It is in Sagittarius.
We need accurate astrometry because there is some ambiguity about the possible progenitor if the object turns out to be real.
There is a 20.3 Gmag. blue star 0.6" away which would indicate a too large amplitude for a dwarf nova, and a brighter 18.0 Vmag. star 2" away which would make it a possible UGWZ regarding amplitude.
I’ve corrected my astrometry on the TOCP page. From my measurements, it appears as though the transient is within 0.12" of the 20.3 Gmag blue star (Gaia 4051881016197528192). I used the Seestar S50 for some multi-colour photometry and it does appear red (B-V = approx. 1.2), recognising that standard filters have not been used.
@Spectroscopy Spectroscopic confirmation needed ASAP! This target is bright (now 9.0V and likely brightening) so please go for it. A low-resolution spectrum would be sufficient to determine whether or not it is a nova. Here’s the VSX link for coordinates and other information: TCP J18265456-2719122. Thank you! - Elizabeth Waagen, AAVSO HQ