10 inch F10 Refractor

Hi All,

The old man is at it again. Did a 1500mile turnaround trip a couple of days ago to pick up these, no longer needed, bits and pieces to a 10" F/10 refractor. The college I got them from has much newer stuff so this became obsolete a few years ago. The OTA weighs about 80lbs. Too much for this guy. I will have to rebuild this 55 year old Navy/Air Force tracking refractor.

Stay tuned

Keith (Scopejunkie)

Attached Image:

Right about now I'd be looking for an optical flat mirror to make a folded refractor...

Hi Rod,

We shall see. Right now I'm debating on if I'm going forward with this project. Even if I make a new scope around the lens it may still be too heavy for this old guy. I may end up having to sell it despite my dream to own such a large refractor. The lens assembly weighs around 35lbs.

Keith (Scopejunkie)

Attached Image:

Test setup. 5" F/9 versus 10" F/10

Attached Image:

Whew! Got the scope up and mounted. I'm gettin' too old for these kinds of antics Anyway, Jupiter was well seen at 240x. Lots of details. The moons were showing disks of differing sizes despite the 5/10 seeing. The color correction is very good. I was again surprised. Jupiter had a faint tight halo that was less than my 5" F/9 refractor. This is not a standard achromat. I'm guessing that the slightly yellow tinted crown element is in fact a lanthanum lens (55 year old lens). A 10" achromat at F/10 should have much more color. I pushed the lens to 420x on Jupiter trying to get the color to be more obvious but to my surprise it was less. My guess was a more precise focus? Saturn revealed all the usual details. The image was seeing limited. Altair revealed above average color correction as well.

250lpi glass ronchi at 3 bands revealed good spherical correction and a clean edge. Seeing was not good enough for critical star testing. The stiff mount didnt help.

The DOB mount in the pic is a massive beast. Heavy, and a lot to move around. Buttery smooth DOB motions? NOT!

Keith (Scopejunkie)

Attached Image:

Lots of rework. Tube is split into three components. Much easier to load up and assemble. DOB mount needs some work. Will use it till I get the Cave mount that came with all the parts back in working condition. Reweighed the lens assembly. It actually only weighs 20lbs. My estimate was quite a bit off. Still tinkering

Keith (Scopejunkie)

Attached Image:

Aligned the focuser and the lens. Reworked the DOB mount. This will do till I can get the GEM up and running. Still hacking...

Keith (Scopejunkie)

Attached Image:

Well... let us see what we can see...

Keith (Scopejunkie)

Attached Image:

That 10" is quite a contraption

Made any progress on making it more friendly to setup?

The scope hurt me bad enough that the I sold the lens. Took me couple of weeks to recover from the weeks of handling the instrument and scope rework. I thought I could deal with it like many of the other monsters I have had in the past but, at 65, the body says no. The optical tube assembly alone was about 60lbs. After weeks of use I realized that it's not something I would enjoy to putting up every night I want to observe. If the deal wasn't so tempting I probably wouldn't have bought it in the first place.

It was a good performer. The planets were well seen. Building a 8" cass currently.

Keith (Scopejunkie)