{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.811","julian_year":2026.811,"time":"2026-10-24T06:35:49.148Z","years_from_j2000":26.811,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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-27657","name":"θ Ret","class":"b_blue_white_star","category":"star","object_type":"B+ blue-white star","mag":5.88,"mag_band":"V","abs_mag":0.13,"abs_mag_band":"V","distance_ly":460.6727264220822,"distance_method":"parallax","ra_deg":64.41778500000001,"dec_deg":-63.255405,"epoch_ra_deg":64.496876,"epoch_dec_deg":-63.18841,"epoch_moved_arcsec":0.964,"pm_ra_mas_yr":5.48,"pm_dec_mas_yr":35.53,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Reticulum","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-27657","source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0","attribution":"HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.","commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"04177-6315","companions":[{"measured":2015,"magnitude":7.67,"components":null,"discoverer_code":"RMK   3","separation_arcsec":4.1,"position_angle_deg":2}],"mass_solar":3.189,"radius_solar":2.577,"spectral_type":"B+...","color_index_bv":-0.061,"luminosity_solar":77.26805850957021,"radial_velocity_km_s":3,"surface_gravity_log_g":3.988,"surface_temperature_k":12137,"proper_motion_ra_mas_yr":5.48,"proper_motion_dec_mas_yr":35.53,"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","bolometric_luminosity_solar":125.708},"designations":[{"catalog":"Bayer/Flamsteed","designation":"Theta Ret"},{"catalog":"HD","designation":"HD 27657"},{"catalog":"HIP","designation":"HIP 20020"},{"catalog":"HR","designation":"HR 1372"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. θ Ret [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-27657","bibtex":"@misc{spacecatalog_hd-27657,\n  author       = {{SpaceCatalog}},\n  title        = {{θ Ret}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-27657},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-27657","release":"DR1","doi":null},"references":[],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}