You ask, is this also a costume pattern? Sorry, NO.
So, if not, what is Vogue trying to sell? This pattern came out in the 1970's so they must have been aware of the 1967-1970 running TV show and Sister Bertrille. Right?
Note: Okay, research has revealed that Sally Field's costume looked nothing like this, but still...
Daughters of Charity cornette
The envelope illustration is a much better representation of the dress. However, it still gives off a futuristic very Star Trek or Star Wars circa 1977 (the original) vibe. You know, "Obi-Wan Kenobi, you're my only hope ..." But then, the Star Wars costumes in that first movie were also very medieval influenced.
It was probably good news for the modest brides that it was evidently designed for because there is no hint of skin visible, not even that tempting and highly scandalous wrist area!