{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.665","julian_year":2026.665,"time":"2026-08-31T21:57:23.476Z","years_from_j2000":26.665,"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-21085","name":"HD 21085","class":"a3ii_white_bright_giant","category":"star","object_type":"A3II white bright giant","mag":7.12,"mag_band":"V","abs_mag":-2.261,"abs_mag_band":"V","distance_ly":2452.303594307517,"distance_method":"parallax","ra_deg":51.518625,"dec_deg":49.745585,"epoch_ra_deg":51.999768,"epoch_dec_deg":49.839921,"epoch_moved_arcsec":0.016,"pm_ra_mas_yr":-0.26,"pm_dec_mas_yr":0.53,"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-21085","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"A3II","uncertainties":{"metallicity_fe_h":[0.08,0.08]},"color_index_bv":0.367,"luminosity_solar":698.8757961347106,"metallicity_fe_h":-0.1,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":2.1,"surface_temperature_k":8637,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":-0.26,"proper_motion_dec_mas_yr":0.53,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 21085"},{"catalog":"HIP","designation":"HIP 16001"}],"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."}