Pete you can't use the barlow as is, but if you remove the lens elements and screw it directly to the ToUcam 1.25" adapter it will work fine.
These two images are of a tree about 1/3 - 1/2 km away from my veranda. The first was taken with the ToUcam 900 and the second with the 840. The 900 has a longer modified adapter which is why it looks slightly greater magnification. I could easily focus on some clouds on the horizon so it will reach infinity in this format. The focus on the trees is not good on these shots as it is blowing a .....proverbial atm, with stars though I have been able to get it nice and sharp.
The DSI should be np at all.
Having said all that....do yourself a favour and get the Tak 60 and required accessories before I do
