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Williams Optics 2" Diagonal and UO MK-70

Started by astroboy314, 01/09/2003 07:27AM
Posted 01/09/2003 07:27AM Opening Post
I just upgraded my 8" SCT to a 2" diagonal, and purchased the Williams Optics 2" diagonal. I was very happy with it until I received my first 2" eyepiece, the University Optics 40mm MK-70. They are an extremely tight fit. It's so tight that I really have to force the ep in, wiggling and twisting it as I go. Last night in the field I wanted to change eps, and I couldn't get the MK-70 out of the diagonal. I was pulling and twisting very hard, and I still couldn't get it free; efforts this morning give the same result. I am worried that in trying to free the ep I'm going to damage something.

Has anyone ever experienced this with a diagonal and ep? Should I be contacting either company and questioning them about it (I have acess to a digital vernier and could measure the dimensions very accurately)? Are there any possible solutions to this problem? For the first time in my life I got really frustrated while observing.

Thanks for any advice anyone can offer.

Posted 01/09/2003 08:03AM #1
I purchased the WO 2" diagonal over a year ago and it would not fit inside of my Intes mk67 without getting stuck. I also have the UO MK70 but never got a chance to use it in the diagonal.
Posted 01/09/2003 08:04AM #2
While I'm not declaring the following to be SAFE, I (that's *ME* -- not necessarily you or anyone else) would probably try a *brief* dose of heat to the diagonal's eyepiece collar. It might expand enough (relative to the eyepiece barrel) to loosen its grip. I'm thinking maybe about three seconds with a standard cigarette lighter or wooden match under a portion of the collar (don't try and heat the entire circumference; maybe a thumb-sized area about .5-.75 inches below the top/rim of the collar). After three seconds, remove the flame and quickly try to dislodge the eyepiece.

I would try *neither* a hotter flame *nor* a longer-duration heating, as there's tricky stuff involved (i.e. glass, conductivity, differential expansion).

Again, that's what I myself would probably try. I suggest gathering more folks' advice before trying *anything.*

Best wishes and luck.
Posted 01/09/2003 08:35AM #3

I have a 2" WO diagonal. I found that the compression ring was a bit distorted and tight. Sounds like yours may not be seated well in its track. When you do get the ep out, pull the brass compression ring out and bend it open, ever so slightly so that it "springs" into its groove in the diagonal. Anyway, this did it for me, perhaps it will for you.


Randy Roy
Posted 01/09/2003 08:37AM #4

I have the WO 2' diagonal and have been experiencing this problem with the 2" to 1.25" adapter with just one of my 1.25" eyepieces. After some wiggling it comes out. All the other 1.25" eyepiece seem fine. I have not notice this problem with the 2" eyepieces I own. The one eyepiece that I am having the problem with is a Pro-Optic Ultra Wide (same as the Orion Expanse) that has the recess groove in the barrel. So I am thinking the groove is getting caught under the brass ring in the holder. Some of my other 1.25" have this recess groove but again not a problem. One thing I did notice is the edge of recess groove on this Pro-Optic UW is flat while the others are beveled. This is where I developed my theory it's being caught on the brass ring (i.e. a beveled edged recess groove would push the ring out, therefore, releasing the eyepiece without much trouble).

I figure this problem is something I would just have to deal with when using the Pro-Optic UW. As long as it does not get stuck like your MK-70.

One thing I can say is those holders seem to be very precisely cut. Last night while out I dropped my Ultima 12.5mm eyepiece on the concrete that put a small hardly noticeable nic on the outside bottom of the barrel. When I tried to put the eyepiece in the diagonal it would not fit due to this small nic. After filing across this nic a few times it worked perfectly.

Good Luck,