{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.676","julian_year":2026.676,"time":"2026-09-05T01:17:17.985Z","years_from_j2000":26.676,"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-6447","name":"NGC 6447","class":"intermediate_spiral_galaxy_sabb","category":"galaxy","object_type":"Intermediate spiral galaxy SABb","mag":12.99,"mag_band":"V","abs_mag":null,"abs_mag_band":null,"distance_ly":315579779.5710936,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":266.5717916666667,"dec_deg":35.57197222222223,"epoch_ra_deg":266.809276,"epoch_dec_deg":35.561056,"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":"Hercules","discovered":"1864","featured":false,"url":"https://spacecatalog.org/object/ngc-6447","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":13.72,"h_mag":10.84,"j_mag":11.51,"k_mag":10.57,"v_mag":12.99,"redshift":0.02246,"hubble_type":"SABb","wikidata_id":"Q1145864","redshift_cmb":0.022218479085083676,"discovered_by":"Albert Marth","ngc_type_code":"G","uncertainties":{"distance_ly":[19069551.03308464,19069551.03308464]},"major_axis_arcmin":1.35,"minor_axis_arcmin":0.73,"position_angle_deg":150,"surface_brightness":22.64,"radial_velocity_km_s":6658},"designations":[{"catalog":"2MASX","designation":"2MASX J17461724+3534189"},{"catalog":"IRAS","designation":"IRAS 17445+3535"},{"catalog":"LEDA","designation":"LEDA 60829"},{"catalog":"MCG","designation":"MCG +06-39-019"},{"catalog":"NGC","designation":"NGC 6447"},{"catalog":"PGC","designation":"PGC 60829"},{"catalog":"UGC","designation":"UGC 10975"}],"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."}