{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.816","julian_year":2026.816,"time":"2026-10-25T22:39:12.630Z","years_from_j2000":26.816,"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":"ic-2531","name":"IC 2531","class":"spiral_galaxy_sc","category":"galaxy","object_type":"Spiral galaxy Sc","mag":12.22,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":131170561.88782386,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":149.98237499999996,"dec_deg":-29.616972222222223,"epoch_ra_deg":150.284233,"epoch_dec_deg":-29.746086,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Antlia","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-2531","source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0","attribution":"OpenNGC, Mattia Verga (github.com/mattiaverga/OpenNGC). 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":{"b_mag":12.89,"h_mag":8.84,"j_mag":9.61,"k_mag":8.51,"v_mag":12.22,"redshift":0.008229,"hubble_type":"Sc","wikidata_id":"Q3689114","redshift_cmb":0.009324326564718044,"ngc_type_code":"G","uncertainties":{"distance_ly":[15036431.79268441,15036431.79268441]},"major_axis_arcmin":6.55,"minor_axis_arcmin":0.6,"wikipedia_article":"IC 2531","position_angle_deg":74,"surface_brightness":23.91,"radial_velocity_km_s":2457},"designations":[{"catalog":"2MASX","designation":"2MASX J09595554-2937040"},{"catalog":"ESO","designation":"ESO 435-025"},{"catalog":"ESO","designation":"ESO 435-25"},{"catalog":"ESO-LV","designation":"ESO-LV 435-0250"},{"catalog":"IC","designation":"IC 2531"},{"catalog":"IRAS","designation":"IRAS 09576-2922"},{"catalog":"LEDA","designation":"LEDA 28909"},{"catalog":"MCG","designation":"MCG -05-24-015"},{"catalog":"PGC","designation":"PGC 28909"},{"catalog":"UGCA","designation":"UGCA 191"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. IC 2531 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ic-2531","bibtex":"@misc{spacecatalog_ic-2531,\n  author       = {{SpaceCatalog}},\n  title        = {{IC 2531}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/ic-2531},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}\n}","url":"https://spacecatalog.org/object/ic-2531","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."}