does anyone know how to trill from B-flat to c-sharp on the oboe?
i'm referring to the middle register.
all the fingering charts i've looked don't seem to include this interval.

thanks in advance!

It might be a little awkward but you could play the Bb with your 1st and 2nd fingers on your left hand and first finger on your right hand. Then for the C# raise your 1st finger of your right hand and 2nd finger of your left hand while using your 3rd finger(ring finger) of your left hand to push down on the trill key just above your G# key.

That's my best suggestion.

I think you can play C# with out any fingers on the oboe, but that would still be a 3 fingered trill.....

YOu can finger c charp by using the first finger on your right hand. Then all you have to do is move the two fingers on your left hand.