Is it normal to see condensation forming?

Is it normal to see condensation forming on the vacuum chamber window of a probe station?

As it has line-of-sight to the sample stage, the window can radiatively cool below the dew point. Particularly in higher-humidity environments, the external viewport window can develop condensation during low-temperature operation. Excess condensation can make probe placement more difficult and is an indication that the window needs to be cleaned or treated with anti-fog solution. However, if actual frost is beginning to form on the window or lid, the vacuum level in the chamber may be too high, indicating an issue with the vacuum pump or chamber vacuum seals. Contact Lake Shore Service for further guidance.