Marine mammals and sonar concern, but very little definitive information was known. In 1995 a comprehensive book on the relation between marine mammals and noise had been published, and it did not even mention strandings. In 2013, research showed beaked whales were highly sensitive to mid-frequency active sonar. Blue whales have also been shown to flee from the source of mid-frequency sonar, while naval use of mid- and high- frequency side-scan sonar was deemed 'the most probable cause' of a mass stranding of around 50 short-beaked common dolphin ("Delphinus delphis") on 9 June 2008 in Falmouth Bay, Cornwall, UK. There was anecdotal evidence from
Delphinus bounds of the constellation since 1992. HR Delphini was a nova that brightened to magnitude 3.5 in December 1967. A nova was discovered by amateur astronomer Koichi Itagaki, Nova Delphini 2013. Giants within our galaxy in Delphinus aside from Delta, Gamma and Epsilon include: Its rich Milky Way star field means many modestly deep-sky objects. NGC 6891 is a planetary nebula of magnitude 10.5; another is NGC 6905 or the Blue Flash nebula. NGC 6934 is a globular cluster of magnitude 9.75. At a distance of about 185,000 light-years, the globular cluster NGC 7006 is at the outer reaches of