An Ophiuchus globular – Astronomy Now

Messier 14 (NGC 6402) is one in every of Ophiuchus’ seven Messier-tagged globular clusters, that are extremely dense balls of stars that may present hanging viewing. It kinds a trio with and tends to be quite unfairly overshadowed by the close by pairing of Messier 10 and Messier 12 (see Astronomy Now’s June 2021 deep-sky tour). Nonetheless, it’s simply one of many three most accessible of Ophiuchus’ crop from UK shores, and is vibrant sufficient to be readily snared by way of a pair of binoculars.

Methods to observe

Messier 14 lies simply south of the celestial equator, which implies that it peaks at an affordable altitude of 36 levels or so when darker skies return to the south of England within the final week of July. It’s straightforward to search out by sweeping with a pair of 10 × 50 binoculars round eight levels south-south-west of magnitude +2.7 Cebalrai (beta [β] Ophiuchi [Oph]), which itself lies the identical distance south-south-east of magnitude +2 Rasalhague (alpha [α] Oph).

With an built-in magnitude of +7.6, Messier 14 is a magnitude or so fainter than Messier 10 and 12, and, with an obvious diameter of 12’, it’s smaller too. Nonetheless, it’s intrinsically fairly a bit extra luminous, and can also be extra distant than its esteemed neighbours. Messier 14’s particular person stars shine comparatively faintly at round fourteenth-magnitude, owing to vital dimming (reddening) from interstellar mud and fuel within the aircraft of the Milky Manner, which knocks round two magnitudes off their brightness.

Thus, Messier 14’s member stars usually are not straightforward to resolve although moderate-aperture devices, although the globular has a quite unfastened class-VIII classification on the twelve-point Shapley–Sawyer system for cluster compactness. A 150mm (six-inch) telescope at excessive energy exhibits some granularity, whereas a 250mm (ten-inch) ’scope begins to resolve the cluster’s outlying stars. 

Novice photographs reveal that Messier 14 sports activities an east–west oriented, Jupiter-like oblateness, and has a noticeably golden solid in comparison with Messier 10 and 12.