{"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":"2026-09-04T06:47:54.797Z","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-204155","name":"HD 204155","class":"f7v_yellow_white_main_sequence_star","category":"star","object_type":"F7V yellow-white main-sequence star","mag":8.49,"mag_band":"V","abs_mag":3.988,"abs_mag_band":"V","distance_ly":259.26594467994965,"distance_method":"parallax","ra_deg":321.678765,"dec_deg":5.441639,"epoch_ra_deg":322.015033,"epoch_dec_deg":5.555964,"epoch_moved_arcsec":7.947,"pm_ra_mas_yr":167.09,"pm_dec_mas_yr":-246.66,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Pegasus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-204155","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"21267+0527","age_years":8788486000,"companions":[{"measured":2000,"magnitude":15.4,"components":"AB","discoverer_code":"OSO 146","separation_arcsec":25,"position_angle_deg":309},{"measured":2000,"magnitude":16.5,"components":"AC","discoverer_code":"OSO 146","separation_arcsec":25.3,"position_angle_deg":49}],"mass_solar":1.031,"radius_solar":1.384,"spectral_type":"F7V","uncertainties":{"metallicity_fe_h":[0.128,0.128]},"color_index_bv":0.572,"luminosity_solar":2.212075776464127,"metallicity_fe_h":-0.67,"radial_velocity_km_s":-86.9,"spectral_type_source":"SIMBAD (1999MSS...C05....0H, quality C)","surface_gravity_log_g":4.191,"surface_temperature_k":5833,"metallicity_fe_h_source":"Median of 11 spectroscopic determinations in 16 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":167.09,"proper_motion_dec_mas_yr":-246.66,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":2.0018},"designations":[{"catalog":"HD","designation":"HD 204155"},{"catalog":"HIP","designation":"HIP 105888"}],"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."}