When you next manage to focus on the Moon, remove the Neximage and place an eyepiece into the focuser and slowly insert it until the image comes to focus WITHOUT adjusting the focus knob.
Clamp the eyepiece. Your eyepiece and Neximage are now par focal. Either mark the barrel of the eyepiece to indicate how far you had to insert it into the focuser, or use a
“Parfocal Ring” to clamp on the eyepiece, thus registering the parfocal distance.
Then, all you do is insert the parfocal eyepiece, focus on a star, remove the eyepiece and insert your Neximage and touch up the focus on the notebook display.
Cheers
Dennis