Netwolf, Mercury is not a crescent at this stage (the picture was generated with CdC, for Sept. 25th, 19:00)
Also, it is at the far side of its orbit, so I do not think you can see the disk with 10x50 binoculars (currently it is 5" in diameter). What you saw was most likely due to a not-so-good optics. Check with some bright star....
Bojan
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