Thanks all.
I wish the comet wasnt so far north, my mount is permanently set up and aligned in the back yard and cant see further north than about zero degrees in Dec.
Will have to save up for coating the corrector plate, I wonder if the reflection is coming off the front or rear, or both surfaces. The corrector is made of ordinary plate glass as if i look through it edgewise, its dark green, so I guess a few % of light is lost there too.
Scott