Now the next thing we're going to go over for your telescope is eyepieces. Just as crucial as your optical tube or your mount. You can see I've got quite a variety of eyepieces to choose from, and on the industry standard for eyepieces is what they call inch and a quarter. That means that the barrel size here is an inch and a quarter barrel size. Now the eyepieces that I have here will typically go into just about every telescope I have here. The difference is they will offer a different magnification in each eyepiece, and the field of view is different on each eyepiece. Then some of the major differences, obviously, between a thirty dollar eyepiece--which you might consider--or a three hundred dollar eyepiece. A thing to consider also is eye relief when using an eyepiece. If you're an eyeglass wearer, you want to get at least twelve to fifteen millimeters of eye relief, so you got a little separation between your glass and the lens. An eyepiece like this has generous eye relief that allows you to adjust it to find that sweet spot just a little bit, where as an eyepiece like this right here is just fixed. Along with selecting the eyepiece, it's appropriate and important to know about your diagonal as well. The diagonal goes onto the back of the telescope and is crucial for allowing you to bring the eyepiece to focus. Most telescopes--the majority of them--will come outfitted with an inch and a quarter diagonal designed to accept inch and a quarter eyepieces. As I put the different eyepieces into different focal lengths, they give me different magnification, and I can focus quite simply at the telescope. If you've got a longer focal length telescope, like the Schmidt-Cassegrain here, and you're into deep sky objects and you want to bring those dim fuzzies in a little bit, a great accessory is to upgrade from the inch and a quarter diagonal to this big two inch guy right here. Now you can see, as opposed to allowing an inch and a quarter of light into the diagonal, now I'm going to open up that circumference and allow two inches of light to enter my eye. And that can go in quite simply, and now that would allow me to accommodate what you see behind me here with these big two inch eyepieces here. Now, very impressive hand grenades they look like here, and you wonder what the difference in between such beasts. Well, a big eyepiece like this guy right here--the two inch--are typically designed for a low power and a wide field of view, and when you've got a premium two inch eyepiece like this, it's really like looking out of the space shuttle port window. You could look down into this eyepiece and you could look to the left and to the right and back and forth and it really is like looking out of a window into space. Also with an improved eyepiece, your views stay sharp from edge to edge. Many times you'll look into an eyepiece and those stars will look nice and sharp in the center, but as they get off to the edges a little bit, they start to fade off and they don't quite have the same brightness. Now, I could put a two inch eyepiece into my telescope and boom... those views are much more amazing, much brighter, much incredible, and just a two inch eyepiece is really something exciting you should have in your collection. For higher power, for planetary use and on the moon, we still like an inch and a quarter eyepiece, and with a simple adapter right here, my inch and a quarter adapter, I can put that right into the two inch diagonal and it allows me to use inch and a quarter eyepieces without having to swap out my diagonal. Now there are a lot of eyepieces to choose from, and you want to get one appropriate for your telescope. Get the best eyepiece you can, but obviously you don't need a six hundred dollar eyepiece with a two hundred dollar telescope.
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