Judd 79a is a pattern for a new Seated Liberty Half Dollar. With some modifications, the obverse design appeared on regular issue Half Dollars in 1839. The reverse design is similar to that of the Gobrecht Dollars, and was never adopted for regular coinage.
According to the Judd reference, both Originals and Restrikes exist of this type. Originals are on heavy-weight (200-206 grains) planchets; Restrikes are supposedly on lighter-weight planchets. However, the research site at www.uspatterns.com notes that no J-79a's are known on lightweight planchets. We do know that at least one example was restruck at the Mint in 1843 expressly for Matthew Stickney based on contemporary documentation. Researcher Saul Teichman suggests that any lightweight planchets should have extensive central die cracking as on the Judd 73's.
An estimated 10-12 Judd-79a's exist today.