MyCn stands for Margaret Walton Mayall (My) and Annie Jump Cannon (Cn), their 39-object catalogue was published in 1940 as New Peculiar Spectra in the Harvard College Observatory Bulletin, no. 913; Mayall has a later 139-object catalogue to her name, designated My: New Peculiar Spectra, Harvard College Observatory Bulletin, no. 920.
ui.adsabs.harvard.edu
Corradi, Romano L. M.; Schwarz, Hugo E. (1993). "Bipolar nebulae and binary stars : the family of crabs He 2-104, BI Crucis and MyCn 18". Astronomy and Astrophysics. 268: 714. Bibcode:1993A&A...268..714C.
