I watched the series of StarTrek TNG that contains a Constellation class crusier. And I keep thinking of what if there was a prototype version in the TOS era. So I came up with this basic design...
The USS VALKYRIE NCC-2590
was in a refit state but in Starfleet data base of starships there wasn't a ship before it's creation or before it and here it is as I imagine it would be. Remember this is only a Prototype
of the Constellation Class crusier.
Design and Photoshopped (c) SR71ALPHA