Considering an Obsession 12.5"

Hello Obsession users.

My name is Todd Miller and I live in Billings, MT. I've owned an
Orion 8" XTi with the computer object locator since they first came
out. In fact I order one several months before Orion even had them in
stock. That must be 3 or 4 years ago. My family considered this a
starter scope as an introduction to astronomy. Since then I've
modified my 8" to the extent I was able, acquired a box of eyepieces,
binoculars, an astronomy library and a PST for solar viewing. Off
topic but the PST is used every day the sun is not obscured by clouds,
even if it's only 10 minutes at lunch. We've looked through some
large scopes and are now considering more aperture for ourselves.
Essentially we want grab and go, but I don't see the value in moving
from 8 to 10 inches. As with most of my other toys, I believe once
beyond the beginner stage, premium equipment is almost always worth
the price. On a short list of the scopes we are considering is an
Obsession 12.5" with Argo Navis. Off the top of my head, I'd say I
would upgrade to the Feathertouch focuser, order the light shroud, and
the telrad, and maybe the Barlow-laser for collimation.

Viewing habits
Currently we view every opportunity possible. I travel +100 days
year, but when I'm home view every opportunity possible. Three
fourths of our viewing is from home, the other 25% when we are out
camping. Home location is a couple miles west of town and I have
moderately dark skies to the South, West and North. Camping is almost
always at dark sky sites. At home, I often have to move my scope
around to avoid trees, and the occasional neighbor who has forgotten
to turn off their lights. Most of my neighbors have looked through my
scope and are good about turning lights out on clear nights.

I wear bifocals and have some astigmatism issues. Generally I wear my
glasses, but often slip them off at the eyepiece.

Existing eyepieces:
GS 30 MM 2" eyepiece - this has noticeable seagulls at edge in my 8"
so I expect I wouldn't use it very often in a premium scope. In fact,
I rarely use it now.
25 MM Sirius plossl - used often in the 8" dob.
15 mm Ultrascopic plossl - used a lot at one time, rarely since I've
acquired radians.
10 MM Telvue Radian - Used often in the dob, and the only eyepiece
used in the PST.
8 MM Orion Superwide Lanthanum - Used often
6 MM Telvue Radian - Used when seeing permits - Only had it for 3
months, and MT has been very cloudy last 3 months.
Also spend a lot of time looking at skies in my Pentax 10x50
binoculars.
Filters: Orion UHC filter, a lumincon O-III, and Orion polarizing
filter for moon.

Observing habits -
At home, mostly planets, open clusters, bright nebulas, brighter
galaxies. Lately, I've started to really enjoy double stars.
Dark skies sights when camping - concentrate on galaxies and
globulars. Great views at dark skies are just not enjoyable from home.

After this long introduction, I have a number of questions. I've
requested Obsession's CD and many of these questions may be answered
when this arrives, but I'm going to ask them here anyway as many
astronomers are patient and responsive to those seeking first hand
information.

Here go the questions? All are in reference to the 12.5' scope.
1. How much does the fully assembled scope weigh and can it be moved
short distances in one piece? My wife can move the 8" by herself for
short distance. It weighs only 42 pounds.

2. Are cooling fans standard and what is cool down time? I often
observe in winter. At present I keep my 8" in unheated garage, but
that still means moving the scope from a 50 degree environment to one
of 0-20 degrees. Below zero is quick look glances in the binoculars.

3. How does the Argo Navis computer handle the cold? Can it spend
2-3 hours outside in 10 degree F weather?

4. Can I just leave the scope fully assemble all the time in my
garage? That would be my plan. I'd break it down for those camping
trips.

5. Long term - where are the holes in my eyepiece collection? Top of
my head, I'm thinking a premium wide-field eyepiece, or even a longer
focal length (30-35mm) plossl may well be desirable.

6. What do you use for collimation? I currently rely on Orion's
cheshire eyepiece with cross hairs. Focuser slop on the Chinese dob's
really exclude the use of lasers for collimation.

7. Are you happy with the curved secondary spiders? These have
intrigued me for quite some time. Is adjustment of the secondary
mirror tool free?

8. Will I need a dew heater for the secondary? The secondary on my
8" metal tube has only fogged over on us one time.

9. Is dew or frost on the primary an issue with the open truss
design? My primary has never frosted or dewed over, even when the
metal tube is ice cold. On the other hand, I lack fans and notice
tube currents often as the temperature drops through the evening.
Some nights they never go away.

Thanks for any replies on list or off list to my e-mail address. I'm
looking forward to a larger scope and the 12.5" Obsession seems to
meet my price/performance/size/mobility criteria.

Todd Miller
Billings MT, where's snowing and cold at the moment.