{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T12:13:57.499Z","years_from_j2000":26.667,"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-4817","name":"HD 4817","class":"k2_5ib_iicn_1_orange_supergiant","category":"star","object_type":"K2.5Ib-IICN-1 orange supergiant","mag":6.04,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":12.818264999999998,"dec_deg":61.805494,"epoch_ra_deg":13.221,"epoch_dec_deg":61.951621,"epoch_moved_arcsec":0.074,"pm_ra_mas_yr":-2.03,"pm_dec_mas_yr":-1.87,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cassiopeia","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-4817","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"spectral_type":"K2.5Ib-IICN-1","uncertainties":{"metallicity_fe_h":[0.135,0.135]},"color_index_bv":1.88,"metallicity_fe_h":-0.155,"radial_velocity_km_s":-6,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality C)","surface_gravity_log_g":0.66,"surface_temperature_k":4043,"metallicity_fe_h_source":"Median of 2 spectroscopic determinations in 3 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-2.03,"proper_motion_dec_mas_yr":-1.87,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 4817"},{"catalog":"HIP","designation":"HIP 3988"},{"catalog":"HR","designation":"HR 237"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}