Celestron22097 NexStar 127SLT-Mak Portable Computerised Maksutov-Cassegrain Telescope, Grey

This review is specifically for the Celestron NexStar 127SLT Maksutov Computerized Telescope. There are several reasons I went with the Maksutov design, rather than the refractor or Newtonian SLT variations. The Mak gives a better image across the field of view, without the coma of a Newtonian. The folded optical path results in a long focal length for the instrument, which is ideal for Sun, Moon, and planetary viewing. However it's not as long as a refractor. The Mak can still be used for observing deeep sky objects, such as the Andromeda Galazy (M31) and Hercules Cluster (M13). Just don't expect the views of a Dobsonian 'light bucket'. It's not designed for that.The compact tube size makes it much easier to handle and transport than longer telescopes. Being a closed tube design also means it more easily keeps dust and other debris out of telescope tube. As long as one uses the tube cover on the front, and eyepiece holder plug in the back when not in use, the telescope optics will require cleaning much less often than a typical Newtonian system. The closed tube also means no thermal tube currents to distort the image.The 127 millimeter diameter aperature equates to about 5 inches in size. While this is considered small in today's era of large Dobsonian monsters, the telescope system fits in my car, and is light enough that I can take it outside easily. I get more use out of this scope than my older larger Newtonian, mainly because this instrument is just so much easier to handle. The aperature size is quite sufficient to get good views of solar system objects. It's a bit tricky to focus, as the image will easily show any motion from the focuser knob, but this is mainly a mount limitation. Once focus is acheived though, and the scope settles down, the views are great. I've used the 127 SLT with a Celestron NexImage 5 camera, and FireCapture camera software, to get great images of Jupiter's moon eclipsing the disk, Saturn's ring system, lunar craters, and solar sunspot groups (with an appropriate glass solar filter mounted on the front). Using the camera is ideal with this telescope, as it makes it a 'hands-off' system.The other great feature is the fully computerized "Goto" capability of this telescope. Once the computer system is initialized, it is able to point the telescope to any object in the sky. (Yes, one can even enter arbitrary Right Ascension/Declination coordinates to point the telescope at.) The SLT came with the NexStar+ Hand Controller, which contains the object databases, and interfaces with the user via a red backlit LCD and a red lit keypad. The hand controller I got was not the absolute latest hardware variation, which has a USB port on it, so as to allow updating the firmware in the system via a PC. Instead, I received a slightly older version (2014) that still had the RJ45 phone jack interface providing an RS232 serial connection. (Older stock in the warehouse still?) This required a USB-to-RS232 converter to connect to my laptop to update the internal flash. While the internal motor controller was at the latest firmware revision, the hand controller firmware did need updating. The Celestron Firmware Manager, available onine at their web site, did the upgrade flawlessly.The one armed fork system that connects the tripod mount to the telescope tube contains the motor control system for the alititude and azmimuth DC motors, as well as monitors their optical encoders to keep track of position. This motor controller communicates to the hand controller via a coiled cable. There is a plastic holder on one of the tripod legs made for holding the hand controller when it is not needed.The weakest link in this system has to be the 'wobbliness' of the mount. With the legs fully extended, and the tripod standing on a cement patio, every gust of wind and and hand touch is transferred to the image view. It makes it quite difficult to focus well. However a few simple tricks can be used to lessen the effect. First, don't extend the tripod legs fully. The shorter the tripod legs, the shorter the time it takes to dampen out vibrations, and the sturdier the mount becomes. Second, adding a weight to the tripod helps provide more mass, and lowers the natural vibration frequency. I've seen a picture of one user placing a small sandbag on the central tripod tray to add stability. Third, place the tripod on dirt or sand. A cement patio is not the best foundation for the tripod legs. I have gotten much less image movement by pushing the tripod legs into the dirt in the lawn. Of course, Celestron does sell vibration dampening pads to help with this issue, but they are quite pricey according to my wallet.Now if you want to get a beefier mount, go ahead and spend another grand. Celestron has bigger mounts that are better. You get what you pay for. Just be prepared to lift that heavier mount. I'll stick with this lighter variation, and save my back. I can work around its limitations.Oh, and the eyepieces that come with the telescope are probably not the ones you will want for regular use. I already have a nice set of Plossl's that I obtained years ago. I recommend doing your homework and get the eyepieces separately. My lowest power eyepiece is a 40 mm, and I like the views it gives me in the 127 Mak.One bit of information you will also find useful relates to initializing the NexStar control system. The designers did what they could to make setup as easy as possible, within the budget they had. (I've also bought the SkySync GPS accessory to help make setup easier. However their StarSense AutoAlign product is the ultimate alignment tool, and costs nearly as much as the telesope itself!) Anyway, the more care you take in initialization, the more accurate the NexStar will be in finding objects. I know this, not just from using the NexStar+ system, but from building my own telescope controllers over the years from the wire-wrapped IC sockets on up, and testing them under the night sky. Small errors in alighment will add up. So, if you want the most accurate pointing, follow these tips that are NOT in the manual:1. Level the tripod as accurately as possible. You must do this FIRST. Every alighment option, with possibly the exception of the two-star alignments, requires a level tripod to work correctly. That's why the tripod includes its own little level, and the instructions do mention that you need to level the mount. I don't trust that little built in thing though. I use a six inch level that I place on top of the tripod, before I put the one-armed fork there. My level is placed in line with each leg in turn, and that leg adjusted until level, before moving onto the next leg. If you have some OCD like me, go around and do it again, just to be sure. Once the tripod is level, then the rest of the mount and telescope can be put together.2. Enter in Latitude, Longitude, Date, and Time, as accurately as possible. If you have a smart phone, get a GPS app and use it. I eventually got the Celestron SkySync accessory to do this part for me. (However, you still need to double check and make sure the Time Zone and Daylight Savings settings are correct with the SkySync. The instructons don't tell you that.)3. Use a lighted Reticle Eyepiece to center your alignment stars/planets. Don't use the Sun or Moon if you have an option, as it's very difficult to know where the exact center of those objects are in the eyepiece. A double crosshairs reticle eyepiece lit with a variably dimmed LED works great for this.4. Keep your chosen alignment objects far apart, and at least 20 degrees above the horizon. I don't know how well the NexStar+ handles refraction corrections, but to do it right requires both temperature and pressure/elevation data. Nexstar doesn't ask for these values, and I doubt the system includes the sensors to measure the quantities directly.One final recomendation: Get an alternate power source to suppliment the eight AA batteries that need to be placed in the half fork arm mount. You still need the AA batteries, as I discovered when I attempted to get by with just a PowerTank attached. Any glitch in the power cord connection to the mount will reset the Nexstar controller, and you will find yourself staring at the intialization prompt again. So, keep the AA batteries. Just suppliment them with either an AC adapter or PowerTank gel cell battery. Otherwise the AA batteries used alone will go dead within that observing session. (I've heard they will drain in as little as 30 minutes. I didn't push it to prove that.) I recommend the PowerTank battery accessory, since you can't always guarantee that an AC power source will be reachable from where you place the telescope. For me, I'm always tripping over cords in the dark. So any long power cord to an outlet that I can get rid of, I will. I place my PowerTank directly below the tripod tray on the SLT tripod mount. That keeps the power cable to the mount away from my toes.There are cheaper telescopes out there, but for ease of use, I just can't think of a better alternative than this 127 SLT NexStar+ system.At least I'm out with it regularly, and have been for over six months now. My old Newtonian never saw this much usage.

To begin, the photos are shaky and blurry because I shot them by trying to stick my phone close to the eyepiece, they do not do this scope justice, it is fantastic! I had very limited experience with telescopes, but the 127 SLT has blown away my expectations. I have seen the Orion's Nebula, rings of Saturn, bands of Jupiter and the 4 Galilean moons clearly. Various star clusters and a couple galaxies. Once you understand the setup and the must have upgrades you'll be ready to go.Pros: The scope is easy to assemble. The red dot is perfectly fine for what it is and gets you close enough. The 5" lens is more than enough to see the usual objects (moon, Saturn, Jupiter, and other Solar System Bodies). The first time i found the Andromeda Galaxy i was a bit disappointed as it just looked like a yellowish smudge in the sky, cool nonetheless. Then I observed Orion's Nebula and couldn't believe how good this little scope does, granted the tripod leaves much to be desired (but there are cheap work arounds, I'll explain in the cons. It's portable if you buy the right case which is great to get out of the city light pollution or to take camping. The tracking and auto alignments are great. Always perform the 2 star alignment as the 3 star align fails 9 out of 10 times, but 2 star is very good. Once 2 star is aligned you can activate tracking and the scope keeps the object you're viewing within frame or very close over a period of time, and you can let the computer drive you to your next object. It's super useful on cold nights and to not have to constantly correct where you're looking.Cons: the mount/tripod is not great, but I've mitigated vibrations and instability by buying cheap anti vibration pads on Amazon $20 and by loading a sandbag with 10lb weight and placing it on the plate of the tripod and this makes it 100 times better. This will be something I upgrade eventually for my own purpose, but I have no problems now and have no need to upgrade after the pads and sandbag trick. The standard pieces you'll want to replace and buy better one's, these pieces are always cheap that come with the scope, but I still use the 32mm for initially locating the object I'm looking for. You'll want something around a 25-32mm, 15mm, and a 9mm , and a 2x Barlow, this is all you need and you will be able to push your scope to its limits and on good nights with low atmospheric interference push a little past them. Further, i cannot say much on battery longevity in the scope as I immediately bought a cheap $8 adapter and used an extension cord for power until I bought the celestron mobile power supply for when I take it on the go. Overall, i wouldn't have changed my mind, this purchase was perfect, the tube didn't need alignment, the motors haven't messed up on me and i have nothing negative to say about this purchase.Recommended: buy the power supply, it's a game changer. Also, get the anti vibration pads and some way to weigh the tripod down, this makes a world of difference. Upgrade your eye pieces, you don't need anything crazy expensive, and buy a case to store your tube, tripod, and accessories, it makes storage and moving it a breeze. There are other well written reviews, so take your time and review what you need before buying. As my first telescope as an adult I'd rate this 9/10 for price and the ease of use and accessories built into the computer of the mount. Next scope will be a 10" lens with a solid equatorial mount base as i have no place for a Dobsonian in my current living situation. Good luck and clear skies!