[Miaplacidus (Brian)]

I just replaced the lens cell on my William Optics Megrez 80mm II SD with the TMB designed Fluorite doublet that fronts the 10th anniversary Zenithstars. The WO web site says that you can upgrade the following scopes: Megrez 80 II SD, ZenithStar 80, ZenithStar 80 Short, Orion Express, Stellarvue Nighthawk 2, Revelation 80, Astronomica 80, Geoptik 80, and all the other ZS80 achromat clones . The lens alone costs US$399, but a package that includes a 2 speed microfocuser and 2" extender as well costs US$429. (You need the extender anyway.)

Anyway, I was a bit nervous to fiddle around with my scope, but it was actually dead easy. Here’s what you do.

1. Fully extend the dew shield and remove the silver retaining ring that is about 1 cm inside the front end of the dew shield.
2. Fully retract the dew shield (it retracts further now) and expose the lens cell.
3. Rotate the lens cell anticlockwise and completely unscrew it.
4. Carefully screw on the new lens cell.
5. Peel the adhesive felt strips provided and carefully attach them around the outside of the lens cell.
6. Fully extend the dew shield and replace the silver retaining ring.

I took some photos but I won’t post them unless people are interested. (I’m not sure I know how to post photos in the forums.) The scope is slightly longer, but it still fits in the backpack that the Megrez came with. You have to lose an eyepiece spot to the extender, though. The scope was previously an F6.25, now it is F6.9.

So that's the “How to” for anyone who might be interested. Don't be put off thinking it might be hard. (The “Was it worth it?” I’ll post later.)

Cheers,

Brian.