I have just spent some time chasing defects in my images when running a C14-Hyperstar-ZWO ASI 6200MM combination. I found out that the darks had gradients. Although I covered the LED with tape it wasn't thick enough and was red in colour rather than black. I believe this was the source of my issue. I searched forums to see if there is a mechanism to switch the LED off, to discover there is none. I would therefore like to reiterate Bvin's request
Thanks & regards,
Niall