Pleiades with strange ring structure

[mxpwr]

Took 3 8 minute subs of pleiades the other day and was wondering why I have some ring structure to the far right (looks like a super nova remnant), that is not visible in other pictures of Pleiades?

Doesnt seem like this is caused by smudge on my optics, but maybe some processing artifact or am I too stupid to google?

[emadmoussa]

Brilliant!

[Stub Mandrel]

Given the rings around the bright stars I think it's a reflection somewhere along your tube/focuser.