How to pronounce Erath?

originally, according to my husband, the german name of erath was pronounced ( air rath ) but his family has always insisted on pronouncing their name (Eeeee rath) that's with a long E.

last name

german

Male

my husband has more info and his hobby is linguistics so he is the one to communicate with. we are at a geneology library and he is in another room doing research. please contact him at our website for more information.
thank-you!