{"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":"2026-09-06T02:37:18.152Z","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-17584","name":"16 Per","class":"f2iii_yellow_white_giant","category":"star","object_type":"F2III yellow-white giant","mag":4.22,"mag_band":"V","abs_mag":1.378,"abs_mag_band":"V","distance_ly":120.75385419120306,"distance_method":"parallax","ra_deg":42.645945,"dec_deg":38.318644,"epoch_ra_deg":43.071198,"epoch_dec_deg":38.429018,"epoch_moved_arcsec":5.975,"pm_ra_mas_yr":195.68,"pm_dec_mas_yr":-108.92,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Perseus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-17584","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"02506+3819","companions":[{"measured":2014,"magnitude":12.8,"components":"AB","discoverer_code":"BUP  34","separation_arcsec":75.8,"position_angle_deg":122},{"measured":2014,"magnitude":10.43,"components":"AC","discoverer_code":"STT 556","separation_arcsec":231.3,"position_angle_deg":149}],"spectral_type":"F2III","uncertainties":{"metallicity_fe_h":[0.21,0.21]},"color_index_bv":0.343,"luminosity_solar":24.479356661960658,"metallicity_fe_h":0.4,"radial_velocity_km_s":14,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":4.51,"surface_temperature_k":6847,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":195.68,"proper_motion_dec_mas_yr":-108.92,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"16 Per"},{"catalog":"HD","designation":"HD 17584"},{"catalog":"HIP","designation":"HIP 13254"},{"catalog":"HR","designation":"HR 840"}],"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."}