Had a try for the new possible nova in Centaurus (circa mid mag 9s) between cloud tonight using a Star Analyser grating and 400D at 200mm with 4-min exposures. No luck I'm afraid, probably about a magnitude dimmer than my limit.
The small-sized grating pulls the aperture right down and there's no way I can do substantially longer exposures.
Did get an image of the possible nova though, attached.
Cheers -