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Orion XT-8 |
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REVIEW ARCHIVES Refractors Barlow
Lenses LINKS FAVORITE LINKS NASA
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I bought an Orion XT8 Dobsonian (Newtonian) two months ago. The cost was $499 from Orion. (www.telescopes.com). This is my first "real" telescope since age 12 in 1957. I decided of late that I wanted to see some of these beautiful sky objects for myself and since I am not interested in photography (yet) I chose a dob that wasn't to large to handle plus not having even looked at the night sky through a small scope I did not know how much aperature I would need. I live four miles from a town of 10000+ population but have dark skies from the north around clockwise to the southeast. Well, the telescope arrived in excellent condition via UPS. The tube and small parts including the 25mm and 9mm plossl eyepieces were in one long box and the dobsonian mount in another square flat box. The primary and secondary mirror, focuser and side bearings came installed. I had to assemble the base and install the finder scope. The instructions were excellent and the XT8 went together without a hitch. The base consists of predrilled 3/4 inch particleboard. All the holes lined up perfectly. An allen wrench is provided for installing the screws in the base. A couple of wrenches for the center bolt in the base, a phillips screwdriver and the supplies allen wrench are all the tools needed. There are white plastic pads stapled in the cradle and on the base plate for smooth movement of the altitude and azimuth bearings and they indeed are smooth. The manufacturer was even careful that the staples were countersunk and didn't rub and scratch the bearings. Next is placing the tube onto the base and putting the springs of the Correct-Tension Friction Optimization system in place. These springs attach to the side bearings on both sides of the scope and stretch down to each side of the base. This keeps enough tension on the altitude bearings so the tube doesn't swing too freely. It also allows carrying the entire scope and base as one unit by the handle attached to the front brace of the base. I sometimes release one spring for a little freer movement in that axis. BE SURE if you do that you refasten the spring before carrying the scope again. This is firsthand experience talking and since there was three inches of snow on the ground there was no damage (whew). Before a good image can be seen a check of the collimation (alignment) of the optics is necessary. I can't stress enough the need for good alignment if you are going to enjoy what you see through the scope. Again, the instruction manual was very easy to follow. I also bought an Orion collimation tool and carefully placed a 1/2 inch piece of Scotch tape with a paper-punch hole dead center in it. I then placed that piece of tape with the hole in the exact center of the primary mirror. This allowed me to see the crosshairs of the collimation tool and can fine-tune the primary mirror collimation to bring the crosshairs to center of the mirror. Upon using the XT8 for a few nights it seemed that my collimation was changing more than it should. There is two things I did. First, I had read in a Sky & Telescope review the reviewer thought the primary mirror was flexing since it was not supported except on the edges and he noticed some astigmatism in the image. He put stacks of felt pads behind the mirror to the mounting plate. I was noticing some astigmatism and applied the fix. While doing so I found the screws holding the primary mirror clips to be a little loose so I took up the slack (but I did not tighten) and I am satisfied that things are better, however I don't know at this point which did the most good. I have had the scope out twice since I did this and had no changes in star image once the unit was cooled down. Before I bought this telescope I was not too interested in the moon and planets but wanted to see deep sky objects. However, I have changed my mind about the moon and planets after one evening of viewing them. The best views are near the terminator (edge of light and dark). The atmosphere was very stable that night and I enjoyed beautiful contrasty views at 133X. I was fascinated as I moved up and down the terminator. After the moon went down Saturn and Jupiter were up and I swung the scope to view them. Three bands on Jupiter were visible as was most of the Cassini division of rings on Saturn and one band on the planet itself. As for the deep sky objects I knew I wasn't going to see photograph like images and it wasn't even close. But open clusters are very beautiful with the stars being pinpoints of light. M13 shows many of the outer stars resolved. The best nebula so far (I have had the scope only two months) is M42 in Orion. It is more than just a hazy patch. M31, though, is just a hazy patch, a big one. I can't see any dust lanes. I have much of the sky yet to observe as the year progresses and am looking forward to using this scope. The scope is well built and went together well. I didn't spend a lot of money, I got a fair amount of aperture on a scope that is easy to use. The focuser is very good and no backlash. Eyepieces are good quality. I get good views with the stars sharp almost to the edge of the field. I think I got a good buy. Submitted by Joseph Yergler - Colorado The Review I
recently purchased the XT8 as my first serious home use scope. Previously
all my personal scope time was 15 years ago in college with a large motor driven
Newtonian design scope that had a meter or so of aperture. I was immediately
struck with aperture fever, however I soon discovered that there are two
classes of scopes in this area: 1)the ridiculously high 2) the ridiculously
shoddy. I finally settled on an Orion 16 inch Dob with great reviews for
only around 1000.00. Unfortunately this model was discontinued. As luck
would have it a local vendor (EP Roberts) in New Orleans had one model XT-8 in
his showroom (as of this note, the XT10 is backlogged until March). I
rushed down to New Orleans (2.45hr drive) to grab the scope before it was sold.
Success! Now
,down to the scope itself. During my several weeks of internet reviews and
window shopping in stores I felt I had fairly well known what to expect in the
500 dollar range-not much. What a surprise! this scope is well made of what
appears to be fairly high quality material for the cost. I have perused the
shopping lists for the do it yourself telescope makers and have a decent Viewing objects As
I mentioned before, it has been some time since I have had access to a yard or
so of shaving mirror, but I was impressed with the clarity of pictures in the
scope. at 133x , the Orion nebula and its greenish cast look awesome! Clusters
resolve fairly easily. I haven't found the need to use averted vision or to
jiggle the scope to cause objects to become more The one big gripe I have is the finder scope. I constantly have to set and reset it because of it working loose. Surely there has to be an easier way around this. Summary
Submitted by MORDED@aol.com The Review My scope arrived in two(2) packages. One package containing the base
had obvious damage. Upon opening it I found a part of the base was damaged. I called Orion and they shipped out a new base
overnight UPS. No questions asked, just shipped it. UPS dropped the ball on the
overnight shipping. It arrived a day late. Sat in Miami a second night. I guess that's the risk you take shipping thru 3rd. world cities. Submitted by Bill - bc37@aol.com - USA
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The Review