I figured it was about time i worked on my converted B&L BVer i use in my F5 frac, since i've known it was more than a bit out of whack for some time. This is the 3" nose unit which was the stimulus driving my design for the big frac, but i have been using it's little brother 2" nose unit most of the time just because it is well aligned, something i got lucky with a while back with some help from Glenn LeDrew.
Well, i guess i didn't know how lucky because this baby has been a nightmare to collimate. After doing the laser-beam-merging adjustments what seems like a hundred times, i still could not get good results in the scope. Each iteration of the L/R mirror adjustments required disassembly, adjust, reassembly.
Even when the laser looked great at the input lens of the unit, putting it in the scope showed L/R misalignment and/or beam off-centered in the scope objective.
Finally I had enough, and went ahead and did the unthinkable, converted it to "externally adjustable".
Biggest issue was figuring out the exact location & angle of the holes to be drilled in the lower housing, some careful measuring & marking paid off there.
Exactly perfect collimation & beam centering on the scopes objective mask is now a piece of cake. 6 tiny squares of black electrical tape and the "modification" is all but invisible.
A brief look at M42 before the clouds rolled in tonight showed me what i'd been missing with this baby. Awesome. Can't wait for a good clear night, the moon,, the planets, etc