Observer's guide
About NGC 6231
NGC 6231 (C76) is catalogued as an open cluster in Scorpius. Its J2000 position is RA 16:54:10, Dec -41:48:43, corresponding to 253.545 degrees RA and -41.8119 degrees Dec. The local catalogue places it about 6,000 light-years away. Its referenced angular extent is approximately 120 by 120 arcminutes.
Observing tips
This is rated as a very easy target at magnitude 2.6. It is associated with summer observing, with midnight placement typically strongest around May. From 52 degrees north its theoretical meridian altitude is about 0 degrees; local horizons and the live altitude chart determine the practical window.
Its brightness makes it a practical binocular or small-telescope candidate when it is well above the horizon.
What to expect
The SIMBAD classification for the matched source is OpC. A published radial velocity value is -28.2 km/s. The SIMBAD record currently connects it to 568 bibliographic references.
At roughly 120 arcminutes across, it favors a wide-field imaging setup. Use the listed 120 by 120 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.