{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T07:05:31.631Z","years_from_j2000":26.669,"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-42954","name":"HD 42954","class":"a6m_white_star","category":"star","object_type":"A6m white star","mag":5.86,"mag_band":"V","abs_mag":-0.189,"abs_mag_band":"V","distance_ly":528.616644558901,"distance_method":"parallax","ra_deg":93.61909499999999,"dec_deg":17.906353,"epoch_ra_deg":94.011304,"epoch_dec_deg":17.898631,"epoch_moved_arcsec":0.294,"pm_ra_mas_yr":-2.89,"pm_dec_mas_yr":-10.63,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Orion","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-42954","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"06145+1754","companions":[{"measured":2022,"magnitude":7.16,"components":null,"discoverer_code":"KUI  24","separation_arcsec":0.2,"position_angle_deg":146}],"spectral_type":"A6m","uncertainties":{"metallicity_fe_h":[0.15,0.15]},"color_index_bv":0.253,"luminosity_solar":103.65732567670052,"metallicity_fe_h":-0.03,"radial_velocity_km_s":29,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":3.73,"surface_temperature_k":8019,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":-2.89,"proper_motion_dec_mas_yr":-10.63,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 42954"},{"catalog":"HIP","designation":"HIP 29616"},{"catalog":"HR","designation":"HR 2214"}],"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."}