Helicon (15 miles) is out in the Mare Imbrium, the Sea of Rains. It has a sharp rim and is a little over 1 mile deep. It is well placed for observation 2 days after first quarter. The floor appears to be flat and featureless in my 6 inch refractor. It makes and attractive pair with Le Verrier, just 17 miles to the east.
Le Verrier (12 miles) is a little smaller than its western neighbor, but it is a little deeper. The flat floor reveals no detail in my 6 inch refractor.