Observer's guide
About NGC 6254
NGC 6254 (M10) is catalogued as a globular cluster in Ophiucus. Its J2000 position is RA 16:57:08.99, Dec -04:05:57.6, corresponding to 254.2877 degrees RA and -4.1003 degrees Dec. The local catalogue places it about 14,400 light-years away. Its referenced angular extent is approximately 15.1 by 15.1 arcminutes.
Observing tips
This is rated as a moderate target at magnitude 6.6. It is associated with summer observing, with midnight placement typically strongest around May. From 52 degrees north its theoretical meridian altitude is about 33.9 degrees; local horizons and the live altitude chart determine the practical window.
A small telescope under reasonably dark skies is a good starting point; use the live altitude chart to choose its highest point.
What to expect
The SIMBAD classification for the matched source is GlC. A published radial velocity value is 74 km/s. The SIMBAD record currently connects it to 867 bibliographic references.
At roughly 15.1 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 15.1 by 15.1 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.