{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.673","julian_year":2026.673,"time":"2026-09-03T18:03:13.489Z","years_from_j2000":26.673,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, 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. 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":"ngc-4307","name":"NGC 4307","class":"barred_spiral_galaxy_sbb","category":"galaxy","object_type":"Barred spiral galaxy SBb","mag":12.71,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":61851372.4887022,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":185.52366666666666,"dec_deg":9.04363888888889,"epoch_ra_deg":185.865747,"epoch_dec_deg":8.894654,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Virgo","discovered":"1881","featured":false,"url":"https://spacecatalog.org/object/ngc-4307","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":12.71,"h_mag":9,"j_mag":9.72,"k_mag":8.72,"redshift":0.00328,"hubble_type":"SBb","wikidata_id":"Q1110580","redshift_cmb":0.00441308493707937,"discovered_by":"Christian Heinrich Friedrich Peters","ngc_type_code":"G","uncertainties":{"distance_ly":[14244775.106032645,14244775.106032645]},"major_axis_arcmin":3.44,"minor_axis_arcmin":0.81,"wikipedia_article":"NGC 4307","position_angle_deg":24,"surface_brightness":23.14,"radial_velocity_km_s":982},"designations":[{"catalog":"2MASX","designation":"2MASX J12220562+0902367"},{"catalog":"IRAS","designation":"IRAS 12195+0919"},{"catalog":"IRAS","designation":"IRAS F12195+0919"},{"catalog":"LEDA","designation":"LEDA 40033"},{"catalog":"MCG","designation":"MCG +02-32-012a"},{"catalog":"NGC","designation":"NGC 4307"},{"catalog":"PGC","designation":"PGC 40033"},{"catalog":"SDSS","designation":"SDSS J122205.68+090237.0"},{"catalog":"UGC","designation":"UGC 7431"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T19:50:56.720Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}