<https://stargazerslounge.com/topic/310043-has-anyone-seen-this-effect/#comment-3391196>
<http://schema.org/text>
"Yes when I looked inside the QHY5 after that occasion, the foam was sticking out and covering part of the sensor.  I pushed it back and it seems to have been OK since.   Obviously as a guide camera I was only doing 1sec exposures and could not understand why I couldn't see the bottom left corner of the screen it was fuzzy.   In much longer exposure and with tracking, I guess you would see some stars between the porousness of the foam.  \n \n\n\n\tIt's worth a look, but if that is the case on your camera, you might have to tip it in different orientations to see whether any foam falls out intermittently as it seems to happen only on some targets.  \n \n\n\n\tCarole \n \n\n\n\t \n \n"
<https://stargazerslounge.com/topic/310043-has-anyone-seen-this-effect/?tab=comments#comment-3390936>