Actually it's a doublet. Or an achromatic doublet achromatic is a description of the lens correction and form achromat (corrected for chromatic apparations) achromats can have one lens or be composed of several lens elements. . There is such a thing as a double meniscus btw it's composed of two meniscus lenses and is therefore called double meniscus. The french meniscus landscape lens a variation of the achromat was composed of two meniscus elements.
But all in all you are right a rr is composed of two achromatic doublets. My mistake
But all in all you are right a rr is composed of two achromatic doublets. My mistake

I will never trust you again. Never. 


