- William Optic
This is a wonderful edition to a Zenithstar 73 and essential to astrophotography. Just be aware, that the distance of the sensor to the the front of the flattener is absolutely crucial. Go to the William Optic website and get the technical drawing to set the distance. Get your optical train to have 55mm backfocus, and then use the adjustment on the flattener to make up the difference based on the technical drawing's given value for your scope (its for the Z73 and Z61). I thought I could make this up with focus, so was very frustrated at first. However, the good folks at OPT set me straight and I absolutely love this device!
WO 73 PROBLEM SOLVED
After trying 3 different WO flatteners for the WO 73 the one that works for me was the Flat73A- not a reducer so you get 400 + FL and also able to rotate field like the WO 73R
Matches my Zenithstar 73
Like the build quality. Haven't had first light yet, but I anticipate good performance.