{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.844","julian_year":2026.844,"time":"2026-11-05T10:31:53.541Z","years_from_j2000":26.844,"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-204770","name":"7 Cep","class":"b7v_blue_white_main_sequence_star","category":"star","object_type":"B7V blue-white main-sequence star","mag":5.42,"mag_band":"V","abs_mag":-1.543,"abs_mag_band":"V","distance_ly":805.324453850009,"distance_method":"parallax","ra_deg":321.9422617610958,"dec_deg":66.809096,"epoch_ra_deg":322.067503,"epoch_dec_deg":66.926106,"epoch_moved_arcsec":0.62,"pm_ra_mas_yr":-10.22,"pm_dec_mas_yr":-20.72,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cepheus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-204770","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":"21278+6649","companions":[{"measured":2017,"magnitude":9.2,"components":null,"discoverer_code":"DCH 115","separation_arcsec":0.6,"position_angle_deg":321}],"mass_solar":4.151,"radius_solar":5.388,"spectral_type":"B7V","uncertainties":{"distance_ly":[39.69908961949586,44.04117754662817]},"color_index_bv":-0.099,"luminosity_solar":360.7447338641916,"radial_velocity_km_s":3,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":3.589,"surface_temperature_k":11879,"proper_motion_ra_mas_yr":-10.22,"proper_motion_dec_mas_yr":-20.72,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 K GSP-Phot's temperature and extinction are degenerate","bolometric_luminosity_solar":519.8714},"designations":[{"catalog":"Bayer/Flamsteed","designation":"7 Cep"},{"catalog":"HD","designation":"HD 204770"},{"catalog":"HIP","designation":"HIP 105972"},{"catalog":"HR","designation":"HR 8227"}],"updated_at":"2026-11-04T19:31:31.075Z","citation":{"plain":"SpaceCatalog. 7 Cep [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-204770","bibtex":"@misc{spacecatalog_hd-204770,\n  author       = {{SpaceCatalog}},\n  title        = {{7 Cep}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-204770},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-204770","release":"DR1","doi":null},"references":[],"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."}