Heritage Auctions of Dallas, Texas, is auctioning a brass dial signed by "Patrick Hepburn, Marlborough, Maryland, 1720"..  The dial face has a rich green patina with rough but accurate engraving of Roman numeral hours, delineated with half, quarter and eighth hour marks. The dial has an eight point compass rose with lettered points.  Latitude is engraved as "LATT 39".The wide, but broken gnomon has a corresponding noon gap engraved in the dial plate.  In the dial corners where there are mounting holes, they are surrounded by floral rosettes.

According to research by Heritage Auctions, "If indeed executed in Marlborough, Maryland in 1720, this instrument represents one of the earliest surviving American scientific instruments of any kind-predating the work of Chandlee and other known American makers by more than half a century. The engraving of the local latitude, combined with Hepburn's documented presence in Prince George's County at the time, strongly supports its colonial manufacture". Proxy bidding ends 24 Apr 2026.  Starting bid is stated as 1500 USD.

https://historical.ha.com/itm/antiques/antiquities/american-made-brass-sundial-signed-by-patrick-hepburn-marlborough-maryland-1720/a/6327-43219.s?ic4=GalleryView-Thumbnail-071515

Additional Location Info:
Heritage Auctions - Dallas
2801 W. Airport Freeway
Dallas, TX 75261