Observer's guide
About NGC 6397
NGC 6397 (C86) is catalogued as a globular cluster in Ara. Its J2000 position is RA 17:40:42, Dec -53:40:28, corresponding to 265.1754 degrees RA and -53.6743 degrees Dec. The local catalogue places it about 7,800 light-years away. Its referenced angular extent is approximately 25.7 by 25.7 arcminutes.
Observing tips
StarWatchr rates this as an easy target at magnitude 5.7. It is associated with summer observing, with midnight placement typically strongest around June. 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 GlC. A published radial velocity value is 18.4 km/s. The SIMBAD record currently connects it to 2123 bibliographic references.
Its roughly 25.7 arcminute span suits a medium field of view. Use the listed 25.7 by 25.7 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.