My Pulsar scope is set to NUC whenever it wants and my slightly older ATN OTS has to be manually done. You have to cover the lens of the OTS when you NUC it or you'll ghost in whatever it sees when you hit the button. The Pulsar appears to have a new image without covering the end.
How do the newer scopes NUC w/o covering the lens?
M&P-10+AAC Cyclone - Kel-Tec RFB+Griffin Sportsman Ultra Light 300
Pulsar Apex XQ-50
ATN OTS 336-70mm 60hz Thermal Monocular
ATN OTS 336-30mm 9hz Thermal Monocular
ATN NVM14 NV Monocular