{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T06:23:11.916Z","years_from_j2000":26.674,"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-188668","name":"HD 188668","class":"k0_orange_star","category":"star","object_type":"K0 orange star","mag":7.22,"mag_band":"V","abs_mag":-0.06,"abs_mag_band":"V","distance_ly":931.8754114987494,"distance_method":"parallax","ra_deg":298.750575,"dec_deg":34.900604,"epoch_ra_deg":299.002468,"epoch_dec_deg":34.970941,"epoch_moved_arcsec":0.523,"pm_ra_mas_yr":3.35,"pm_dec_mas_yr":19.3,"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/hd-188668","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"19550+3454","age_years":250530030,"companions":[{"measured":2015,"magnitude":11.12,"components":"AC","discoverer_code":"GRF  12","separation_arcsec":89.5,"position_angle_deg":354},{"measured":2015,"magnitude":9.03,"components":"AB","discoverer_code":"GRF  12","separation_arcsec":125.5,"position_angle_deg":339},{"measured":2015,"magnitude":11.44,"components":"AD","discoverer_code":"GRF  12","separation_arcsec":128.3,"position_angle_deg":198}],"mass_solar":3.501,"radius_solar":18.128,"spectral_type":"K0","color_index_bv":1.14,"luminosity_solar":92.04495717531717,"radial_velocity_km_s":-27.3,"spectral_type_source":"SIMBAD (1993yCat.3135....0C, quality E)","surface_gravity_log_g":2.254,"surface_temperature_k":4747,"proper_motion_ra_mas_yr":3.35,"proper_motion_dec_mas_yr":19.3,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":137.3466},"designations":[{"catalog":"HD","designation":"HD 188668"},{"catalog":"HIP","designation":"HIP 98004"}],"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."}