{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T04:53:14.197Z","years_from_j2000":26.669,"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-77996","name":"18 ω Hya","class":"k2ii_iii_orange_bright_giant","category":"star","object_type":"K2II-III orange bright giant","mag":4.99,"mag_band":"V","abs_mag":-2.204,"abs_mag_band":"V","distance_ly":896.0340871514566,"distance_method":"parallax","ra_deg":136.49319,"dec_deg":5.092316,"epoch_ra_deg":136.846242,"epoch_dec_deg":4.985093,"epoch_moved_arcsec":0.585,"pm_ra_mas_yr":-18.97,"pm_dec_mas_yr":-11.01,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Hydra","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-77996","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"mass_solar":4.901,"radius_solar":39.93,"spectral_type":"K2II-III","uncertainties":{"metallicity_fe_h":[0.151,0.151]},"color_index_bv":1.189,"luminosity_solar":663.1320218835529,"metallicity_fe_h":0,"radial_velocity_km_s":25,"spectral_type_source":"SIMBAD (1952ApJ...116..122R, quality C)","surface_gravity_log_g":1.931,"surface_temperature_k":4861,"metallicity_fe_h_source":"Median of 3 spectroscopic determinations in 4 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-18.97,"proper_motion_dec_mas_yr":-11.01,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":477.4176},"designations":[{"catalog":"Bayer/Flamsteed","designation":"18 Omega Hya"},{"catalog":"HD","designation":"HD 77996"},{"catalog":"HIP","designation":"HIP 44659"},{"catalog":"HR","designation":"HR 3613"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}