20 inch setup

This page contains archived images and descriptions of my former 20" Obsession reflector. I sold this telescope set-up to Kent Patterson who took delivery on December 24, 2002. Kent got a great deal and I got the much needed funds to help cover the cost of a new 25" Obsession. I had (and enjoyed) this scope for 3 and 1/2 years and had no problem transporting to different viewing sites, from northern Arizona (Flagstaff) to southern Arizona (Chiricahua National Monument), and a dozen or so places in between. I even used it in midtown Tucson, but dark sites are where this telescope is at its best.

This telescope has a great Galaxy Optics PS2 primary which delivered spectacular images when seeing would allow. Saturn and Jupiter at 1,200x, with the cloud eddy detail almost as good as the Hubble images. The Eskimo Nebula at 1,700x - a ridiculously high magnification, but the detail was spectacular. Having the equatorial tracking platform really helps in being able to resolve finer detail because the scope is not being touched to keep the object centered in the eyepiece.

I chose a couple of upgrades to Dave Kriege's basic package: 1) Galaxy optics rather than the standard Nova optics (on the recommendations of several Obsession owners), 2) JMI DX-1 focuser with fine focus (after having used one at a star party), 3) light shroud (this really shouldn't even be optional), and 4) digital setting circles (I reasoned it was better to have Dave install these because he designed/built the telescope and knows the best place to put such gadgets). I didn't go with the JMI NGC Max computer because I knew I would also be getting an equatorial tracking platform. This platform is reset after an hour and the NGC Max would have to go through the star alignment procedure after each reset. The Sky Commander computer has a "table reset" feature which means realignment isn't needed.

The telescope "breaks down" into 3 subassemblies: 1) the mirror/rocker box, 2) the truss tubes, and 3) the secondary cage. The box is the heaviest component and weighs about 100 lbs. Fortunately, there are wheeled handles that attach to the sides of the box which reduce the effective weight to about 40 pounds. This is very easy to move around (including up and down the loading ramps).


Here's the scope (minus the light shroud) with the wheels/handles still attached.	Here's a view of the primary mirror looking down from the secondary mirror.

Here's a close-up view of the focuser and where I usually hang the computer.	Here's a close-up view of the spotting scope, an 80mm Lumicon refractor.

These are the aluminum ramps (8 ft extended) that are used to get the scope in and out of the vehicle. The ramps are lightweight and easy to use. The ramps are also used to mount the scope onto the equatorial platform. (follow this link)	This is an example of how portable the telescope really is - set-up at Long Lake, about 50 miles south of Flagstaff, AZ. (The blue tarp in the foreground was used to protect the scope from the elements.)

Do you think you might want a larger aperture telescope? Here are some things you should first consider:

Cons:
This is a big telescope and requires the use of a ladder. If you are not comfortable climbing, leaning and sitting on ladders then a big telescope is not for you.

This is not a telescope for impromptu, "I only want to view for 15 minutes" viewing sessions. There is set-up time, thermal equilibration time, viewing time, and tear-down time. You should plan on committing at least a couple of hours to each viewing session. If this doesn't seem realistic then a big telescope is not for you (or you just need an observatory to house the telescope).

Pros:
This telescope will cure all but the most severe forms of aperture fever.
This telescope will allow you to see the Great Orion Nebula in natural color.
This telescope will allow you to view (and see) objects without averted vision.
This is definitely a telescope for deep sky enjoyment --- realize dust lanes instead of faint fuzzy blotches.