{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T18:37:54.287Z","years_from_j2000":26.673,"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-178971","name":"HD 178971","class":"f5iv_v_yellow_white_subgiant","category":"star","object_type":"F5IV-V yellow-white subgiant","mag":8.36,"mag_band":"V","abs_mag":3.251,"abs_mag_band":"V","distance_ly":342.96158507859866,"distance_method":"parallax","ra_deg":287.258085,"dec_deg":38.899858,"epoch_ra_deg":287.486469,"epoch_dec_deg":38.942089,"epoch_moved_arcsec":0.816,"pm_ra_mas_yr":9.01,"pm_dec_mas_yr":-29.23,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Lyra","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-178971","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":1821153800,"mass_solar":1.329,"radius_solar":1.474,"spectral_type":"F5IV-V","uncertainties":{"metallicity_fe_h":[0.097,0.097]},"color_index_bv":0.436,"luminosity_solar":4.361139713930646,"metallicity_fe_h":-0.045,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (2013MNRAS.434.1422M, quality C)","surface_gravity_log_g":4.165,"surface_temperature_k":6632,"metallicity_fe_h_source":"Median of 4 spectroscopic determinations in 6 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":9.01,"proper_motion_dec_mas_yr":-29.23,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":3.7679},"designations":[{"catalog":"HD","designation":"HD 178971"},{"catalog":"HIP","designation":"HIP 94071"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","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."}