{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T15:50:21.724Z","years_from_j2000":26.678,"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-2948","name":"NGC 2948","class":"spiral_galaxy_sbc","category":"galaxy","object_type":"Spiral galaxy Sbc","mag":13.75,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":250955201.07036945,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":144.746625,"dec_deg":6.955444444444445,"epoch_ra_deg":145.101404,"epoch_dec_deg":6.834379,"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":"Leo","discovered":"1786","featured":false,"url":"https://spacecatalog.org/object/ngc-2948","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.75,"h_mag":10.27,"j_mag":10.86,"k_mag":9.93,"redshift":0.01661,"hubble_type":"Sbc","wikidata_id":"Q1102064","redshift_cmb":0.017727468727417595,"discovered_by":"William Herschel","ngc_type_code":"G","uncertainties":{"distance_ly":[17403689.338240445,17403689.338240445]},"major_axis_arcmin":1.43,"minor_axis_arcmin":0.78,"position_angle_deg":1,"surface_brightness":22.86,"radial_velocity_km_s":4938},"designations":[{"catalog":"2MASX","designation":"2MASX J09385921+0657199"},{"catalog":"IRAS","designation":"IRAS 09363+0710"},{"catalog":"LEDA","designation":"LEDA 27518"},{"catalog":"MCG","designation":"MCG +01-25-007"},{"catalog":"NGC","designation":"NGC 2948"},{"catalog":"PGC","designation":"PGC 27518"},{"catalog":"SDSS","designation":"SDSS J093859.18+065719.5"},{"catalog":"SDSS","designation":"SDSS J093859.19+065719.6"},{"catalog":"UGC","designation":"UGC 5141"}],"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."}