{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.666","julian_year":2026.666,"time":"2026-09-01T04:57:56.148Z","years_from_j2000":26.666,"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-21901","name":"HD 21901","class":"k1ii_orange_bright_giant","category":"star","object_type":"K1II orange bright giant","mag":8.33,"mag_band":"V","abs_mag":1.663,"abs_mag_band":"V","distance_ly":702.9230928765494,"distance_method":"parallax","ra_deg":52.16148,"dec_deg":-61.18953,"epoch_ra_deg":52.293792,"epoch_dec_deg":-61.096126,"epoch_moved_arcsec":0.268,"pm_ra_mas_yr":9.49,"pm_dec_mas_yr":3.28,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Reticulum","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-21901","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":501804000,"mass_solar":2.704,"radius_solar":11.864,"spectral_type":"K1II","color_index_bv":1.176,"luminosity_solar":18.827818367346755,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1975MSS...C01....0H, quality C)","surface_gravity_log_g":2.249,"surface_temperature_k":4483,"proper_motion_ra_mas_yr":9.49,"proper_motion_dec_mas_yr":3.28,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":49.2801},"designations":[{"catalog":"HD","designation":"HD 21901"},{"catalog":"HIP","designation":"HIP 16194"}],"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."}