More to explore:
Sydney Opera House analogy cornette wimple
The vampire and the nun by Baldovino Barani for Oyster mag Jun/Jul 2009 via cltreanor
"The Sydney Opera House TotallyLooksLike.... the Flying Nun's hat." by jlgrand62
Headwear: June 1809 Ackerman's Repository. 1. Wimple or hood, 2. Silver net dress cap 3. yellow silk walking bonnet 4. promenade headdress, and 5. dress hat of cerulean blue.
Robert Campin 1425-8 , The Merode Alterpiece, detail -wimple and 2 veils
Audrey in Sydney Opera House hat
Barbette - linen cloth that passes under the chin to the top of the head. It developed from the wimple. Could be worn over a crespine hairnet or a veil. 13th century fullness.
sydney4 by Flickr user Orla Cahill Millinery
OB wears opera house hat, via Flickr.
Also nun party.