{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T14:35:06.537Z","years_from_j2000":26.681,"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-270754","name":"HD 270754","class":"b1_5ia_blue_white_supergiant","category":"star","object_type":"B1.5Ia blue-white supergiant","mag":11.27,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":71.768535,"dec_deg":-67.114753,"epoch_ra_deg":71.778292,"epoch_dec_deg":-67.065782,"epoch_moved_arcsec":0.053,"pm_ra_mas_yr":-0.81,"pm_dec_mas_yr":1.81,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Dorado","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-270754","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"radius_solar":26.059,"spectral_type":"B1.5Ia","color_index_bv":0.104,"variable_mag_max":11.171,"variable_mag_min":11.351,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1972A&AS....6..249A, quality C)","surface_gravity_log_g":2.877,"surface_temperature_k":19885,"proper_motion_ra_mas_yr":-0.81,"proper_motion_dec_mas_yr":1.81,"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 270754"},{"catalog":"HIP","designation":"HIP 22237"}],"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."}