Fast forward 30+ years. There was a cheapo 6" F5 objective on ebay that was badly scratched during cleaning for cheap. I decided to follow up on the short refractor just for fun. I figured if I liked it I would get a better objective some day. I made a non-adjustable cell and tailpiece, and had a short section of tube. To keep things simple I used a Kineoptics helical crayford focuser and a Lumicon 2" diagonal, because I could easily remove one of the the tubes from it and replace it with the focuser.. I read over and over how that short of a refractor would have a lot of CA, so I got the Baader semi-APO filter that is permanently mounted between the objective and the diagonal. Over the years there have been lots of articles both in S&T and online about very short focus 6" refractors - so I kept hearing about it with different points of view. Some refractor people really don't like short focus because of the CA. Others (usually reflector people like me) don't seem to mind at all.
The picture of the original construction is below. I originally left it unpainted and basically unfinished. Due to the cleaning scratches the resulting views were really soft and low contrast, but I really didn't mind the CA using the Baader filter. So I felt I proved out the design. I started waiting for a reasonable objective to come along.
I looked at the new Jaegers site in 2008 that listed the 6" F5 lens set, but they wanted $1750 for the glass. No real description or qualifications so I wouldn't take that chance. The scope sat until Istar came along. They listed a 6"F5. I waited while someone else here (Mr. Bill) at CN took a chance. While he had some glitches, things worked out well for him so I decided to give Istar a try. The price certainly was right.
I received the lens last week. The workmanship is very good with nice polish and coating on the lens. The push/pull cell is well done. I had to make a tube end that mated to the cell and adjust the tube length to compensate for the cell. My 1936 9" lathe had just barely enough torque to turn the parts. Almost every detail was worked out on a drawing before cutting metal. I can post a PDF of the drawing if anyone is interested. The dew shield is a stainless steel cannister with a cool rubber cap that seals off the lens from the outside. Handles are from an aluminum pot. There are 2 internal baffles. Without an eyepiece the scope weighs 17 pounds.
The Kineoptics focuser has 1.25 inches of travel. I use Vixen LVW eyepieces plus a 31mm Baader Hyperion. There's about a 3/4" difference in focal plane between the Vixen and Baader eyepieces so there's no problem there. The diagonal makes the view upright but leaves it reversed left to right. For this type of scope, the 2" diagonal and 2" focuser does chop off part of the useful light cone. If I feel I need to correct that the tailpiece is large enough so I could attach a larger mirror diagonal (but I'd have to scratch build it).
The skies have not been amenable for star testing lately. The terrestrial views are quite good but I need to get some star work in. I'll report on that when the clouds clear.
I'll put up some photos of the new construction in subsequent posts.