114mm Newt, webcam and 2x barlow = magnification ?

Hi all,

I have just managed to get my first ever webcam avi shots using my
mead DS115 (no comments...), a toucam pro and a 2x barlow, no
eyepiece.

As usual the goto failed and I could not get the tracking to work so I
ended up capturing saturn and mars as they 'floated past'. Oh and did
I mention the wind, so it was really a 'wobble past' The results were
rubbish and my son thought mars was a flying pimple! Duh...

Anyway to the the question : As I did not use a lens (ie webcam on a
threaded adapter and slotted into 2x barlow), how do I calculate the
magnification?

Thanks,

Reddog

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