I don't think the man on the moon will even know he's there.Brandishing?
I'd check with NASA first, just to be on the safe side.
If he's practicing with a 10mm then I'd say better to check the weapon twice. If you have a ND you may berry well knock the moon out of its orbit slightly. I'd be careful.
Unless it's low to the horizon you'd be aiming pretty high. I guess if it's just static practice isolating the actual trigger press maybe it's good. I prefer staring at a mirror and drawing from holster after asking if my reflection is 'talking to me?'
I don't think the man on the moon will even know he's there.