{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-02T23:14:42.438Z","years_from_j2000":26.671,"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-923","name":"NGC 923","class":"intermediate_spiral_galaxy_sabb","category":"galaxy","object_type":"Intermediate spiral galaxy SABb","mag":14.37,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":259302134.70789617,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":36.894333333333336,"dec_deg":41.977611111111116,"epoch_ra_deg":37.318014,"epoch_dec_deg":42.098213,"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":"Andromeda","discovered":"1878","featured":false,"url":"https://spacecatalog.org/object/ngc-923","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":14.37,"h_mag":10.85,"j_mag":11.52,"k_mag":10.47,"redshift":0.01902,"hubble_type":"SABb","wikidata_id":"Q1040231","redshift_cmb":0.018309178499376078,"discovered_by":"Édouard Stephan","ngc_type_code":"G","uncertainties":{"distance_ly":[17606085.041481633,17606085.041481633]},"major_axis_arcmin":0.78,"minor_axis_arcmin":0.55,"position_angle_deg":120,"surface_brightness":22.32,"radial_velocity_km_s":5648},"designations":[{"catalog":"2MASX","designation":"2MASX J02273463+4158392"},{"catalog":"IRAS","designation":"IRAS 02244+4145"},{"catalog":"LEDA","designation":"LEDA 9355"},{"catalog":"MCG","designation":"MCG +07-06-022"},{"catalog":"NGC","designation":"NGC 923"},{"catalog":"PGC","designation":"PGC 9355"},{"catalog":"UGC","designation":"UGC 1915"}],"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."}