{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-02T22:18:14.250Z","years_from_j2000":26.671,"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-36591","name":"HD 36591","class":"b1iv_blue_white_subgiant","category":"star","object_type":"B1IV blue-white subgiant","mag":5.34,"mag_band":"V","abs_mag":-3.059,"abs_mag_band":"V","distance_ly":1560.5568327411474,"distance_method":"parallax","ra_deg":83.17229999999999,"dec_deg":-1.591831,"epoch_ra_deg":83.512218,"epoch_dec_deg":-1.572209,"epoch_moved_arcsec":0.058,"pm_ra_mas_yr":-2.03,"pm_dec_mas_yr":0.74,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Orion","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-36591","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"05327-0136","companions":[{"measured":2015,"magnitude":9.8,"components":null,"discoverer_code":"BU 1048","separation_arcsec":2.2,"position_angle_deg":355}],"radius_solar":6.872,"spectral_type":"B1IV","uncertainties":{"metallicity_fe_h":[0.118,0.118]},"color_index_bv":-0.188,"luminosity_solar":1457.4712612565295,"metallicity_fe_h":-0.06,"radial_velocity_km_s":34,"spectral_type_source":"SIMBAD (2023A&A...674A.212D, quality C)","surface_gravity_log_g":3.618,"surface_temperature_k":19456,"metallicity_fe_h_source":"Median of 6 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":-2.03,"proper_motion_dec_mas_yr":0.74,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 K GSP-Phot's temperature and extinction are degenerate"},"designations":[{"catalog":"HD","designation":"HD 36591"},{"catalog":"HIP","designation":"HIP 25980"},{"catalog":"HR","designation":"HR 1861"}],"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."}