A cloudy night on Mount St Helens
However, simply averaging all of the volcanocam images from sunset to sunrise from last night reveals two bright spots on the images - that correspond to the two anomalous glows we have been seeing for some time now (see picture below). Further adding weight to the idea that these anomalies are caused by defective pixels in the Volcanocam camera.
I originally discounted the idea of defective pixels being the cause, due to the fact that the how spot appeared intermittently and varied in size and brightness over the course of the night and from night-to-night. However I think there is a possible explanation for this in the way the images are generated.
The Volcanocan camera is a Sanyo, Model #VCC-4594 Color CCD camera and the output is an analogue NTSC video signal - not a direct digital image from the CCD. The signal is fed to a computer where it is re-digitised and resized before being transmitted to the Volcanocam webserver. I suspect that it is the processing of the digital data to analogue video, then back to digital in the computer (and any other processing/resizing) that adds the variability to the hot pixels in the final images.
Averaging the images over the whole night, like I have done below, would help overcome any variability and we see the hotpsots for what they are - defective pixels. Of course, there's still the problem that the second hot pixel that appeared recently, did not appear on many weeks worth of images at all.
I'll go back over the archives (and produce average images like the one below) to see what happens over a longer time frame...