That's a great Cat's paw Colin! With that wide field, if you had panned up and right a bit you would have captured the Lobster in the same frame.
As to the blue, my only pic of it that's wide-ish is from my 6" F5 I took back in 2015. There's a hint of blue in mine but knowing me I probably thought it was a gradient and processed it out.
So I'm not much help really.