{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.683","julian_year":2026.683,"time":"2026-09-07T08:40:27.093Z","years_from_j2000":26.683,"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-171242","name":"HD 171242","class":"g2_yellow_star","category":"star","object_type":"G2 yellow star","mag":7.98,"mag_band":"V","abs_mag":4.021,"abs_mag_band":"V","distance_ly":201.95439830031893,"distance_method":"parallax","ra_deg":277.87533,"dec_deg":45.009765,"epoch_ra_deg":278.06998,"epoch_dec_deg":45.025573,"epoch_moved_arcsec":9.949,"pm_ra_mas_yr":-101.55,"pm_dec_mas_yr":-358.76,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Lyra","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-171242","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"G2","color_index_bv":0.593,"luminosity_solar":2.1458531598843704,"radial_velocity_km_s":-3.6,"spectral_type_source":"SIMBAD (1985ApJS...59..197B, quality D)","surface_temperature_k":5879,"proper_motion_ra_mas_yr":-101.55,"proper_motion_dec_mas_yr":-358.76,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 171242"},{"catalog":"HIP","designation":"HIP 90813"}],"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."}