Jake
Yes, it is a Promethea moth and from the coloration it is a male. The male has that dark brown color while the female is more reddish brown with half moon spots on each wing.
These are found east of the Rockies near deciduous forests, so being near a cabin makes sense.
There is one generation per year there in northern Indiana. The larvae feed on leaves of apple, ash, basswood, birch, cherry, lilac, maple, sassafras, sipcebush, sweetgum, tulip-tree, and other trees.
The adults do not feed.
Looks like you are pinning and spreading it. If it is not already dry you could bring the bottom wings up just a little for the best looking specimen. :-)
Thanks for sending in the great photo.
Got my first entomology degree from Purdue! GO Boilers!!
