Rudolf Minkowski.
Its not likely to be the mathematician, Hermann. Nor the physiologist Oskar. There's only one Minkowski who was an observational astronomer.
The paper describing M1-92 was https://iopscience.iop.org/article/10.1086/125855
The 2006 paper on Minkowski's object (Croft et al) cites Minkowski, R. 1958, PASP, 70, 143