{"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":"2026-08-27T23:10:15.636Z","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-221561","name":"HD 221561","class":"f8v_yellow_white_main_sequence_star","category":"star","object_type":"F8V yellow-white main-sequence star","mag":8.06,"mag_band":"V","abs_mag":3.414,"abs_mag_band":"V","distance_ly":277.1083293229441,"distance_method":"parallax","ra_deg":353.30021999999997,"dec_deg":-6.40059,"epoch_ra_deg":353.647237,"epoch_dec_deg":-6.252299,"epoch_moved_arcsec":3.348,"pm_ra_mas_yr":125.19,"pm_dec_mas_yr":10.35,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Aquarius","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-221561","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":4287227600,"mass_solar":1.207,"radius_solar":1.535,"spectral_type":"F8V","color_index_bv":0.536,"luminosity_solar":3.753185242379138,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":4.162,"surface_temperature_k":6086,"proper_motion_ra_mas_yr":125.19,"proper_motion_dec_mas_yr":10.35,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":2.8775},"designations":[{"catalog":"HD","designation":"HD 221561"},{"catalog":"HIP","designation":"HIP 116242"}],"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."}