{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T17:42:14.923Z","years_from_j2000":26.654,"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":"sadr","name":"Sadr","class":"f8ib_yellow_white_supergiant","category":"star","object_type":"F8Ib yellow-white supergiant","mag":2.23,"mag_band":"V","abs_mag":-6.518,"abs_mag_band":"V","distance_ly":1832.339354572355,"distance_method":"parallax","ra_deg":305.557095,"dec_deg":40.256679,"epoch_ra_deg":305.79697,"epoch_dec_deg":40.341953,"epoch_moved_arcsec":0.069,"pm_ra_mas_yr":2.43,"pm_dec_mas_yr":-0.93,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cygnus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/sadr","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"F8Ib","color_index_bv":0.673,"luminosity_solar":35253.318119588555,"radial_velocity_km_s":-8,"proper_motion_ra_mas_yr":2.43,"proper_motion_dec_mas_yr":-0.93},"designations":[{"catalog":"Bayer/Flamsteed","designation":"37 Gamma Cyg"},{"catalog":"Common name","designation":"Sadr"},{"catalog":"HR","designation":"HR 7796"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T16:03:54.983Z","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."}