{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.821","julian_year":2026.821,"time":"2026-10-27T21:43:30.202Z","years_from_j2000":26.821,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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-220652","name":"4 Cas","class":"m1_3_red_star","category":"star","object_type":"M1/3 red star","mag":4.96,"mag_band":"V","abs_mag":-1.95,"abs_mag_band":"V","distance_ly":785.9191278449958,"distance_method":"parallax","ra_deg":351.209385,"dec_deg":62.282806,"epoch_ra_deg":351.508067,"epoch_dec_deg":62.430854,"epoch_moved_arcsec":0.484,"pm_ra_mas_yr":12.24,"pm_dec_mas_yr":-13.25,"position_epoch_jyear":null,"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-220652","source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0","attribution":"HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.","commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"23248+6217","companions":[{"measured":2016,"magnitude":9.88,"components":"AB","discoverer_code":"H 6  24","separation_arcsec":96.4,"position_angle_deg":226},{"measured":2006,"magnitude":17.09,"components":"AE","discoverer_code":"ACA  19","separation_arcsec":122,"position_angle_deg":24},{"measured":2006,"magnitude":13.26,"components":"AG","discoverer_code":"ACA  19","separation_arcsec":151.8,"position_angle_deg":59},{"measured":2006,"magnitude":13.51,"components":"AF","discoverer_code":"ACA  19","separation_arcsec":191.5,"position_angle_deg":228},{"measured":2016,"magnitude":11.97,"components":"AC","discoverer_code":"H 6  24","separation_arcsec":215.8,"position_angle_deg":259}],"spectral_type":"M1/3","color_index_bv":1.676,"luminosity_solar":524.8074602497728,"radial_velocity_km_s":-37,"spectral_type_source":"SIMBAD (1935BSD...C01....0S, quality E)","proper_motion_ra_mas_yr":12.24,"proper_motion_dec_mas_yr":-13.25},"designations":[{"catalog":"Bayer/Flamsteed","designation":"4 Cas"},{"catalog":"HD","designation":"HD 220652"},{"catalog":"HIP","designation":"HIP 115590"},{"catalog":"HR","designation":"HR 8904"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. 4 Cas [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-220652","bibtex":"@misc{spacecatalog_hd-220652,\n  author       = {{SpaceCatalog}},\n  title        = {{4 Cas}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-220652},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-220652","release":"DR1","doi":null},"references":[{"bibcode":"1935BSD...C01....0S","ads_url":"https://ui.adsabs.harvard.edu/abs/1935BSD...C01....0S/abstract","quantity":"properties.spectral_type_source"}],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}