18UC--I see you are buying an 18 inch Teeter; you already own an 18UC, right? Is there a reason you are switching to an 18 inch Teeter?
The short answer is I dont have the 18UC anymore, just the CN handle. I dont think I can change that without re-registering.
Well this is the long story....
In April of 2008 I was at the regional star party with my 6.5" Mak-Newt. That was a great scope, I was able to split Porrima at 330x and have a wide field 2+ degree Milky Way. But...
I was surrounded by big dobs: 15", 18", 20", and 25". For several years I took my 12.5" Discovery, I was the smallest of the big dobs, or largest of the small. The 12.5 never had trouble keeping up with the big boys. But that year I took a smaller scope and the lesson of aperture really hit me.
I went home and looked at big scopes. All the Obsession owners I knew were happy. I liked the classic truss scopes. The 18" UC was new and different. It looked nice on the internet.
The first night I set it up I was unable to collimate it. Just using a laser, I was unable to get the return beam to even hit the secondary. I called them and was told to send the truss back (at my expense) Turns out one truss pole was too long. The trusses are all connected, I wasnt about to take it apart and fool with it.
I got that fixed and used the scope over the next two years. I had ServoCat installed for tracking. The views were great but there were problems with the scope: vibration, dust, stray light, collimation shift, altitude cable came off every time the bearing was folded over. The worst was the mirror sling, it kept coming out of the metal post. The sling was too short and not even wrapped around the post once, I think its supposed to wrap around two or three times.
The best thing about the scope was the OMI mirror, a fantastic, if heavy optic. Ive already been excoriated on this forum for expressing my displeasure with Obsession, but when you spend that much, when you work every weekend and holiday to afford something nice, you want it to work.
Not be perfect, just work good the first time.
An observing buddy has an 18" Obsession from 2001. It works great. I really like that scope. Maybe if I had bought the truss...
I sold the structure and kept the mirror. I contacted Rob Teeter. His stuff looked good and he will use your parts. If worse came to worst, he's at NEAF every year. In late 2010 I picked up my new Teeter 18". The scope fit (barely) in my compact car. It was easy to setup and use. I took it to the week long star party and had a ball. I think I just looked at Jupiter for 3 nights straight.
As good as the scope was, I still needed a stepstool to view as the eyepiece was 72" at zenith. I had trouble with arthritis and stepping on and off the stool for several hours was exausting.
In December of 2011 I ordered a mirror from Gordon Waite. I didnt want a specific focal length, just 65" or less at zenith. The mirror was ready in September. I took the old structure up. I picked it up earlier this month. Rob made some changes and improvements.
Last weekend I took it out to a semi-rural site. I just wanted to try the scope on familliar sights and see how things work. Well, it works, and works well. I can sit and observe, motion in alt has a much smaller arc than before. I saw spiral arms in M33 and 51, the separate NGC's within M33, old friends 2403 and 2903, lumps in M82, the two close doubles SW of M81 were resolved, and I saw Thor's Helmet for the first time. I live in the city so I cant see these often.
My problem with this scope is the fast focal ratio. With the Paracorr its about f/4. So a 20mm eyepiece gives an exit pupil of 5mm. I need 2mm and below not to see astigmatism from my eye. But I can still use a 4mm eyepiece for really high power and still have 1mm exit pupil, and no floaters. For me, <1mm = floaters, >3mm = astigmatism.
Im looking forward to spending a good night in Coma Berenices and Canes Venatici: NGC 4565, 4244, 4361, 4656.... I havent seen these in so long.