Aperture is how big the field stop hole is. It is usually located at the focal point of the EP. This is where you are going to put the crosshairs if you plan on seeing them in focus! This also means that you will have to make the appropiate fittings so that you will be able to focus on the crosshairs and then focus all of that on the image from the objective. If all of that is buried in the focuser because the field stop is down in there then you are getting into a lot of different problems. Since the field stop is the largest thing that you will be able to see in the EP then anything outside of that ring will basically be invisible (providing that you "black out" any light from the LED. Clamping is better the word that I used to describe the locating of the filamants and if you use a lexan or other clear plastic, then you will be able to route the light to all 4 of the ends of the filaments. Think of what you need to do and it all becomes obvious to the person that has done it many times. Most EP's don't get this treatment because they need to be fixed in the focuser in order to be able to do all of the things that need to be done - the field stop is down the tube a ways. Good Luck!

• Re: Illuminated Crosshairs - Glen_Warchol/">Glen Warchol - September 22, 1998 - 22:46 UTC