Is this yarn the same as what’s being called for in this Knitty pattern?
Looks like it to me! 
Looks like it to me!
The yellow top calls for Sonata, and the white top says it’s from the Endless Summer Sonata patterns, which seem to be a collection of patterns for that specific yarn, which is apparently DK in size.
That’s the same as the Soleil, I ordered some for a Soleil I’m knitting for my sister