Jim, Yes if you are able to handle the physical size of the scope when ... in Storage, Transportation, Setup and breakdown, it is worth building a large aperature scope. In the 22" size, you will need to built a dobsonian, or build a HUGE mount. I have a large mount coming which would be able to support a scope of that size, but the mount is so heavy that it has to be on a permanent pier, and it's scope will be left at home unless I build a custom trailer for the mount and pier. (It's 175 lbs for the mount alone, not counting the counterweights drives or electronics. The entire setup will probably end up being 500-700 lbs total. Too heavy to be portable) When building a 22" scope, you are gaining additional resolution and light grasp. But remember that the long 11' focal length will limit how wide a field of view you can see. Even with a 32mm super wide field eyepiece, you will have 103 power and somewhere around 1/2 of a degree true field of view. If you are wanting to do deep sky viewing, you may want to go with a shorter focal ratio. Properly figured, a 22" F4 scope will have minimal off axis aberations, will be able to handle high powers easily, but will still give you a wider field of view when hunding DSO's. The additional benefit is that the scope assembly will be much easier to design and construct than the F6. Remember that the physical size of a 22" F6 scope will pretty much dictate that you have a dedicated trailer to transport it, or have a large van or truck just for the scope, and will not have much room left for camping gear or the rest of the family. While a F4 will be small enough that you might be able to fit it behind the back seat of a suburban and still bring the family along and have some space in the back for camping gear. That extra 4' of focal length realy does have an impact on transportation. Just food for thought. John Zeigler www.JohnsTelescopes.com <http://www.JohnsTelescopes.com> www.MirrorKits.com <http://www.MirrorKits.com> -----Original Message----- From: Gibson, Jim [mailto:gibson@dpg.army.mil] Sent: Tuesday, September 30, 2003 5:08 PM To: 'Utah Valley Astronomy Association' Subject: RE: [UVAA] Scope Length John thanks for the reply. I have been toying with the idea of building a 22" f 6. That would make the focal length 11 feet long. I wonder if it's worth it having to climb a 10' latter. I made a 12.5" f 7. It should be about a foot shorter than yours. I am kind of wishing that I had made my f 8 now. Oh well. Jim