{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.826","julian_year":2026.826,"time":"2026-10-29T20:19:18.244Z","years_from_j2000":26.826,"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-4936","name":"IC 4936","class":"barred_spiral_galaxy_sbd","category":"galaxy","object_type":"Barred spiral galaxy SBd","mag":14.55,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":180992450.4130511,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":301.46750000000003,"dec_deg":-61.428527777777774,"epoch_ra_deg":302.049462,"epoch_dec_deg":-61.351266,"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":"Pavo","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4936","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":14.55,"h_mag":12.41,"j_mag":13.04,"k_mag":12.1,"redshift":0.013108,"hubble_type":"SBd","wikidata_id":"Q3681450","redshift_cmb":0.012832094597458932,"ngc_type_code":"G","uncertainties":{"distance_ly":[15886532.081294542,15886532.081294542]},"major_axis_arcmin":1.35,"minor_axis_arcmin":0.7,"position_angle_deg":12,"surface_brightness":23.36,"radial_velocity_km_s":3904},"designations":[{"catalog":"2MASX","designation":"2MASX J20055217-6125428"},{"catalog":"ESO","designation":"ESO 143-006"},{"catalog":"ESO","designation":"ESO 143-6"},{"catalog":"ESO-LV","designation":"ESO-LV 143-0060"},{"catalog":"IC","designation":"IC 4936"},{"catalog":"IRAS","designation":"IRAS F20015-6134"},{"catalog":"LEDA","designation":"LEDA 64088"},{"catalog":"PGC","designation":"PGC 64088"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. IC 4936 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ic-4936","bibtex":"@misc{spacecatalog_ic-4936,\n  author       = {{SpaceCatalog}},\n  title        = {{IC 4936}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/ic-4936},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}\n}","url":"https://spacecatalog.org/object/ic-4936","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."}