{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.812","julian_year":2026.812,"time":"2026-10-24T12:57:51.748Z","years_from_j2000":26.812,"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-4583","name":"IC 4583","class":"spiral_galaxy_sab","category":"galaxy","object_type":"Spiral galaxy Sab","mag":14.78,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":301679202.82885265,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":236.59141666666667,"dec_deg":23.80902777777778,"epoch_ra_deg":236.8822,"epoch_dec_deg":23.724835,"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":"Serpens","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-4583","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":14.78,"h_mag":10.74,"j_mag":11.44,"k_mag":10.41,"redshift":0.0209,"hubble_type":"Sab","wikidata_id":"Q3682584","redshift_cmb":0.02125493686799551,"ngc_type_code":"G","uncertainties":{"distance_ly":[18693180.86853617,18693180.86853617]},"major_axis_arcmin":1.21,"minor_axis_arcmin":0.28,"position_angle_deg":39,"surface_brightness":23.23,"radial_velocity_km_s":6201},"designations":[{"catalog":"2MASX","designation":"2MASX J15462194+2348327"},{"catalog":"IC","designation":"IC 4583"},{"catalog":"LEDA","designation":"LEDA 55999"},{"catalog":"MCG","designation":"MCG +04-37-032"},{"catalog":"PGC","designation":"PGC 55999"},{"catalog":"SDSS","designation":"SDSS J154621.93+234832.5"},{"catalog":"SDSS","designation":"SDSS J154621.94+234832.5"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. IC 4583 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/ic-4583","bibtex":"@misc{spacecatalog_ic-4583,\n  author       = {{SpaceCatalog}},\n  title        = {{IC 4583}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/ic-4583},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from OpenNGC.}\n}","url":"https://spacecatalog.org/object/ic-4583","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."}