{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T15:38:21.766Z","years_from_j2000":26.667,"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-81817","name":"HD 81817","class":"k3ii_iii_orange_bright_giant","category":"star","object_type":"K3II-III orange bright giant","mag":4.28,"mag_band":"V","abs_mag":-3.141,"abs_mag_band":"V","distance_ly":994.3790412552529,"distance_method":"parallax","ra_deg":144.27226499999998,"dec_deg":81.326382,"epoch_ra_deg":145.18949,"epoch_dec_deg":81.20557,"epoch_moved_arcsec":0.617,"pm_ra_mas_yr":-16.77,"pm_dec_mas_yr":-15.95,"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-81817","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"K3II-III","color_index_bv":1.488,"luminosity_solar":1571.8098282039189,"metallicity_fe_h":0.09,"radial_velocity_km_s":-5,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality B)","surface_gravity_log_g":1.87,"surface_temperature_k":4030,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":-16.77,"proper_motion_dec_mas_yr":-15.95,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 81817"},{"catalog":"HIP","designation":"HIP 47193"},{"catalog":"HR","designation":"HR 3751"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}