{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T19:36:41.045Z","years_from_j2000":26.654,"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-49978","name":"HD 49978","class":"b7iii_iv_blue_white_giant","category":"star","object_type":"B7III/IV blue-white giant","mag":8.16,"mag_band":"V","abs_mag":1.065,"abs_mag_band":"V","distance_ly":856.0535122145603,"distance_method":"parallax","ra_deg":102.599685,"dec_deg":-16.030398,"epoch_ra_deg":102.901541,"epoch_dec_deg":-16.061121,"epoch_moved_arcsec":0.073,"pm_ra_mas_yr":-2.68,"pm_dec_mas_yr":0.64,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Canis Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-49978","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"06504-1602","companions":[{"measured":2016,"magnitude":11.19,"components":"AB","discoverer_code":"BU  898","separation_arcsec":3.3,"position_angle_deg":356},{"measured":2015,"magnitude":10.61,"components":"AC","discoverer_code":"BU  898","separation_arcsec":97.7,"position_angle_deg":282}],"spectral_type":"B7III/IV","color_index_bv":-0.042,"luminosity_solar":32.658783217233584,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1988MSS...C04....0H, quality D)","proper_motion_ra_mas_yr":-2.68,"proper_motion_dec_mas_yr":0.64},"designations":[{"catalog":"HD","designation":"HD 49978"},{"catalog":"HIP","designation":"HIP 32811"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T19:16:43.430Z","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."}