{"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":"2026-09-01T12:10:54.433Z","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-181655","name":"HD 181655","class":"g5v_yellow_main_sequence_star","category":"star","object_type":"G5V yellow main-sequence star","mag":6.29,"mag_band":"V","abs_mag":4.267,"abs_mag_band":"V","distance_ly":82.80197192370508,"distance_method":"parallax","ra_deg":289.91253,"dec_deg":37.330539,"epoch_ra_deg":290.148149,"epoch_dec_deg":37.3782,"epoch_moved_arcsec":5.156,"pm_ra_mas_yr":-62.18,"pm_dec_mas_yr":-183.08,"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-181655","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"19196+3720","companions":[{"measured":2016,"magnitude":11.5,"components":"AB,C","discoverer_code":"DAM1457","separation_arcsec":34.6,"position_angle_deg":300}],"spectral_type":"G5V","uncertainties":{"metallicity_fe_h":[0.049,0.049]},"color_index_bv":0.676,"luminosity_solar":1.7108029875993274,"metallicity_fe_h":0.06,"radial_velocity_km_s":1.8,"spectral_type_source":"SIMBAD (2003AJ....126.2048G, quality C)","surface_gravity_log_g":4.51,"surface_temperature_k":5693,"metallicity_fe_h_source":"Median of 6 spectroscopic determinations in 8 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-62.18,"proper_motion_dec_mas_yr":-183.08,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Gliese","designation":"Gl 754.2"},{"catalog":"HD","designation":"HD 181655"},{"catalog":"HIP","designation":"HIP 94981"},{"catalog":"HR","designation":"HR 7345"}],"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."}