moth i.d. Ohio

[Shellyzoo]

Hi!

I must confess that I am a complete neophyte when it comes to lepidoptera;
until about 30 hours ago, I was an organic gardener that enjoyed attracting
various unnamed birds, moths and butterflies and wasn't too concerned with
identification.
Obviously, something changed, and what changed me was seeing what I think was a
most magnificent moth. I stood transfixed for several minutes until I lost
sight of it.
 This moth ? kept its wings spread when at rest. It was huge, at least 6 inches
across (I am really trying hard not to exaggerate, I want to say 7 or 8) and
was black except for bright yellow dashes outlining its wings. When it flew,
the bottom part of its wings folded up like a butterfly's at rest, and it flew
with just its two front wings.
I live on 5 acres that is surrounded by fields, but with some meadow land.
There are pin oaks and dogwoods, locusts and maples on my property, as well as
about 3 acres of wild shrubroses,blackberry and other introduced or native
shrubs and meadow plants. I just moved here so there aren't any cultivated
flowers yet.
I have spent hours on the net the past two days trying to i.d. this wonderful
creature, clicking on every picture on moths in Ohio, and btterflies, but I
haven't seen anything close.
I know this is not much to go on, but if anyone could at least point me in the
right direction I would be very grateful.
In the meantime, camera in hand, I will go hunting.

Thanks so much; Shelly
shellyzoo at aol.com
Good luck and good gardening
Shelly
zone 5 OH