Seems to be a popular choice at the moment.
As luck would have it, it was a lovely night last night so I thought I'd play around with DSLR Focus a bit in piggy back mode to see how close I could get to focused manually adjusting the focus on the camera.
For those who've not heard of it DSLR Focus is designed to assist in prime focus focus
Especially if you have an electronic microfocuser attached. Unfortuantely I'm still having difficulties with my wedge for the LX200 so I piggybacked on my Eq mounted refractor and manually guided with a reticle.
Detail
Canon 300D with hack using mirror lock
200mm FL (not happy with this lense. Gives a lot of flaring)
f/5.6
ISO 1600 3X 240 Sec
Piggyback on HD-102EQ manually guided in RA only
Dark subtracted in PS
Stacked in Reg3, not adjustments
Levels, curves, contrast in PS
Conclusion: I need a better lens
otherwise with practice I feel it would be of great use even doing piggyback work