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 to its lower-left (south-east). The open cluster Messier 52 is seen at the top of both frames. Both images have been cropped from the original. Images: Martin Mobberley.

MORE: astronomynow.com/2021/05/10/nova-cassiopeia-2021-suddenly-brightens-into-naked-eye-visibility/