{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.664","julian_year":2026.664,"time":"2026-08-31T14:53:52.574Z","years_from_j2000":26.664,"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":"ic-3455","name":"IC 3455","class":"spiral_galaxy_sbc","category":"galaxy","object_type":"Spiral galaxy Sbc","mag":16.71,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":null,"distance_method":null,"ra_deg":187.93562500000002,"dec_deg":25.786083333333334,"epoch_ra_deg":188.270558,"epoch_dec_deg":25.637793,"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":"Coma Berenices","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/ic-3455","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":16.71,"h_mag":13.03,"j_mag":13.88,"k_mag":12.9,"hubble_type":"Sbc","ngc_type_code":"G","major_axis_arcmin":0.59,"minor_axis_arcmin":0.31,"position_angle_deg":0,"surface_brightness":23.79},"designations":[{"catalog":"2MASX","designation":"2MASX J12314455+2547098"},{"catalog":"IC","designation":"IC 3455"},{"catalog":"SDSS","designation":"SDSS J123144.54+254709.9"},{"catalog":"SDSS","designation":"SDSS J123144.55+254709.8"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}