At this time I do not want to give a rating on the optics, mount and other for the 15" Obsession. I just want to give my initial impressions of the scope. I believe it will take about a year of use with this scope before I could give an honest rating on this equipment. I live in the Great Northeast and good to excellent seeing conditions are not common. It will be some time before seeing conditions will allow this optic to be evaluated. I have an observing buddy that has a 15” Obsession with a known excellent Nova mirror, which I will use as a reference.

I received my new Obsession with a Torus mirror back in October of 2002. The scope came just 7 weeks after placing the order. The crating, insurance and shipping cost was just under $400, which I thought was kind of high. This is the first new DOB I ever ordered so I really have no idea what the other DOB manufactures are charging for shipping. I must say that Mail Boxes Etc did an excellent crating and shipping job.

The first package I open was the Torus mirror. I was excited to see what kind of mirror specs I had gotten. I was shocked and thrilled when I saw the interferometric test results. I had a mirror with a strehl ratio of 0.994! I couldn't expect a better mirror. A couple of weeks later my bubble was burst with reports on the internet of a Torus mirror with TDE, poor optical performance and independent test results that didn't agree favorably with Torus's. At that point I became very skeptical about my mirror and mirror manufacturers and there claims in general. I no longer had confidence that I had a great mirror and only time behind the eyepiece will determine if I did or not.

Unpacking and assembling the scope was straightforward and uneventful. The design, finish and construction of the scope are very good. Much better than the Compact II Starsplitter I owned previous to this scope. The new spring loaded secondary collimation screws are an excellent design change and this makes collimating the scope a joy. By far this is the easiest scope to collimate precisely and easily. The alt/az motions are smooth and the scope is very well balanced. Once completely assembled the scope is beautiful, functional and extremely rigid and stable. I have noticed in some other DOB designs a lack of rigidity that would cause backlash in its motion and loss of collimation due to shifting truss poles. The 15” Obsession is rock solid in this aspect. The scope is also very compact when apart and fits easily in the back seat of my Toyota Camary. This is most likely the largest truss DOB that a strong and healthy individual can pick up and carry with no assistance. Also anybody over 5’ 10” will not require a ladder.

I have had the scope out only a couple of nights due to the great weather we have here in the Northeast. Sky conditions were fair to bad and therefore I could not evaluate the optics. My last scope was a 12.5” Starsplitter and so far the most obvious difference is the brightness and color of stars. Stars are much more brighter and colorful in the 15” Obsession. At this time I have no more feedback on the Torus optics.

Things I didn’t like about the scope, some are minor, are as follows:

1. The plastic standoffs for the secondary collimation screws are white and should have been finished flat black. This is most likely minor but some day I will do this myself.
2. The truss poles had very sharp edges on the inside ends. The tube cutter caused this edge when the tubes were cut and for the money these scopes cost the edges should have been finished off with a file. I did finish off the edges myself right away to avoid being sliced and bleeding like a pig all over my new optics.
3. The mirror cell sling design does have problems with holding exact collimation. The mirror can swing side to side and the belt at times seams to stretch and shrink. For the typical seeing conditions in the Northeast exact collimation is not that critical but when the seeing is good and you want to observe Jupiter or Saturn you better check your collimation. Again this scope is very easy to collimate.

My final comments are about previous reviews and comments about the 15” Obsession on this site. First of all I cannot believe any telescope review with just a few lines of basically emotional comments with a rating of 10. I think most people just get too emotional with their new telescope purchase and then their objectivity just goes out the window. There will always be problems with design, construction and workmanship with any scope no matter who makes it. If these reviews were truly objective they would point out these issues and you would never see ratings of 10. You cannot expect perfection from these scopes for the money they cost. Just remember that the Hubble’s initial cost was about a billion bucks and it had its share of problems.

With all this said, I hope for one day to witness jaw-dropping views of Jupiter and Saturn with this scope. The kind of views you read about on these discussion groups. Until then I’m going to reserve my final review and rating of the 15” Obsession for a later date.

UPDATE 8/7/2003

It has been over 10 months since I have received my 15" Obsession. After many months of observing, star testing and performing side by side comparing with another 15" Obsession with Nova optics and other large DOBs I came to the conclusion that I had a mirror with a significant turned down edge. The other Obsession with the Nova mirror that I was comparing with also had a turned down edge.

After weeks of being in a state of denial I finally contacted James Mulherin at Torus and discussed my findings with him. He was convinced that I really had a problem with my mirror and that he would take care of it right away. In less than 6 weeks my scope had a fantastic mirror that would focus bright stars to a fine point with only 4 diffraction spikes from the spider. I was very satisfied with the optic now, but I wanted to see Mars with it before I gave it the okay.

Observing Mars this year in any scope has been amazing so far. I have never seen so much detail on this planet until now. My new optics seemed to be performing as good on Mars as any other known good optics in my club.

The final test was at the Rockland Astronomy Club's summer star party in Savoy, Massachusetts. Here there were at least 50 or more scopes on the field. During the early morning hours of August 1 the sky seeing conditions become very steady for the Northeast. I was observing Mars with my 15" Obsession using a 2.5x PowerMate with a 13mm SW Lanthanum eyepiece. This gave me about 330 power. The images of Mars were amazing. Never saw anything like it in my life. People who came by to take a peek were so impressed that they were telling other people in the field to come over to my scope to take a look. Soon there was a line of people who wanted to look through my scope. Everyone who did come over were also amazed at what they saw. They were also saying to themselves that my scope was giving the best Mars images of any scope on the field. At that moment I knew I had a very good optic.

Later on that evening there was news of a 25" Obsession using a bino viewer with a Torus mirror that was giving even more impressive views of Mars than my scope. I went over to take a peek, but there was already a long line. I decided to came back later to look. By the time the line was gone also the seeing had gone. When I looked through the 25" it was a nice view but nothing compared to what I saw through my scope. After talking to several people who looked through both scopes it appears that about half were split between which scope had the better views.

Now you may wonder why I only gave the scope a rating of 9. I figure nothing is perfect and there will always be something better out there. In my book a 9 is about as good as it gets.

Overall Rating: 9
Optics:9 Mount:9 Ease of Use:10 Value:9
Weight: 10
Date: 08/07/2003 04:59:16 pm PST

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