A new nova, appearing in the northern constellation of Cassiopeia, can be seen with binoculars and small telescopes, but this transient object won’t stick around for long. Here’s how you can spot Nova V1405 Cas before it’s too late.
Amateur astronomer Yuji Nakamura from Kameyama City of Japan spotted the nova on March 18 at 7:10 p.m. local time and promptly reported his discovery to the National Astronomical Observatory of Japan (NAOJ). Astronomers using Kyoto University’s Seimei Telescope in Okayama Prefecture confirmed the nova at 4:40 a.m. the following day.
“This observation was carried out only half a day after the discovery, demonstrating fruitful collaboration between amateur astronomers and researchers,” announced the NAOJ in a statement. “Since we cannot predict when and in what direction novae will occur, discoveries by amateur astronomers contribute significantly to our understanding of the phenomena.”
Designated Nova V1405 Cas, the object was initially detected at 9.6 magnitude (too faint to be seen with the unaided eye), but it brightened significantly in the days following its discovery. As EarthSky reports, the nova is now glowing at around 7.6 magnitude, making it visible to binoculars and small telescopes and quite possibly the unaided eye (humans can spot celestial objects beginning at around 6.5 magnitude, but people might actually be able to spot the nova without equipment if the conditions are just right).
And yes, you should make the effort to see it if you can. Novae of this type, in which nuclear explosions cause the spectacular brightening of white dwarf stars, are common in the Milky Way, but visible novae are relatively rare. One of the last naked-eye novae, V1369 Cen, happened in 2013, and it was only visible in the southern hemisphere. Nova V1405 Cas is a transient object, and it will fade during the next several weeks and months.
EarthSky provides detailed information on how you can best spot V1405 Cas, but very simply, you should first locate the constellation Cassiopeia, which can be seen above the horizon when looking north-northwest after the Sun goes down (use a phone app like Sky Guide to help you locate celestial objects). Then, using the bottom two stars in Cassiopeia, draw a line to the right “for approximately the same distance as the two stars are apart from each other and start looking for a little star cluster known as M52,” EarthSky recommends. From here you should be able to spot the nova, which obviously won’t appear on star maps. Sky & Telescope recommends nightfall or just before dawn as the best times to view the new nova.
V1405 Cas is not to be confused with a Type Ia supernova, as it’s not a star that has outright exploded. This is a classic nova, involving a white dwarf and a main sequence star caught in a tight mutual orbit. The small, dense white dwarf pulls hydrogen away from its companion, and this hydrogen gets increasingly compact and hot. Eventually, nuclear fusion is triggered, causing the white dwarf to glow 50,000 to 100,000 times brighter than normal. The white dwarf survives these surface explosions, and the process begins anew.