Apo-tmosphere: Gutekunst ADC Review
Sep 23 2015 12:18 PM by pbsastro
Optolong LRGB Filter Testing and Comparison wit...
Sep 22 2015 02:41 PM by turbo399
First Light Review: Teeter Custom TT Planet Kil...
Sep 04 2015 01:57 PM by Zellmer
The Baader Planetarium Morpheus
Aug 20 2015 11:45 AM by wapaolini
Categories See All →
- CN Reports
- User Reviews
- How to . . .
- Observing Skills
- Astronomical History
- Optical Theory
- Vision and Related Experiments
- How to Gain the Support of your Family for your Astronomical Pursuits
- Evaluation Tips
- Special Events
- The Elements
- New Articles in [!monthname!]
- Telescope Articles
- Submit a Review / Article
- Monthly Guides
- Behind the Scenes
- About Us
- Copyright ©
- Terms & Conditions
- Tiny Eyes on the Skies
- From the Editor's Desk
- What's Up . . .
- The Light Cup Journals
- Who is this Super Light Cup?
- Cloudy Nights T-Shirts
- Imaging Contest
- Small Wonders
- Previous Imaging Contest Winners
- This Month's Skies
- Mike's Corner
- The Cloudy Nights Friends and Family Discount
- Uncle Rod's Astro Blog
- Fishing for Photons
- Binocular Universe
- Article Submissions
CN Reports Review: Orion SkyQuest XX14i
Voice your opinion about this subject in our forums
CN REPORTS Product Review
An In-Depth look at the Orion SkyQuest XX14i IntelliScope 14 inch f/4.6 Truss Tube Dobsonian
Available from Orion Telescopes, Watsonville, CA MSRP: $1799.95
Image 1: XX14i Setup
The Dobsonian revolution triggered the creation of number of larger aperture altazimuth Newtonian telescopes that have pushed amateur observing to limits unheard of just a couple of decades ago. With much larger apertures came the need to abandon the solid tubes of the original Dobs and go with the more portable and easier to setup truss-tube altazimuth Newtonians first made popular by Sky Designs and Obsession. Now, Orion has thrown its hat into the ring with its new SkyQuest XXi line of 12 inch and larger truss-tube Dobsonians. One of their newest is the XX14i, a 14 inch f/4.6 Newtonian with the “Intelliscope” Computerized Object Locator (COL). The instrument has both good and not quite so good qualities to consider about it.
And now, a message of caution. For those not used to the world of large aperture portable Dobs, one thing to understand is that, despite their looks and ability to break down into smaller pieces, these scopes still tend to be physically BIG and heavier than they look. One should know exactly what one is getting into, as there is nothing worse than buying a scope you will not use often due to the hassle of moving it or putting it together. Sometimes a choice of a slightly smaller aperture can reap big rewards as far as the amount of use you might get from a given instrument. However, if you still really want that big aperture (and you know you do!), then read on...
Product Description: The XX14i is a 14 inch aperture f/4.6 Newtonian with a modified truss-tube on an altazimuth mount. It is somewhat 'beefy' in structure and mass, using more metal in its construction than some other truss-tubed Dobs its size. Assembled, the scope stands a maximum of about 67 inches high with a maximum eyepiece height of about 63 inches when pointed straight up, and a minimum eyepiece height of about 28 inches above the ground when the scope is pointed towards the horizon. The complete optical tube assembly is about 61 inches long, a bit over 16 inches in diameter, and weighs in at just over 70 lbs. The scope when fully horizontal requires a clearance radius of about 45 inches from the azimuth axis in order to turn 360 degrees. Thus, those considering this scope for use in an enclosure like a dome would be best to consider one at least 10 feet across for good clearance. When fully assembled, the weight of the entire telescope and mount is nearly 120 lbs, which is about 40 lbs heavier than the 12 inch Meade Lightbridge but only eight pounds lighter than the 16 inch Lightbridge. While the assembled telescope is pretty heavy, it breaks down into a number of smaller easier to manage segments for transport. The segments will be described separately. Below is a summary of the basic data for the reviewed XX14i telescope:
14 inches (355.6 mm)
Measured Focal Length
1638 mm (f/4.6)
Secondary Mirror's Minor axis
3.15 inches (80mm, or 22% central obstruction).
Max. Assembled Height
67 inches (1702 mm)
120 lbs (54.5 kg)
Assembled OTA length
61 inches (1549 mm)
2-inch dual speed.
Open-faced Altazimuth with friction bearings.
Max. Eyepiece Height
63 inches (1600 mm)
9x50 “straight-through” optical finderscope.
Image 2: XX14i Lower OTA Section
Optical Tube Assembly (OTA) Lower Tube Section: This consists of a can-like portion made of rolled thin steel sheeting between ring-like heavy duty aluminum end castings. The lower OTA is about 16.5 inches across, 22 inches long, and weighs about 55 lbs with the rear counterweights installed. The forward end has angular attach point fittings for the truss tubes, while the aft end is an integrated mirror cell/aft end ring, containing the primary mirror, three detachable counterweights, and a cooling fan. On opposite sides of the lower OTA are two large cylindrical plastic bearing “shafts” for the altitude axis. The weight of the lower OTA alone made me construct a small wooden transport platform with four very large casters to move it around more easily. A very nice heavy plastic dust cover is provided to seal the front end of the lower OTA when it is being stored, and a second one is also provided for the upper OTA section when the entire optical tube portion of the telescope has been assembled but is being stored or protected when not in use.
Image 3: XX14i Mirror Cell
The primary mirror cell of the review instrument is a nice 18-point suspension cell with cork backing on the support points of the triangles and three mirror clips that were made from rubberized metal washers. The side support for the mirror were cylinders of what looked like nylon, and the whole mirror was very well supported without any pinching. There are three spring-loaded collimation screws with large metal knobs and separate locking screws around the outer portions of the mirror. The springs seemed to be a bit on the light side, but with the locking screws engaged, the mirror cell was solid. The cooling fan is a thin three inch square computer fan that is placed to blow air directly onto the middle of the back of the primary mirror, and runs off of 12 Volts DC. A separate 12 VDC battery pack for eight “D” cells is provided that has a four foot cord and a plug for the battery jack on the fan. This pack is equipped with a strip of Velcro so that it can be attached wherever it is convenient.
The primary mirror is two inches thick, weighs about 23 lbs, and is coated by 94% reflectivity “enhanced” aluminum (silicon dioxide overcoat). It also comes with a center point marker on its optical surface for collimating, but the mirror I got is not quite perfectly round. The lack of color in the glass seems to indicate that the mirror is indeed made of a lower expansion glass, as is stated in the manufacturers literature. The focal length of the reviewed telescope's primary mirror was measured to be about 1638 mm, which is only 12 mm (0.7%) less than the manufacturer's 1650 mm specification. The optics are stated by the Orion to be “diffraction limited”, rather than being given a specific wave rating (more on this later).
Image 4: XX14i Upper Tube Section
OTA Upper tube Section: This portion is 16.5 inches across, 8.25 inches high, and contains the focuser, finder scope mount, spider, and secondary mirror. It weighs a little over nine pounds and has construction similar to that of the lower OTA section with thick metal end ring castings and the attach points for the trusses. The interior of the upper and lower OTAs are both painted a very dark gray color rather than being a fully non-reflective flat-black finish. The focuser is a fairly nice 2” dual-speed focuser that has a focusing range of from 3 inches to 4.5 inches above the surface of the tube. The focuser was also provided with a 2” to 1.25” adapter that was somewhat thicker than it needed to be and was not threaded for filters. The finderscope was a 9x50 “straight-through” finder with the standard Orion “gasket and 3-screw” bracket plus small footprint dove-tail attachment for quick and easy removal prior to disassembly. A small extended knob for moving the scope was also present on the upper OTA. The 4-vane spider uses tapered 0.8 mm thickness vanes and tensioning adjustment knobs on the outside of the tube. The secondary mirror has an 80mm minor axis size (3.15 inches) and was secured by hard double-sided foam tape adhesive onto a solid “45-degree sliced” metal cylinder about 45 mm in diameter. This cylinder is then held in-place by a central screw surrounded by three recessed hex-head screws for collimation adjustment.
Image 5: XX14i Trusses
The Trusses: The two portions of the optical tube assembly are connected by four truss-pole assemblies. They are made of eight aluminum truss poles about 32 inches long and one inch in diameter, which are mounted in somewhat triangular pairs around the outer portion of the tube. Each truss assembly has two poles connected together at the upper end in a rectangular “truss connector” mounting plate. The lower ends of the truss poles are flattened and have captive bolts with a large easy to use knobs mounted near the ends, as well as one captive bolt mounted in the flat rectangular upper plate. The truss connector mounting plate allows each truss tube to pivot over a fairly decent angle. This lets them to be right next to each other when stored, or at the proper distance on the far end when connected to the telescope tube (also aids in getting the truss coupled to the upper OTA).
Image 6: XX14i Mount
The Mount: As with many of the Orion Dobsonians, this is also a simple altazimuth rocker-box mount made mostly of hard “composite wood” material that has a very good black laminated finish. Indeed, for a while, I was unsure whether it was actually real wood, as it has a similar density and strength. The edges were very sharp and clean, with no signs of flaking, and all of the holes drilled into the material were smooth. When assembled, the mount stands about 27 inches high and weighs about 45 lbs. The completed mount has captive bolts with knobs, allowing the azimuth disk and ground board to be disconnected from the rest of the mount. The upper “rocker box” section of the mount also can be easily broken-down into three smaller fairly flat segments for more compact storage. A large thick plastic handle is provided for the rocker box to assist with lifting, along with a small eyepiece rack for temporary eyepiece storage. The tube assembly with its large plastic altitude shafts is supported on the mount on four small round plastic knob-like bearings that are located inside of the forks of the rocker box rather than being part of the “open-faced” designs that Orion usually uses. The Intelliscope encoders for altitude and azimuth are also internally mounted, and the cabling is provided with standard phone-jacks and Velcro for easy disconnect when the base is totally torn-down for storage or transportation. The Intelliscope hand unit also connects to a port on the outside of the fork portion. Unlike some Dobsonians, the telescope tube cannot completely swing through the fork on past the zenith due to the restrictive nature of the rocker-box, which is only open on one side.
The base of the mount is a large disk about 29 inches in diameter which is coupled to the triangular ground board by a single small central azimuth axis bolt. The small size of this bolt and the “composite wood” material around it is a potential concern, so care should be taken when transporting the disk-like base and ground board sections on their sides. The underside of the disk has a wide track made of Ebony Star to bear up against the three nylon bearing surfaces located on the ground board. The triangular ground board (“base plate”) also has three small furniture “feet” to supply a little ground clearance for the entire scope.
Assembly: The XX14i required considerable initial assembly work to get it ready for regular use, but fortunately, you have to do most of this only one time. It took a friend of mine and I over three hours to get things finished. However, for once in my amateur “life”, the assembly instructions were pretty clear and easy to follow. The instrument comes in four rather large packages for the OTA, the mirror and cell, and the mount components. No exotic tools were required, although there were a few little jigs provided for part placement. I would have liked a few extra spares for some of the screws and washers, but everything needed was present in the boxes. I really liked the way the primary mirror was packaged, as it came already installed in its cell inside of a custom styrofoam holder that mated well to the outer box. It was a bit of a headache to install all eight screws to connect the primary mirror cell to the lower OTA (why not just six screws??), but it got done without losing even one screw (whew!). Probably the hardest thing to do when putting the mount together was to install the altitude encoder of the Intelliscope, as there were some small parts to play with. There was an addendum in the little Intelliscope box that had some changes over what was in the manual, and there was a small white nylon spacing bushing for the altitude encoder that got temporarily lost (the encoder won't work without it and it isn't captive), so that gave us a few headaches when we tried to test the Intelliscope. Much of the hardware on the scope however is captive, which is a nice touch. However, both the altitude locking knobs are not captive (and one has that nasty little elusive nylon bushing that likes to fall off). That little white bushing for the altitude encoder can easily come off in the dark and get lost here, rendering the encoder useless. Looks like somebody in the Orion design room went to sleep here after doing such a good job with captive hardware elsewhere. I got a separate box to hold the non-captive items and made sure they were all there prior to getting the scope out.
Once most of the hardware was in-place, it was time to put the trusses on the lower Optical Tube Assembly (OTA) and connect the upper OTA to ready the scope to go outside. This turned out to be not so easy at first, even with two of us (one holding, the other messing with the knob-like captive bolts). The upper OTA is fairly heavy (9 lbs), so it took some wrist power just to hold things in-line enough to allow even one attachment knob to go into the little hole. Indeed, I was used to the somewhat lighter upper tube sections of the 12 inch Lightbridge or 12.5 inch Portaball and how they go on their truss tubes, so this took some getting used to. The upper OTA has metal “guides” on the outside that ended up getting in the way a bit. Indeed, the biggest problem was the fact that when trying to get the truss captive bolts into the holes on the upper OTA, you couldn't see what you were aiming at very well due to the presence of the big rectangular truss connector mounting plate. It was definitely a struggle for a single person to do it at first, especially while watching out for the unprotected secondary mirror in the middle of things (get something to cover that mirror during setup if you can).
Image 7: XX14i Trusses in Scope
After using the scope in the field and practicing in my living room, I finally came up with a system for getting things connected that seems to be workable. The first thing to do is start putting the trusses on the lower OTA so that they are just barely connected to the lower tube assembly loosely and so they are all somewhat tilted back away from the axis of the tube, almost like a flower petal opening. Bring in the upper OTA and tilt it up slightly so that it mates with only one of the truss end plates. Then connect the truss bolt loosely to the upper OTA. Once the first truss is coupled to the upper OTA, half the battle is won. Then, go to the opposite side of the tube and connect the truss on the other side to the upper OTA, but again, KEEP IT LOOSE! The looseness allows you to move things around a bit while connecting the hardware and is mentioned in the manual, but the backwards tilt of the trusses and the slight upwards tilt of the upper OTA are the keys to getting things started. Then, proceed to loosely connect the other two truss assemblies to the upper OTA, and when completed, tighten all the bolts on the trusses so that the tube is a firm structure. Once I had practiced this a number of times indoors, I could easily put the telescope tube together by myself, although when doing this in the field, I still recommend using a lot of light on the upper tube to see what you are doing.
The scope's tube full assembly can be lifted and placed onto the altitude bearings, but some people may want to just put the lower OTA on the mount first, lock the altitude tensioning knobs, and then attach the trusses and upper tube assembly. The fit of the lower OTA into the mount can get a little wonky, in that sometimes it is possible to get the scope into the rocker box but not properly settled on the actual bearings. Sometimes it hangs up on the little “vertical stop knob”, on some of the nylon spacers, or on part of the altitude encoder wheel, so be careful here.
The Shroud of Orion: Does this scope need a shroud? Yup, it does help things. The interior of the tube is not quite as dark as it might be, so I would recommend some sort of covering over the trusses to keep light out. Orion's optional rather “stretchy” shroud (a big elastic black thing) is a bit on the pricey side ($80), but it works fairly well. However, it can be a bit of a pain to get it on, as it has to slide over the front of the tube and down over the focuser and onto the trusses (and the fit is rather tight, like that of a long stiff stocking). Putting Orion's shroud on the trusses first and then trying to attach the upper OTA is a nightmare, so don't bother trying that. I might suggest just a dark cloth that unrolls and then attaches to the outside of the trusses using cloth loops or Velcro, but if you don't want to do this, there is always the Orion shroud. Once the shroud is in-place, you can attach the finderscope to its dovetail mount.
Up and Running: the Questions Start: Once we got the scope together and moving in my living room, we made sure everything was in-place and working before removing the tube and getting things moved outside. One of the first things I noted Orion doing wrong on the design of the XX14i was the dove-tail base of the finderscope''s bracket. Its open end is downward, so that if the screw holding the finder bracket isn't absolutely tight, the finder and its bracket can occasionally, with a slight bumping of the tube, slip out and fall to the ground. It only goes in one way, so this little “gremlin” kind of surprised me when the finder+bracket abruptly fell off and hit the thick carpet of the living room floor! Orion definitely needs to redesign the dove-tail with the stop on the back end, so that if the screw is not super tight, bad things won't happen.
I had to exert myself a bit to lift the entire mount intact out the front door and to my driveway. I soon learned to remove the upper rocker box assembly from the base disk and carry the two out separately (you have to watch the cables for the Intelliscope wiring however). The same goes for the full OTA tube (put it together outside), although that night, John and I together carried the tube outside fully assembled. Once again, as we set the tube into the rocker box, the thing got skewed a few times and we banged one of the tube's attached shafts against the disk of the altitude encoder more times than I would like (it is a little fragile). This could be a potential destroyer of the altitude encoder, so that was problem #3 with the XX14i design. Finally, we got the darn thing in right and put the two tensioning knobs on the sides of the rocker box to secure things.
Once the scope was settled, I started collimation. The scope includes a little eyepiece “cap” with a small center hole, but this is definitely not enough for a big f/4.6 scope. We used an Astrosystems “Light Pipe” and got down to business. The secondary adjustment hex-head screws were so tight that we almost broke them trying to get them loose enough to adjust. They were tight enough that they scored the metal on the top of the secondary mounting housing, so some over-anxious factory worker obviously had eaten their Wheaties that morning! The secondary had been mounted off-center from it geometric center, which is normal for large fast Newtonians if full field illumination is required. However, the amount of off-set or “drop” used here was a little more than is actually required for this layout. This forced me to get the secondary pulled up about as far in the front OTA as it would go just to get it properly centered in the focuser and “light pipe” collimation tube. However, after this, I didn't have a lot of trouble getting the secondary lined up pretty well, thanks to a nice center mark placed on the primary by Orion. The primary was fairly easy to align, although again, the secondary offset made this a bit of a “by guess and by gosh” sort of thing. The final collimation was done on a star, and once collimated, it stayed pretty much dead-on at all times. The finderscope was also easily aligned with the main scope, and there is also room enough on the upper OTA to mount my Telrad.
Optical Performance: I was a little surprised to see two eyepieces included with the scope, as many big Dobs come with none. They are a 2” 3-element 35mm “EasyView” eyepiece and a 10mm 1.25” Plossl. Now 3-elements probably isn't really enough to properly deal with a f/4.6 light cone. That showed immediately, with the 35mm displaying nasty astigmatism and larger star images in the outer parts of the field. Fortunately, in addition to my own eyepieces, I had Mr. John “Have Eyepiece, Will Travel” Lammers next to me, so in went his Paracorr and my 24mm Panoptic. Wow, the moon looked pretty nice, but the heck with it, on to Jupiter and a lot more power. The seeing was quite good and the view of Jupiter was nice with considerable detail, but once I got to around 238x, thing started to look a little funny, mainly with the moons of Jupiter. They did show nice disks, but precise focusing was harder, and during focusing, they seemed rather “hairy” on one side of focus. This sent up alarm bells all over. Putting the scope on some stars and cranking the power a bit more showed easily visible spherical aberration and clear signs that the mirror was undercorrected (ie: not enough glass removed from the middle portions of the mirror during figuring). The Ronchi grating in particular showed some mild but definite curvature of the bands, especially towards the outer portions of the mirror. Later, I made up a 33% obstruction from some cardboard and put it over the center of the spider to do Dick Suiter's “breakout” star test. The test is a little hard to get exact results from, but the ratio I got was nearly 2.5 to one, which is indicative of something a bit greater than ¼ wave of wavefront error. With the time getting late, we called a halt to the initial tests, as I had a lot to think about.
Mirrors On the Bench: The nagging suspicion that the primary mirror of the XX14i might not be quite “diffraction limited” brought back painful memories of another time 25 years earlier when I got “saddled” with a rather bad 2nd-hand Coulter 10 inch f/5.6 mirror. That 10 inch was really bad (undercorrected and very rough), but at least it taught me the value of learning how to bench-test mirrors properly. This time, I was ready, so I pulled the lower OTA out to my primitive test bench, dusted off the knife-edge tester, and started making a 5-zone Couder mask. Once on the bench, the mirror showed a beautifully smooth and regular figure with nice shadows, which was very reassuring. However, when I got to entering the test readings into the computer and looking at the results, that sinking feeling in the pit of my stomach from 25 years ago began to re-emerge.
The term “diffraction limited” has been used by some telescope makers to describe how the optics perform, but what it exactly means has never been properly settled upon. Some link it to the old ¼ wave (peak to valley) Rayleigh limit for wavefront error, while others link it to the Marechal limit of 1/14th wave RMS wavefront error. Still others use the Strehl Ratio of greater than 0.8 to describe “diffraction limited”, so there is a lot of uncertainty here. In my case, I didn't expect this telescope to have anything even close to “premium” optics in quality, but I was expecting a mirror that was at least one quarter wave p-v. However, my tests clearly showed otherwise. The peak to valley wavefront error on the very first run was 1/3.2 wave, while the RMS was around 1/10th wave. I did another test run and got slightly better results (1/3.3 wave P-V, RMS 1/15th wave), so after averaging, things still didn't look all that good on the peak to valley end. I put up a question on Cloudynights as to what I should do about this and Orion abruptly contacted me, asking for the mirror back for testing. Once back in California, they reported an interferometry test which indicated a 1/3.4 wave p-v figure, a 1/17th wave RMS, and they said that the mirror “is within our expected (and advertised) quality”. To Orion's credit, they did offer me the option to send the entire telescope back for a refund (minus the shipping charge), but I told them to send me the original mirror and I would deal with the problem myself. I eventually got the mirrors to a 3rd party professional who produces high-quality custom large telescope optics, and his test results (1/3.1 wave p-v, 1/12.8 wave RMS tested over seven zones) basically confirmed mine. Indeed, the optician tested the secondary as well and found it to be only slightly convex (between 1/5th and 1/6th wave), so at least that mirror met my definition of diffraction limited. Now I have heard from others who are perfectly satisfied with the optical performance of their XX14i scopes, so without their instruments to compare directly, there is some question about whether the mirrors I got were typical. However, the plain and simple fact is that the primary mirror I received in my XX14i was worse than the Rayleigh limit of one quarter wave p-v. In my case, I would have to call what I got “mediocre”. This eventually lead to my decision to have both mirrors refigured by that same professional optician who provided me with a 3rd opinion on quality.
Back Under the Dark Sky: While waiting for my professional mirror maker to get some time in his schedule to tackle my mirrors, I put the scope through its paces both on my driveway and at my favorite dark sky site. Overall, the scope performed fairly well, with the weight of the whole thing being the only major difficulty (and not exactly a huge one at that). I could generally set the XX14i up in about ten to 15 minutes depending on how many trips I had to make back into the house, as I kept it mostly torn down into its major components for transport. Cool-down time wasn't exactly a huge problem, especially when the fan was used, but I did have to allocate some time for that to happen. Indeed, on one warm humid evening, I had to wait even longer, as the “cool” mirror promptly fogged over when brought outside! During one test, we had a transit of Io on Jupiter, and I watched eagerly as Io's little yellowish disk remained visible as it crossed onto the planet, followed by the “huge” black spot of its shadow taking a bite out of Jupiter's limb. At the same time, John Lammers had his 8 inch f/5 with its set of custom mirrors on Jupiter at about the same power, and the difference here was telling. He couldn't see the disk of Io very well once it got onto Jupiter, but the color contrast of his view of the cloud detail was actually slightly better than in the XX14i. There was a subtle contrast difference, but John's 8 inch contrast was bettering the 14 inch by a little, even though the 14 was often resolving some finer-scale detail. Some of this can be explained by the better figure of John's custom (1/20th wave p-v) mirrors, so it was to be expected. Still, it was nice to be seeing at least some rather fine detail with that big 14 inch mirror.
Mechanically, the XX14i moves very well, with smooth altitude movement. With just a little tension on the altitude axis, the scope held about anything we could load into the focuser without sinking, including my 2” 14mm ES100 eyepiece, the 2” 2x Powermate, and John's Paracorr. However, the three counterweights on the back of the mirror cell must be installed for the scope to even come close to balancing. Even with the counterweights, the scope was very slightly nose heavy with the altitude tensioning locks fully disengaged. The azimuth movement was smooth but took notably more force to make the scope move in azimuth than with the altitude axis. However, I still had no trouble at all manually tracking Jupiter at powers up to 430x. Indeed, this stiffness is a help under windy conditions, as the scope stays put somewhat better than other Dobs that have smoother or looser azimuth movement. With its large footprint, the XX14i did not suffer from excessive vibration, as damping times were around three seconds or less. Most of the vibration was in the altitude direction, which is expected considering the design. The focal point of the telescope was exactly even with the 2” surface of the focuser when fully wracked inward, possibly due to its focal length being slightly shorter than the 1650 mm specification. This did cause a focusing problem with some Barlows and a few of my eyepieces that have extended “Smyth” lenses (my Speers Walers and my binoviewer for example). Indeed, the 2” to 1.25” adapter added to this problem, as it was too thick and was not threaded for filters (a pain at times, as I use mainly 2” filters). I may have to visit a machinist to have the trusses shortened slightly, as the mirror cannot be moved very much farther forward in its mount. I ran the cooling fan, and it did seem to help without inducing any significant vibration even at some fairly high powers.
On deep-sky, the 14 inch really went to town. People sometimes say that 14 inches is a “sweet spot” in usability, and I heartily agree. It is large in aperture but not large enough to keep it from getting pulled out for use regularly. Indeed, I never needed even a step stool to view through the scope, as the eyepiece height was just fine. Even from my driveway, I could see both of the main dust lanes of M31, and outside of town, what I saw was incredible. M31 was a whole new galaxy with loads of light and dark detail that I had previously noted only in photographs. Seeing the detailed spiral arms of M33 with direct vision was also a treat, as was observing the wealth of fine patchy detail in that galaxy that gives it the name “the Pinwheel”. I had an “eyeful” of the Perseus galaxy cluster, with nearly two dozen tiny very faint fuzzy spots being visible in the field at 117x. The faint wreath-like outer shell around M57 was quite easy with my NPB filter, and for once, M57 showed a bright bluish color easily seen with direct vision. The Crescent Nebula was also highly detailed, and I ran into a nice red carbon star (the variable RS Cygni) in the area just by accident. I went up and down the Milky Way, getting almost a perfect power setting (117x) using only my Explore Scientific 100 degree 14mm eyepiece. I didn't bother with hooking up the Intelliscope, as with the finderscope and my years of star-hopping experience, I could find about anything I wanted to go after. Globular clusters were wonderful in the scope, although seeing prevented me from fully diving into them at the really high powers I like to use. I even went a little silly and put in my 40mm MK-70 Konig and had all the Pleiades nicely in a 1.6 degree field of view (but with an 8.7 mm exit pupil)! Indeed, I visited so many things that quickly I lost track of time. The scope was simply fun to use even without firing up the Intelliscope option, with the only thing missing being my Telrad (I have yet to pull it off my 10 inch).
Image 8: XX14i Intelliscope
The Intelliscope: This item almost needs a separate review. With the XX14i, the only thing I would be losing over my Go-To NexStar 9.25 GPS SCT would be tracking, as the Orion Intelliscope could still fill-in as a finding unit with me doing the manual labor instead of electric motors. Basically, what the unit does is sort of “point you in the right direction”. You enter the object's identity from the Intelliscope's database of over 14,000 objects and then start moving the scope, with little arrows on the display window telling you which direction to go and numbers showing how much farther you have to move the scope to reach your desired object. The Intelliscope hand unit itself is a fairly light rounded black box about 5.5” x 3.5” x 1” in size attached to a coiled cord about two feet long that can easily be stretched to nearly six feet in length. The cord plugs into a phone jack on the side of the rocker box, and Velcro is provided to hold the hand unit anywhere that is convenient. There is also an RS-232 port on the top of the hand unit for interfacing to a computer (RS-232 cable is not provided). The front face has a small back-lit LCD display window and a set of 16 illuminated buttons to control and select what you want to do. The unit is powered by a single internal 9V battery with no direct ability to run it off of an external DC source. The unit does shut itself off after 50 minutes of non-activity to prolong battery life, and if it turns off, you have to go through the complete alignment routine from scratch once again. These little 9V “transistor radio” batteries don't exactly have a huge capacity, so be prepared with some spares if you are out at a week-long star party or observing under cold conditions.
Alignment of the Intelliscope is actually easier to do than the procedure I use for my NexStar 9.25GPS. You have to set up the scope vertically at the start so that it points towards the zenith, and then, you are given two stars to find as alignment stars. You move the scope to precisely put the first star in the center of the field, hit ENTER, and then move to the 2nd star to put it in the field center and hit ENTER once again. The controller then gives you a “warp factor” which is an error output telling you how closely you have aligned the Intelliscope. A warp factor of 0.5 or less is what you are aiming at, although I still managed to get a few objects at the edge of the field with a warp factor of 1.0. Most of the time, the Intelliscope was able to get the XX14i pointed to within half a degree of the desired object, so it did work pretty well, at least at low power. You can also do a “realignment” on an object or star you are currently viewing, which can improve the accuracy of the pointing in a limited area of the sky. One really nice feature of the Intelliscope is the “Identify” function, which, if you stumble upon an object which you are unfamiliar with, will often be able to tell you what that object is. The unit also allows you to display the celestial coordinates of where the scope is pointing, so you can use that to find objects not in the Intelliscope's database if you know those coordinates. The telescope can find the planets, but only if you input the current time (and it loses that time if you shut the Intelliscope off). You can also input up to 99 “User” objects that may not be in the database.
The biggest problem I had with the Intelliscope was that Orion chose to make the illumination color of the window a nice green hue! Some of that illumination also leaks underneath several of the buttons as well (the buttons also have red back lighting). A dim deep Red is the color that has been scientifically demonstrated to have the minimum impact on night vision for astronomical observing. The brightness of the display can be adjusted over five levels, but the dimmest two can make it hard to read the display and some of the buttons. Unfortunately, the lighting cannot be shut off without turning off the Intelliscope altogether. If Orion had allowed the back lighting to be shut off, I could have at least used a dim red flashlight to operate the unit, but it was not to be. The use of green LEDs by Orion has irritated me a little before, but on this “advanced level” telescope (Orion's term, not mine), it kind of makes me wonder a little as to who they think will be using this unit. In any case, this color may make me somewhat less likely to use the Intelliscope in the future when my full dark adaptation needs to be maintained.
Summary Evaluation: Well, for me, the SkyQuest XX14i was a bit of a mixed bag. The scope does work (indeed, much of the time, it worked pretty well), but it does have its problems. The main ones were: it is a little heavy, the upper tube assembly can be a little awkward to attach to the trusses, and the primary mirror was not up to the Rayleigh limit wavefront error standard of one quarter wave p-v. Probably the most significant problem was the figure of the primary mirror, as it was the one that got much of my attention when reviewing the instrument. While a mass-market optical system of this size and relatively modest cost cannot be expected to be all that close to “premium” quality, it should have at least easily met both the Rayleigh and Marechal standards. Hopefully, others who get this model will have somewhat better luck than I did with the optics, but the mirror's figure did tend to spoil my experience with the XX14i. I should soon have the refigured primary and secondary mirrors back from the optician (they both *will* be premium mirrors now), so I may look upon the scope in a somewhat more favorable light in the future. Until then, here are the “grades” I give the SkyQuest XX14i:
B- (could have been better both in weight and in the ease of setup).
B+ (nice finish, all hardware went in correctly, good instructions).
C– (primary mirror did not meet the Rayleigh ¼ wave p-v limit).
B (focal point a little low in the focuser, secondary mounted too far off-center)
B (a little harder on azimuth, but still easy to move).
B+ (3-second damping time, nice wide base).
B+ (nice, but could have been a little lower in profile with better 1.25” adapter).
B+ (functions well, but has green back-lighting problem).
C+ (3-element 35mm eyepiece performs poorly at f/4.6).
B+ (a 14 inch aperture with COL for less than $1800).
Conclusion: The Orion SkyQuest XX14i Truss-tube Dobsonian is a fairly nice large aperture instrument for the amateur who needs something a bit bigger than what is usually offered by the solid tubed telescopes.
- Stacy, Starkid2u and tim 57 like this