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OPPS! I made an error in the last post regarding 'lowest useable power', it should actuall have been -LONGEST FOCAL LENGTH EYEPIECE FOR A REFLECTOR.
The reason being that you will begin to see the shadow of the secondary mirror in the image, particularly in bright situations like the moon during daylight. This shadow gets worse the longer the focal lenght eyepiece you use.
Some people push this limit to 7X the focal ratio of the scope. It is possible, I've done it, but much more suseptble to shadowing in bright conditions as I've mentioned. I've had a 40mm TMB Paragon eyepiece (brilliant eyepiece) in my f/4.5 17.5" dob. The shadow was there in a dark sky, but careful focusing and head positioning managed to control it. Too hard though. I wouldn't go over the 7X rule, with 6X safer.
There is one more thing regarding eyepieces, those that come with the vast majority of 114 scopes are not the best of quality, especially the short focal length ones. You end up parking your cornea on the eye lens (the lens closest to your eye in the eyepiece, the 'field lens' is the one furthest away), and the field of view is usually narrow.
This makes observing difficult and uncomfortable, the objects drifts through the field quickly and is difficult to obtain.
The good thing about them is that you learn very quickly how to handle the scope really well, just how much 'tweeking' is needed to move it, and improves your 'centering' skills in the process. A challenge though. A skill I picked up after using my 50mm Tasco refractor for 10 years.
A tip when useing high powers if your scope is not motorised:
Center it and see which is the direction of the drift. Then, move the target to the opposite edge of view just out of the field of view, and allow it to drift through. This way you don't introduce as much vibration into the scope, allowing for a much more stable image.
Mental.
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