October 2nd
No Moon and good clear sky. Patrol imaging of M31 showed no bright new objects but after
several 600s images were stacked and subtracted from the reference image - a dim new object was seen.

The usual checks of PanSTARRS, DSS and SIMBAD plus minor planet centre showed no objects at that position.

I checked TNS, TCOP and previous nova records - nothing showed up.
A report was sent to TNS and the object was given the designation AT 2019 rsi

The subtraction image:

We now wait to see if a confirmation spectrum can be obtained.

3rd October

This compares the field taken with the 8 metre Subaru telescope with my image - clearly there is no star at that point:

October 9th

Nova AT 2019rsi somewhat brighter at 17.2:

The TESS space telescope has surveyed the region and produced some photometry and an updated position.

Previous RA, DEC: 00:42:23.520, +41:11:52.80 ….. my discovery coordinates
Updated RA, DEC: 00:42:23.529, +41:11:52.22 … TES coordinates

Some background on the space telescope TESS   Wikipedia   YouTube

October 16th

A bright moon rose quite early so image quality was hampered. Initial survey of M31 showed no new objects,
but stacking 5 x 600 second images showed a very dim blob on using the subtraction method.

Further investigation and lots of image enhancement showed a distinct object:

Minorplanets, Panstarrs, DSS, Simbad and Subaru searches showed no objects.

Subaru 8 metre scope image:

I contacted Kamil Hornoch in the Czech Republic. He confirmed the existence of the object.
After further searches of archive images, ATEL#13198 was published.

Kamil's image:

October 21st

AT 2019rsi has faded out of sight for my small 20cm scope.
I had given up hope of a confirmatory spectrum, but this ATEL came through today.

October 30th
There was a TNS announcement about a suspected nova in M31, AT 2019tsc
I looked through my images from the 29th October - sure enough, it was faintly visible.
Magnitude was around 19.5 which is at the limit for my equipment.

Stack of 9 x 600 seconds

Subtracted from the reference image.  AT 2019rsi still quite bright!

 Astrometrica gives m=19.4