Dave, I used a curved spider on my 4.25" f/5 "Woodshop" scope. I didn't get quite enough curve in it, however, and bright objects have short, curved "horns", that dwindle-off into invisibility. This scope demonstrates a mid-point between straight spider vanes, with reinforced diffraction, and curved vanes, bent sharply enough to distribute diffraction effectively. I have an optical window for this scope, and have planned to retrofit it for years now (it's a long "to-do" list) but I'll keep it in it's current configuration and bring it to this year's Binopalooza if anyone wants to inspect it. Keeping conventional vanes as thin as possible helps reduce diffraction. Many ATMs have used thin wire as spider material, and claim huge reductions in diffraction spikes. C. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - forms, calculators, tips, more http://taxes.yahoo.com/