As promised yesterday, I'm going to tell you a little about my experience with the 127mm homebrew refractor. The first item I went to look at was a semi-bright star. Not certain which one, I think it was one of the belt stars in Orion. As I recall, it was a yellowish star. I noticed right away that if the star was focused in the center of the eyepiece, as it drifted, it got progressively blurrier as it went off center.
Then I went after M42, as its easy to find and I was in the neighborhood anyway. It was quite bright, compared to the 70mm and 114mm scopes I have. Of course, M42 is much brighter in the 8 inch Dob, which is to be expected. A quick peek at Sirius showed a blue star, pinpoint and bright when focused. From there, I attempted M51, Canes Venatici, but couldnt locate it. After spending some time searching, I proceeded to Saturn which was higher in the sky. There was thin cloud cover, more like a haze, the moon, low on the horizon illuminated the haze, and could be why I was unable to locate M51.
The home made focuser has no side to side slop that I could see. However, it was not square with the tube, which I corrected today. This is probably the cause of the focusing issue I was seeing. I was not able to focus on Saturn as well as I have experienced with the 70mm refractor, but at the time I attributed it to the hazy sky.
Knowing that the telescope needed some more work and some fine tuning, I brought it back in after looking at Saturn. Today, I re-seated the objective and squared up the focuser as best I could. I used a laser flashlight and found the laser was off to one side of the objective. I rotated the laser to make sure it was aiming straight, which it wasnt, but as I rotated it in the eyepiece holder, I saw the dot on the lens, rotate in a circle. I then adjusted the focuser so that the circle was centered approximately equal from the outer rim of the objective as I rotated it around inside the holder. (the laser flashlight fit fairly well in the 1 1/4 inch focuser with very little slop). I believe I have the focuser much closer to being true.
Now we need clear skies again to test the scope again.