{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.682","julian_year":2026.682,"time":"2026-09-07T00:43:00.707Z","years_from_j2000":26.682,"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-133638","name":"T TrA","class":"b9iv_blue_white_subgiant","category":"star","object_type":"B9IV blue-white subgiant","mag":6.84,"mag_band":"V","abs_mag":0.546,"abs_mag_band":"V","distance_ly":591.9353391033187,"distance_method":"parallax","ra_deg":227.402385,"dec_deg":-68.721422,"epoch_ra_deg":228.026934,"epoch_dec_deg":-68.823986,"epoch_moved_arcsec":1.125,"pm_ra_mas_yr":-28.55,"pm_dec_mas_yr":-31.02,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Triangulum Australe","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-133638","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"15096-6843","companions":[{"measured":2016,"magnitude":15.5,"components":"AB","discoverer_code":"DON 714","separation_arcsec":8.9,"position_angle_deg":91},{"measured":2016,"magnitude":13.4,"components":"AC","discoverer_code":"DON 714","separation_arcsec":12.6,"position_angle_deg":179},{"measured":2016,"magnitude":14.3,"components":"AF","discoverer_code":"HDO 243","separation_arcsec":23.2,"position_angle_deg":37},{"measured":2016,"magnitude":11.28,"components":"AD","discoverer_code":"HDO 243","separation_arcsec":43.8,"position_angle_deg":39},{"measured":2016,"magnitude":12.29,"components":"AE","discoverer_code":"HDO 243","separation_arcsec":48.7,"position_angle_deg":318}],"spectral_type":"B9IV","color_index_bv":-0.019,"luminosity_solar":52.67444883319058,"variability_type":"CST:","variable_mag_max":6.827,"variable_mag_min":6.857,"variability_class":"Not variable (GCVS)","radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1975MSS...C01....0H, quality C)","variable_designation":"T TrA","proper_motion_ra_mas_yr":-28.55,"proper_motion_dec_mas_yr":-31.02},"designations":[{"catalog":"HD","designation":"HD 133638"},{"catalog":"HIP","designation":"HIP 74192"},{"catalog":"Variable star","designation":"T TrA"}],"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."}