Ibrahim, Betsy
Today, Betsy and I set up a Dino-Lite to image the spots we found yesterday (alog 90147).
Below are photos including before and after cleaning - according to the names of the files. None of the spots seemed to change after cleaning.
We also cleaned the spot that's in the center (not imaged with dino-lite) but it also did not go away.
Current most likely hypothesis is a coating defect due to circular nature of the spots and the resistance to cleaning.
All of the spot pictures are un-cropped since the dino-lite was jigged to be roughly the same picture size and therefore show the relative spot sizes from one picture to the next. The last picture has a 2mm disc shown for scale (a banana was way too big, thankfully). The attached shows roughly where the 4 spots are. From some estimating on the pictures, spot sizes are roughly:
1: 0.5mm diam, bottom of the optic
2: 0.3mm diam, bottom of the optic
3: 0.6mm diam, centerline, but left a few inches
4: No pictures, almost dead center of optic so riskier to photograph, but much smaller like 0.1-0.2mm diam when visually comapred to the other spots
tagging for photos