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Celestron Nexstar 11: 11" SCT With Onboard GPS "GOTO" System A "Mini Review"
Why a "Mini-Review"? One of the most anticipated scopes (according to the buzz on the Net and according to our Editor, Allister St. Claire) is the new Celestron NexStar 11. Allister asked if I could get my first impressions and some photos out as soon as possible. Therefore, this "mini-review" follows my first two full nights of use, and a more elaborate follow-up should be posted in the next month or so.
I am not a SCT fan (sorry, Rod) and where I have had the chance to use them, I was bothered by their lack of contrast and (at times) poor optics. I had a Celestron C-14 for a while, found its optics to be FAR better than those from its California rival, but found setup and cool down time to be just too much of a hassle. Since then, my deep sky observing has been limited to my Dobs. (Easier to set up and, with Rick Singmaster's Starmaster GOTO scopes, a pleasure to use.)
There has been much interest of late in the new Celestron NexStar 11, which promised to provide the ultimate in ease of use and setup by combining an onboard compass, GPS system, and a carbon fiber OTA. Since I am a boater who has been using a GPS system on my boats for several years, and knowing that a small and cheap GPS unit provides remarkable accuracy, I found this concept to be fascinating, and when Mike at Astronomics said "How about it Dave?" I said "Sure, maybe it will make me a convert.
The NexStar 11 arrived Friday morning July 13. UPS dropped it off in two boxes. When I came home, I saw the first problem right away.
The tripod came shipped in a box with it well-protected and held in by fitted inserts, top and bottom. The OTA and supplied equipment came in a single, thin-skinned cardboard box which, as I could see, had a large hole in it and the weave of the carbon fiber was visible from the outside.
My regular UPS driver is a 'pro' and pointed out to my wife when it was delivered that while it was marked as "delicate", the box was very thin and too flimsy to offer any real protection. I agree. I 'unpacked' it by simply reaching in and tearing the box open from the puncture. It came apart like tissue paper!
Next surprise. The OTA was not encased in foam or a packing insert like the C-14 is shipped. There was a foam square at each end and a little packing on each side. The eyepiece and the diagonal that are supplied were packed between the OTA and the end of the box, and the other pieces simply tossed inside the main box. Poor, very, very poor packing Celestron!!!!!
The tripod is secured by a simple strap, and opens up and is secured by a centrally located 'spider', as shown in the photos. It has no provision for leveling (which is technically not needed with this GOTO system) and takes only a minute to set up.
Once the tripod is set up, the OTA and its fork mount and electronics drop on a central pin to mate it to the tripod. There are three retaining screws that mount from underneath the tripod to secure it to the base.
Once on the base, the assembly is easily 'wobbled' with not apparent way to stop it, no matter how hard you tighten the spider or the retaining bolts. It never threatened to topple over, but even with the supplied vibration pads, the scope would wobble even with a light touch, something like a bowl of jello.
Another early owner noted this problem on SAA, and suggested the central pin may be too long or not properly aligned for the base. I am not sure, and while this did not really effect my viewing (there was little or no wind, and I didn't get much in the way of shake problems) it is a matter of some concern that I will take up with Celestron in the near future.
The finder (9X50) is your typical Chinese finder, and it too goes on very easily. The scope comes with a 40mm Plossl (not the best - and one of perhaps the worst- eps of this focal length I have used), a 1.25" visual back, a 1.25" diagonal (better than the ep, but not something I would rush out an buy), an AC adapter, and a set of vibration suppression pads.
The scope can be picked up and moved in one piece, but it is awkward moving it up and back. Mating the OTA to the tripod takes only a second, so the routine I have used is set up the tripod where you want to observe, drop the OTA on, and you are ready to roll in a minute or two.
First and Second Light:
For some strange reason, the weather seemed decent the first night the scope arrived. Set up the scope while it was still light on the observing pad near the lake, aligned the finder scope (quite easy to do on this scope) and then inside to wait for full dark. (Please note that since I observe sitting down, I did not extend the tripod legs.) When I went out an hour later, the scope had reached equilibrium and I powered up.
The NexStar 11 uses the same basic hand controller as the other NexStar scopes (see attached picture.) You can leave the controller in place or pop it out to work with, there being no real advantage one way or the other.
On power up in the GPS mode (the only one I have tried so far) the scope first searches for the GPS satellites and lets you know when it has located them and they, in turn, have located your telescope. (I have used a GPS system for quite some time. The routine this scope goes through will be old hat to other GPS users. And, like other GPS systems, the successive uses will show quicker response time as the unit has a better 'idea' of where to find the satellites after the initial start up.)
The GPS alignment procedure is like other NexStar systems, except you need not feed in the basic date as to location, time, do a rough "North align" nor level the scope. The NexStar 11 does all that for you, and fairly soon it goes to a rather obvious (read bright) alignment star and asks you to center it in the finder. (Making sure the finder is properly aligned is therefore important. I did that right off the bat, which seemed like a good idea at the time, and turned out to be one as the alignment proceeded.) Hit the key to indicate a successful first star alignment, and the system moves to the second bright alignment star, and bingo - that is it!
The motors are very quiet in my unit. Vibration was minimal, and the initial alignment was very close. The system placed almost all of the targets selected at or near the center of the 40mm ep (I tried to stay with ones that would be suitable for that ep and diagonal combination to give a fair approximation of what a user without his or her own additional equipment could expect out of the box.) I would give the GOTO system a B+ or even an A- minus, and was far more impressed with it than with the accuracy of the NexStar 4 I had tried. Adequate, but not as good as the 11 by any stretch of the imagination. I would say it was at least as accurate as my Meade LX200 7" Mak.
One thing that I did notice in comparison with the Meade was that the motors on this scope were much quieter. Again, this is typical of the Celestron vs the Meade as I recall hearing from others and from using the two systems at star parties or with friends.
The optics were fine when I first set up the scope, but the collimation seemed a tad off. I couldn't correct this the first night as the seeing was not good enough to let me crank up to enough power without the slight haze making accurate collimation impossible. The next night, following the procedure in the manual, it was a very easy task to tweak the collimation (it was only a tad bit off.) I would chalk that up to the state in which it arrived, or to the tender mercies of UPS. And, as I am a fuss budget on collimation, many would not have bothered to tweak it at all.
Once I did so, however, I can't say enough good things about the optics. Nice patterns on the star test (but, as I will confess, I am not a star tester of much skill, just enough to make sure the scope is properly collimated and has no obvious optical glitches.) As I said at the outset, I am not an SCT fan in general but the optics on this scope were as good as any SCT I have ever looked through. I have not had a chance to look through the ne plus ultra of Schmidts which, according to the experts, would be the Tak 225 or the Celestron 9.25. However, having looked through a fair number of 8 through 12" Meades, and having owned a C-14, this one was better than 90% of those, and equal to the rest. No obvious optical problems and the optics seemed smooth and crisp on a variety of DSOs. Double star splits (not normally the forte of an SCT) were clean and distinct. An firm "A" for optics.
I had a major problem with image shift and stiff focusers on other SCTs and on a few of the early and smaller NexStars I had tried. The focuser on this scope was very smooth and shift was minimal. Celestron has paid attention to this issue on this newest NexStar and I found it a pleasure to use.
The second night, I tossed the supplied diagonal and ep, and put in the Tele Vue Everbrite 1.25 and some of my Tak and Tele Vue eps. These eps and this superb diagonal brought out the best in the already excellent Celestron optics. Enough to make me an SCT fan, and ready to grow what is left of my hair and buy a hat so I can look like Rod? Not yet, but perhaps in a few months :-)
Another recent purchaser said he thought the mechanicals were rough on this scope. I wouldn't say that, but would suggest instead that 'utilitarian' would be a better description. The carbon fiber (not an easy material to work with) on the OTA was smooth and well-finished on my example. The dark grey finish on the metal parts was also nicely-done, if not glossy or a work of art like some of the more high end refractors I own. The scope does use a fair amount of plastic, including the base and the fork arms. This may not have the heft or the finish of the LX200 metal parts, but it contributes to the light weight and ease of mounting resulting from that light weight. (My LX200 Meade Mak was a moose, and a pain to move around as a consequence.)
One thought on GOTO systems in general and this one in particular at this point: The 'experts' say, why bother, a good amateur should be able to star hop or know enough about the sky not to need this crutch. If not, a good DSC system can work just as well.
Perhaps they are right, but the NexStar 11 is so simple to use and accurate that I found myself getting right to what I wanted to look at, and then on to the next target on my list without any effort at all. With the seeing marginal the first night, the NexStar 11 got me where I wanted to go in circumstances where I would have seen very little without a whole lot of effort and no doubt would have given up in frustration. So maximizing your observing time is a real benefit of this system and this scope. Set it up (a quick job with little effort) and hit the power switch - and then have fun.
My only real reservation at this point is the wobble which seems to be induced by the perhaps too long center guide pin. I will contact Celestron on this at once, but the 'fix' would seem to be easy and my initial use wasn't upset all that badly by this issue.
More (much more) later, but these are my first impressions of this much-anticipated product.
- rkstreet likes this