For For planetary : Pentax XW 7 is good for a C11

I would like to buy a good eyepiece for planetary for a good C11.

The Pentax XW 7mm is good for it ?

The 5mm version is too much ?

Thanks

The 7mm XW is a great EP, but 400x might be a bit much for the C11, I am not sure what your viewing conditions are like. The 7mm XL is also a great EP and the cost is a bit less. The 5mm is a wonderful EP in the XW or the XL but then it is 560x and that sure sounds like too much power for a C11.

Jean,
I had a Celestron 9.25" SCT and found for planetary viewing the 7mm Pentax XL was the most used eyepiece in my collection. There were very few nights in MA and in FL where I had to step up to a 10.5 Pentax XL. Contrast was wonderful both eyepieces. As for the 5mm....I wouldn't recommend it. It's just to much power for the scope.

Keep in mind my focal length in the 9.25 was a bit shorter then an 11. I was pushing 335x with the 7mm. If you use the 7mm your scope your looking at 400x. With the 10.5.....266x. But the extra aperture might allow you to push the planets a bit more then my scope. I say go with the 7mm XL, I saw one on astromart for $195 (it's still for sale). Go with a used eyepiece. This way if your not happy with it, you can sell the eyepiece without loosing a lot of money.

Another suggestion would be to try and get yourself to a star party and meet someone with one of those eyepieces. Try it in your scope and see what you think. This is not always an option though.

Clear skies,
Jay