No, I’m unsure. It is something specific to the driver as the “ASCOM Environment Sim” does not exhibit these issues. NaN is an acronym for “Not a Number”, so it seems like we are either getting junk for those values or (more likely) we are trying to do trend match with illegal values. The other values use the same exact trend math so something is different about those three. If you can include logs, we can see if any errors are expressed for those values.