Jay --
This photo appears on page 30 of the Spring 1984 issue of the SABR publication "The National Pastime", a pictorial issue on Baseball in the Nineteenth Century. There it is identified as "two Brooklyn Stars, ca. 1870, of whom the one on the right is Candy Cummings". The uniforms look almost identical to the ones in your picture, albeit with black pants rather than white, though I don't know how common such elements might have been for clubs with the "Star" name. But that's my best guess. The 2013 book "Base Ball Founders" has a 23-page history of the Star Base Ball Club of Brooklyn, but without any pictures, alas.
