","discoverer_code":"STF2348","separation_arcsec":25.7,"position_angle_deg":271},{"measured":2005,"magnitude":11.2,"components":"AB,D","discoverer_code":"SLE 216","separation_arcsec":93.7,"position_angle_deg":338},{"measured":2005,"magnitude":12.2,"components":"AB,E","discoverer_code":"SLE 216","separation_arcsec":109.1,"position_angle_deg":232}],"spectral_type":"G9III","uncertainties":{"metallicity_fe_h":[0.046,0.046]},"color_index_bv":1.091,"luminosity_solar":235.07151159382903,"metallicity_fe_h":-0.12,"radial_velocity_km_s":-24,"spectral_type_source":"SIMBAD (1981ApJS...45..437A, quality C)","surface_gravity_log_g":2.31,"surface_temperature_k":4726,"metallicity_fe_h_source":"Median of 3 spectroscopic determinations in 3 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-3.26,"proper_motion_dec_mas_yr":3.03,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 171779"},{"catalog":"HIP","designation":"HIP 91013"},{"catalog":"HR","designation":"HR 6983"}],"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."}