Just thought I would show you how I Barlow a Barlow in an ED80.
I have no need of extension tubes due to the ED100 long Crayford focuser
ED80, ED100 Crayford Focuser, 2" GS 2x Barlow, 1.25" AOS long tube 2x Barlow, TouCam.
All up, it makes a Veeeerrryyy long scope! and the images are great!!