suffered from RBI

With help from Dave, we determined that my NGC 4388 imagery suffers from RBI. Or Residual Bulk Image. A visual "memory" issue. He shared a link to an article.

This is still fascinating to me as it is not unlike biological processes. It is not unlike the flashbulb effect. You know, when you have a portrait or picture taken and the flash goes off and you see weird coloured dots for a while. Your retina needs some time to recover from the intense bright point source of light. So to a CCD chip will be affected by a previous image with bright objects.

Dave looked at the image shot immediately prior to mine. The user was aimed at BGO-294-MKN421 (aka quasar MKN 421) for 150 seconds. In the field were two bright stars (actually triple star 51 UMa with A at mag 6.0 and C to the east at mag 7.4). Together, over the long exposure, they "blew out" the sensor.

Uh huh.

So, I can stand down. No new fragmented comet discovery...