Nova Cassiopeia 2021 suddenly brightens into naked-eye visibility – Astronomy Now
Nova Cas 2021, a ‘new star’ – a classical nova – discovered on 18 March 2021 in the northern constellation of Cassiopeia, has suddenly brightened in the past few days by around two magnitudes. It now shines at around magnitude +5.2, possibly within naked-eye range from a dark-sky UK location. Nova Cas 2021 (V1405 Cas) has brightened by around two magnitudes in the past few days. The image on the left shows it on 5 May 2021 at 10:23 UT, while the one on the right, taken on 8 May 2021 at 10:03 UT, shows the recent outburst. Compare its brightness with the magnitude +6.6 star HIP 115691 ...
Source: astronomynow.com