NOVA Sco 1860; T Sco; AAVSO 1611-22C: - Object Coordinates: RAJ2000.0 16h 17m 02.83s - Dec J2000.0 -22° 58' 31.3" [SIMBAD] - Magnitudine: 6.8^ (v); Surface Brightness: --.-^ - Object Size: --- - Position Angle: ---° - Object Classification: NOVA; Redshift z(~): --- - Spectrum: --- -- Morphological Type: Nova --- : La famosa stella che oggi viene chiamata T Scorpii è stata per molti anni l'unica Nova scoperta all'interno degli ammassi globulari. Soltanto in un altro caso ad oggi conosciuto sappiamo dell'osservazione di una stella nova vista all'interno di un ammasso globulare ed è quello del 1938 osservato nell'ammasso globulare M14 in Ophiuchus, but remained undetected until 1964. Two such cases favor the probability that these stars were true cluster members, and not merely foreground stars.
The Nova of 1860 was first seen by W. Auwers at Berlin on May 21, at about the 7th magnitude. Auwers had observed the cluster three nights previously when, according to Miss Agnes Clerke, it presented its usual appearance of a some what hazy ball of light, brightening gradually inward, and resolvable with difficulty into separate stellar points together constituting a closely-packed and most likely excessively remote globular cluster "...he saw that these minnows now] had a triton in their midst. A seventh magnitude star shone close to the center of the stellar group...". The nova was independently found by N. Pogson on May 28, when the magnitude was estimated to be about 7.6^; he found the new star to be nearly central in the cluster, slight lyeless than 5" from the geometrical center, The magnitude stimates are undoubtedly rather uncertain owing to the bright background of the cluster; the following figures were published by Dr. Auwers:

May 21= 7.0^; May 22= 7.0^; May 25= 7.8^; June 3= 9.2^; June 12= 10.0^; June 16= 10.5^.

Pogson's account states that by June 10 the stellar appearance had nearly vanished, but the cluster yet shone with unusual brilliancy and a marked central condensation", The fading was considerably more rapid than usual for novae in general; the star decreased by 2 magnitudes in the first 11 days. No observations after mid-June are recorded. In the Astronomical Journal in 1902, J. Baxendell stated that a re-brightening of the nova to the 9th magnitude had been observed by Pogson in early 1864; but it still seems uncertain whether this report, never published by Pogson, actually refers to the Nova T Scorpii. J. Schmidt at Athens kept a close watch on M 80 for more than 10 years after the outburst and never saw a reappearance of the star. If a true member of the cluster, the nova had an actual peak luminosity of about -8.5, close to 200,000 times the light of the Sun, and about equal to the combined light of all the rest of the cluster stars put together: The question of the probability of collisions between stars in a dense globular cluster has been examined by J.G. Hills and C. A. Day (1976) at the University of Michigan. In a globular containing a million stars, some 335 collisions have probably occurred during the cluster's 12-billion year lifetime. In the case of M 80 itself, one of the densest globulars known, the probability rises to about 2700 star collisions since the cluster was formed. Owing to the relatively low velocity of collision, it is uncertain whether a nova outburst might result from such an event; the analysis suggests that the colliding stars "will tend to coalesce, with only a small fraction of their combined massescaping". In M 80 it seems likely that more than 1.4% of the cluster stars have experienced such an event in the group's long history, and that the normal pattern of stellar evolution of such stars has been drastically altered.