The astronomer’s telegram reported the discovery of a nova, V0419 Mus, in the constellation Musca on May 24 by K. Stanek of the All-Sky Automated Survey for Supernovae (ASAS-SN). Archival data showed the outburst started on May 10. AAVSO sent out an alert notice on May 29.
Last night was the first opportunity I’d had to attempt an observation. Although the sky conditions were far from ideal, between clouds I obtained enough data (19 cloud-free FITS files with Seestar S50) to carry out photometry.
The field containing V0419 Mus (aka Nova Mus 2026) and photometry in progress (nova in cross hairs and reference stars in green at top right) is shown above.
Another faint star in the field led to the need for careful photometry aperture sizing:
The result of photometry is shown in the plot below (under the cross hairs): a visual (Tri-Color Green) magnitude of 7.966 (with error 0.058). The visual (Johnson V) observation about 3.5 hours immediately before of 7.943 (with error 0.024) was submitted several hours after mine by an observer in Queensland, and the visual magnitude 8 (using eyeball + binoculars or telescope) was made about 4 hours later by an observer in Botswana.
There were only around 70 visual band observations as of around midday today, not surprising given the weather and the nova’s very southern declination, along with about the same number of observations in red and blue bands.
Nova light curves often appear quite non-descript and messy early on.
The following 1.2 degree finder chart needs to be rotated about 45 degrees clockwise to match the Seestar images above:
It’s a fairly sparse patch of sky.
The AAVSO Variable Star Index VSX record gives more detail about the nova including visual band magnitude range, currently 19 to 7.7. Novae often have pre-eruption magnitudes of 19 or dimmer.
We’ll see what happens next with V0419 Mus, whether it brightens again or continues to decline.