What does designation VY, NML, UU in star names stand for? I've read the a IAU page on the subject but i am no closer to understanding how this works. Also did search the already asked question, but didn't see anything on the subject.

What does bolded item in the names below stand for? How do they choose them?


VY Canis Majoris
NML Cygni
UY Scuti
VY Canis Majoris and UY Scuti are variable star designations. The first discovered variable star in a constellation is called R, the second, S, and then unto Z. After Z comes RR and so on. For a full description see this wikipedia page. NML Cygni is also a variable star, but its variable star designation is V1489 Cygni. The letters NML come from its discoverers: Neugebauer, Martz, and Leighton.