{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.654","julian_year":2026.654,"time":"2026-08-27T21:33:47.247Z","years_from_j2000":26.654,"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":"merak","name":"Merak","class":"a1ivps_white_subgiant","category":"star","object_type":"A1IVps white subgiant","mag":2.34,"mag_band":"V","abs_mag":0.399,"abs_mag_band":"V","distance_ly":79.74490819536605,"distance_method":"parallax","ra_deg":165.46015500000001,"dec_deg":56.382427,"epoch_ra_deg":165.864067,"epoch_dec_deg":56.238459,"epoch_moved_arcsec":2.355,"pm_ra_mas_yr":81.66,"pm_dec_mas_yr":33.74,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/merak","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wikidata_id":"Q13096","also_known_as":["Beta Ursae Majoris","The Celestial Rotating Jade","β UMa","β Ursae Majoris"],"spectral_type":"A1IVps","uncertainties":{"metallicity_fe_h":[0.251,0.251]},"color_index_bv":0.033,"luminosity_solar":60.311481961781745,"metallicity_fe_h":0.249,"wikipedia_article":"Merak (star)","radial_velocity_km_s":-12,"spectral_type_source":"SIMBAD (2010MNRAS.403.1089P, quality C)","surface_gravity_log_g":4,"surface_temperature_k":9552,"metallicity_fe_h_source":"Median of 5 spectroscopic determinations in 9 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":81.66,"proper_motion_dec_mas_yr":33.74,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"48 Beta UMa"},{"catalog":"Common name","designation":"Merak"},{"catalog":"Gliese","designation":"GJ 9343"},{"catalog":"HD","designation":"HD 95418"},{"catalog":"HIP","designation":"HIP 53910"},{"catalog":"HR","designation":"HR 4295"},{"catalog":"IRAS","designation":"IRAS 10588+5639"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-27T19:16:43.430Z","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."}