{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.674","julian_year":2026.674,"time":"2026-09-04T06:22:50.094Z","years_from_j2000":26.674,"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-634","name":"NGC 634","class":"spiral_galaxy_sa","category":"galaxy","object_type":"Spiral galaxy Sa","mag":13.85,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":216599560.471983,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":24.577749999999998,"dec_deg":35.36483333333334,"epoch_ra_deg":24.964929,"epoch_dec_deg":35.501543,"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":"Triangulum","discovered":"1876","featured":false,"url":"https://spacecatalog.org/object/ngc-634","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.85,"h_mag":10.03,"j_mag":10.76,"k_mag":9.73,"redshift":0.01623,"hubble_type":"Sa","wikidata_id":"Q904230","redshift_cmb":0.015327958614236081,"discovered_by":"Édouard Stephan","ngc_type_code":"G","uncertainties":{"distance_ly":[16616342.403161976,16616342.403161976]},"major_axis_arcmin":1.77,"minor_axis_arcmin":0.61,"wikipedia_article":"NGC 634","position_angle_deg":167,"surface_brightness":23.35,"radial_velocity_km_s":4827},"designations":[{"catalog":"2MASX","designation":"2MASX J01381867+3521534"},{"catalog":"IRAS","designation":"IRAS F01354+3506"},{"catalog":"LEDA","designation":"LEDA 6059"},{"catalog":"MCG","designation":"MCG +06-04-048"},{"catalog":"NGC","designation":"NGC 634"},{"catalog":"PGC","designation":"PGC 6059"},{"catalog":"UGC","designation":"UGC 1164"}],"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."}