Amazon.com: Customer reviews: Celestron - NexStar 127SLT Computerized Telescope - Compact and Portable - Maksutov-Cassegrain Optical Design - SkyAlign Technology - Computerized Hand Control

Nexstar 127SLT Mak is an affordable great telescope system, with proper handling

Reviewed in the United States on September 27, 2017

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

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.

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Iñigo de Oña

First Light on Celstron NexStar 127SLT MAK

Reviewed in the United States on May 21, 2013

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

In my opinion, this is an excellent beginner/intermediate or advanced grab and go scope providing crisp images, ease of use and many desirable software capabilities. I recommend it.

My training is in the physical sciences but not specializing in Astronomy or Astrophysics. I have always had interest in the stars from childhood and from having been a navigator in a destroyer during my naval service where I used them to navigate by. Several years ago when I retired I purchased two 1960s vintage equatorial mount 60mm refractors at garage sales and I have been using them while I did some research and reading to decide on the best next telescope to purchase.

I decided on a Maksutov-Cassegrain due its reputation for crisp, clear images and on Celestron NexStar for its quality reputation and the features of its GoTo/tracking software program. The deciding factor was that it was on sale at a large discount. I did consider Meade and Orion scopes before deciding on this particular Mak.

This year (2013) I took some of my tax refund dollars and purchased the Celestron NexStar 127 SLT Mak and also purchased some of what I consider to be essential accessories.

The purchase price of the tube and mount are only part of the price for a complete capable system. Beyond the sock items provided in the initial package, you will need lenses, filters, adapters, etc to fully exploit the capabilities of the mount, software and optics. In other words, to see the most, coolest stuff. By the time I have purchased all of the essential accessories to do this, they will cost almost as much as the telescope itself.

I have used the telescope every clear night for the last several weeks and I am very pleased. The NexStar program and alignment are easy to use and provide a better that ballpark result when going to an object. I did purchase the GPS unit, the Celestron accessory kit with additional lenses and filters, the house current and car battery power adapter chords, the USB interface cord, and the light pollution and oxygen filters. I live in the Phoenix suburb of Glendale so light pollution is a factor. The filters help.

So far everything works beautifully. My only two complaints are not vital but more nuisance

-that the GPS can take some time to synch -- be patient, I was not and had some self inflicted difficulties the first time I used the Mak.

-the tripod can be a little wobbly.

I will eventually get a heavier tripod, the GPS is what it is. I will try adding some five or ten pound weights to the tripod to see if that stabilizes it sufficiently.

I am not done with accessories.

Next on my list is a hard case for the tube and a canvass bag for the tripod and accessories so I can safely carry the system to the dark sky sites and star parties. I do want to try some web cam photography of solar system objects so a webcam purchase is in the future. Further down the road, I will get a digital camera adapter, a collimation lens and some higher quality viewing lenses and perhaps a dielectric diagonal.

Though I want to eventually get a large GoTo Dobsonian and I always lust after a nice, large Apochromatic telescope with a solid EQ mount for astrophotography,for now I am very happy with my NexStar 127 SLT Mak.

I will update as I do new things with the Mak or as I learn new things that may be of interest to buyers.

May your skies be clear and dark.

Iñigo de Oña
Nome de plume

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Jody Wilson

Christmas gift for wife. Great buy!

Reviewed in the United States on March 1, 2024

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

It’s perfect for our use. Not too big and not too small. I personally would like to have a large telescope with a larger field of view. This one works very well and tracks well. It’s not perfectly accurate at alignment but I haven’t tried to do the 3 star alignment either. You can just barely see the rings of Jupiter with it. And slightly see rings on Saturn. Great for my wife since she loves viewing the moon. I did replace the finder scope. A definitely needed upgrade! Other than that. No issues. The batteries are actually holding up better than expected. The tripod has been acceptable and doesn’t bother me at all. The focus is touchy but there are hacks for the shaking. The clothes pin is cheap and easy. Good buy for the price.

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R.T.

For Mak Lovers

Reviewed in the United States on December 9, 2023

Style: 90 SLT MaksutovSet: Telescope OnlyVerified Purchase

I have a love for Maksutov-Cassegrain telescopes. Started with an 80mm x 500mm f/6.3 MTO 3M-6A. Moved up to a C90 Mak. Wanted a go-to so I traded laterally to this NexStar 90 SLT. Same 90mm x 1250mm f/13.9 as the C90.
Maksutov pros: portability, planetary use, no collimation, meniscus corrector design
Maksutov cons: not as "fast" and limited deep sky compared to refractors, long cooldown time
90 SLT pros: features to price ratio, easy connection for DSLR/Mirrorless with a T-Ring adapter
90 SLT cons: Sky-Align proving fussy
I tried 3-star alignment on two occasions. Once from a Bortle 4 and once from a Bortle 3. Neither time would the scope "go to" Saturn after alignment. I'm sure it's operator error and I have to practice more. Went out in the field once and discovered Solar tracking not straightforward to unlock. I watched a tutorial and took notes so I'm sure the second time will be a success. (UPDATE: Solar Tracking successfully unlocked and working. YAY!)
This telescope is PERFECT for APS-C cameras vs The Moon or The Sun (NEVER AIM YOUR TELESCOPE OR CAMERA AT THE SUN WITHOUT A SOLAR FILTER FOR THE PROTECTION OF YOUR EYES AND EQUIPMENT)
With a level and balanced setup, Lunar tracking has been a breeze. As I said any other failures are likely on my part for planetary and solar go-to and tracking. Practice makes perfect. I'm still learning the NexStar system. I wish to expand my skills and get to Venus, Jupiter, Saturn and appropriate deep sky objects. This is a package I can definitely grow into.
Attached pictures taken with the Celestron NexStar 90 SLT and a Sony a6300 APS-C Mirrorless camera. No images were stacked, these are single frame:
Waxing Crescent final edit from ARW file
Abstract Image final edit from ARW file (tracked the Moon and it went behind a tree - took unfocused shot to show the donut shaped bokeh of the reflex lens)
3x eyepiece projections onto a6300 sensor of Moon Details final edit from ARW file
Solar image final edit from ARW file (I used a Spectrum Telescope Glass Solar Filter ST425G)
(UPDATE: Solar closeup image - final edit from 12 ARW files, aligned & stacked)
I also attached a chart showing how much of the sensor on APS-C is covered by the Moon. It would be the same coverage for the Sun as well.
If Lunar and Solar observation/imaging is a primary focus for choosing a scope, the 90 SLT is a great choice. It is less of a "tight fit" to get the Moon or Sun onto an APS-C sensor than the 127 SLT to ensure you are imaging in the clearest part of the lens (the middle). Also, there is more weight left over to add camera/accessories onto the 90 SLT and not overburden the 8lb payload capacity of the mount vs the 127 SLT.
Bonus feature for me: I plan on adding a small (perhaps 90mm x 500mm) achromatic refractor to my arsenal sometime in the future and the mount should be able to handle that well.

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Dy

Great for the price

Reviewed in the United States on February 21, 2024

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

I got this as a companion to my 6" dob and 100 APO SW's. And just wanted to see what a Mak had to offer. Didn't want collimation either. I have not tried the alignment function, because I'm basically using it for planetary/moon viewing now. When it's warmer I'll do that, but for now I'm just manually tracking, which isn't that hard. I actually like the handset vs. the smart phone I use with the GoTo on the SW scopes. The view is amazing, right up there with my 100 APO, maybe a bit darker and not quite as crisp, but not by much. I do want to say that with all the reviews I read, not one mentioned the cheap star diagonal. There is no brass(or any other) compression ring! I have a lot of spendy eye pieces, and even though I rarely tighten, I had to order a star diagonal with a compression ring. Not a huge thing, but together with the flimsy tripod, it's something to keep in mind. I combat the jiggle with a sandbag in the tray and some damper pads for the feet and it does just fine. All in all, for this price, even if I don't use the computer features, it's a very good buy. Update: Finally got around to using the computer features - pretty darn good. Very easy to align. Set it up before going to bed and 6 hours later it was still tracking the moon with only a slight adjustment to center in the eyepiece. Hopped right over to another star, back around, etc and it's still tracking very well. I upped it to 5 stars because it really can't get any better. The 2 items are negligible for this price. Update: tracking is fine - it keeps my city, but that's about it. Have to align each time but that doesn't take long. Again, for the price.....can't complain.

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Jon Groubert

Great optics, but the motor isn't so hot - AND THE WARRANTY SERVICE SUCKS

Reviewed in the United States on November 27, 2014

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

EDIT - I've lowered the rating on this scope. Not because of the optics, but because of the mount and Celestron's laughable warranty and awful customer service.

I originally bought this scope in November 2014. Within 3 weeks, the mount failed, which I describe below. Amazon's 30-day return policy was still in effect, and they were champs. Amazon sent out a second, brand new scope which I got in 2 days. They sent it out to me even before I sent back the old one. 7 months later, the mount failed again - in exactly the same way. Since Amazon's 30 days was long over, that meant I had to deal with getting the mount repaired under Celestron's 2-year warranty.

Suffice it to say that Celestron's warranty isn't worth the paper it's written on. Celestron customer service lies to you at every opportunity, saying "Oh, that 30-day turnaround period in the warranty is 30 working days, even though the warranty clearly doesn't say that at all, and legally, of course, our not saying that is binding upon us," and then saying, "Oh, your mount already shipped out. Oh, I mean, your mount has been repaired and is at our shipping desk, ready to be shipped out. Oh, I mean, we haven't started working on your mount. Oh, I mean, we can't find your mount." They literally told me all of these things, and in that order,. It took over two months of emailing, telephoning, and just generally beating my head against the wall until I got my mount back with the clutches tightened. I have never encountered worse customer service.

Because of that, I have lowered the rating for the scope. The optics are just as terrific as I described below. But not only two mount failures, but lying, deceitful, dishonest customer service means that the rating has gotta be lower. Oh, they returned the scope to me - after just over TWO MONTHS, not the promised 30 days. I thought about giving this just two stars, but that would imply that the optics of the scope were bad, which they're not. - END EDIT

ORIGINAL REVIEW - I've had the scope for just over three weeks now, and have had it out about ten times. Or I should say, I've had "them" out, because this is my second of the same scope. The first one had to be returned because of a bad motor or handset.

Let me start off by saying that the optics on this scope are absolutely superb; more on that later. Let me also say that Amazon's return policy is great; couldn't be smoother. They sent me out a second scope even before I returned the first one. I was only without a scope for three days until the new one got here. That's not the problem.

The problem was the motor failure on the first scope. It happened while I was observing, with the motor engaged, right after I took an eyepiece out. As I lifted it, the eyepiece got caught by the setscrew in the diagonal, and was stuck there for a second. In that second, because the eyepiece was stuck, I lifted the back end of the scope up about 5 degrees or so. Immediately after this, the azimuth motor (left and right) developed an incredible delay - even though I had moved the scope in altitude (up and down). The delay was such that it would take 11 seconds for the telescope to move in azimuth after I pressed the button.

I literally had time to be looking through the eyepiece while I was pressing the button, then time to remove my eye from the eyepiece, more time to look at the hand controller, and confirm both that I was pressing the correct button, and that the hand controller was registering the press (a little number appears in the upper right corner when you press, indicating the motor speed), and had time to return my eye to the eyepiece, all without the telescope moving at all. 11 seconds, every time I pressed, left or right. Obviously, the telescope had responded almost instantaneously before this. This is a big problem, because of two things - it becomes very difficult to move the scope, and the goto function was shot - it was not finding objects any more.

This was not a function of temperature - I had had the scope out in subfreezing temperatures, and this did not happen. This also continued to happen once the telescope warmed back up inside.

This was not a function of a bad power supply. I had both fresh batteries installed, and a freshly recharged 12V Lithium ion pack attached.

It also wasn't a backlash problem. I went through the backlash settings and nothing changed.

I've asked around, and no, it does not make logical sense that my pull in altitude would cause a problem in azimuth. But the timing still says to me that this was the cause of the motor failure. AND THAT SHOULDN'T HAPPEN. The motor should be a lot more robust than that.

Like I said, now I have a new scope. I've had it out, and it's just fine. Everything is as it was.

As you probably know, this is a computerized goto scope. That means that it is motorized, and there is a hand controller with a readout where you can tell the scope what you want to see by pressing some buttons. The whole procedure is very easy to learn, very easy to do, and after only a couple of observing sessions, is completely intuitive. The goto finding feature is also very accurate.

Now for the optics. They are beautiful. The scope puts up great sharp images. You feel like you're orbiting the moon. I even used my 4mm Plossl on the moon and got it up to 385x and it was still plenty detailed - although the focus was soft, because that is simply too much magnification for this size scope. Star clusters are nice and sharp. I could see detail in the Orion Nebula from my rooftop in Manhattan. MANHATTAN!!! THE LIGHT POLLUTION CAPITAL OF THE WORLD! Jupiter is still too low in the sky right now, but next month when it's higher, I'll take a look and report back.

EDIT 12/19/14 - I've had the scope out to look at Jupiter now that it's much higher in the sky, and it is gorgeous. The two main equatorial bands are quite distinct and show some detail. Not only that, but the other night I saw the transit of the shadow of Europa across the face of Jupiter. You have to use a lot of power to see it - the 9mm eyepiece that comes with the scope, or even higher, if you've got it - but it was there, a tiny little black dot, moving along. Wow. Just wow.

Other reviews state that the eyepieces that come with it are not as good as they could be. This is true, but it is an unfair criticism and therefore irrelevant. This is the way of things with all telescopes - the supplied eyepieces are okay/fine, but not great. Any telescope you buy is going to come with just okay/fine eyepieces. You should therefore leave yourself a budget of an additional $165 for upgrades, both for additional eyepieces, and for other accessories, which I discuss below.

There have been complaints about the mount not being stiff enough or robust enough to make vibrations tamp down quickly. This may be true. I haven't really had much of a problem here, but it can be dealt with by 1) tightening all the tripod screws about a quarter turn each (don't over tighten, or you could crack the plastic!), 2) tying some weight off of the bottom of the connecting rods that hold the accessory tray, and 3) putting the mount on anti-vibration pads. These simple steps will make the mount much more stable - if you even have this problem. I don't.

Admittedly, this motorized scope goes through regular batteries very quickly. And you cannot use regular rechargeables on this scope, because they are rated at 1.2v, not 1.5v that regular alkalines have, and therefore provide insufficient voltage. (8 x 1.2v each = 9.6 volts, instead of 12.) You should get a rechargeable 12V battery pack instead.

With all that in mind, here is a list of things you may need to buy for that $165 extra dollars. Remember, however, that you don't absolutely NEED any of these things - the scope will work just fine without any of them. These things will make the scope better.

1. A 12V Lithium ion battery pack. Amazon sells a nice one for $21.95 here:

http://www.amazon.com/Portable-4500mAh-Rechargeable-Battery-Wireless/dp/B008UKKXRC/ref=pd_bia_nav_t_1?ie=UTF8&refRID=03G4P0GKEJ972N3G6P79

2. A 32mm Plossl. The scope comes with a 25mm eyepiece, which again, is just fine. However, the 25mm doesn't provide the widest possible field of view possible in the scope, and you will want that. While the Goto function can be extremely accurate, placing what you want to see right in the middle of the field of the 25mm, on some nights it's better than others, which I believe has to do with how well you have levelled the scope on the surface from which you're observing. (The scope has a spirit bubble level built into the mount to make this very easy to do.) The 32mm has a wider field than the 25mm, so that your chances of landing on target are greater with the 32. Any 32mm Plossl will do; Amazon sells a nice one for $39.95 here:

http://www.amazon.com/GSO-1-25-Plossl-Eyepiece-GSP-32/dp/B006I0IWQU/ref=sr_1_9?s=photo&ie=UTF8&qid=1417061856&sr=1-9&keywords=32mm+plossl

3. A dew shield. Here in Manhattan, I have not had any dew accumulating on the front lens (called the meniscus) of this scope, probably because there isn't much grass and plant life around, and probably also because I'm observing from the roof of my apartment building. However, if you're observing from just about anywhere else, you probably will have this problem. A dew shield is a tube that extends off of the front of your scope that helps prevent this from occurring. Amazon sells one of these (which I cannot vouch for either in terms of fitting the scope or quality - you'll need to do your own homework on this) for $36.50, but you can find it cheaper elsewhere, or you can make one yourself:

http://www.amazon.com/AstroZap-Flexible-Telescope-Shields-Celestron/dp/B003VPYJRG/ref=sr_1_23?s=photo&ie=UTF8&qid=1417062055&sr=1-23&keywords=dew+shield

4. You might want to upgrade from the red dot finder that comes with the scope. There are a few problems with the red dot finder that comes with the scope: 1) it doesn't magnify the image, so the accuracy in alignment is limited, 2) you can't see any more stars with it than you can see with your own eyes, and 3) they are hard on the neck/back/knees, because you have to crouch down and contort yourself behind the scope to look through it. Instead, you could get a "right-angle correct image" (RACI) finderscope. Of course, Amazon sells these; here's a good one for $67:

http://www.amazon.com/Right-Finderscope-Bracket-High-Point/dp/B006GTC9Y4/ref=sr_1_2?s=electronics&ie=UTF8&qid=1417062318&sr=1-2&keywords=finderscope

These upgrades come to $165. Like I said, however, these aren't immediately necessary to enjoy the scope. You can work up to these slowly. Take the scope out a few times, see if you really need to get these things before diving in.

All in all, even with the motor problem, this is still a terrific scope because the optics of the Maksutov design are excellent. I would heartily recommend this scope to anyone who asked.

If you have any questions about anything I've written, please feel free to ask me a question in the comments selection. Enjoy!

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R. ODonnell

The red dot finder works like a charm

Reviewed in the United States on February 19, 2024

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

After an easy assembly process, I followed the instructions to set up the red dot finder. Do it in the daytime. It is so much easier. At night alignment with 3 stars went smoothly because I lined up the red dot on each star and there they were in the eyepiece every time. Right now there are only two solar system items to see unless I'm out on the deck at 1:30am. The moon is gorgeous with this scope and depending on the power of the eyepiece used it can either fill the view or show me super close ups. Jupiter is right near the moon for several days and I was able to see bands and four moons. Strangely, the moons are brighter than the planet itself. I used a 25mm eyepiece with a 3x Barlow (<--the Barlow is purchased separately).

I do wish the tripod was a bit taller (I'm 6'1") as I had to kneel on the ground and crane my neck to look through the red dot finder. Once I see the dot all I have to do is run the motors until the dot covers the target. After alignment with 3 stars, the scope went right to the moon and Jupiter. You need to realign each time you move the scope to a different location. After a little practice, this is gets easier to do. I felt the tripod was fairly strong - on par with several $100 photo tripods I've used.

This will eat AA batteries if you're out for a few hours and looking at a lot of different things. I use a TigFox portable power station with a $10 AC adapter and I could run for several days.

There is a tracking mode on the handheld, but I can't see that it tracks anything. I may not be setting it up correctly as there are a few options. I chose the alt-azimuth option as that is the type of mount on this scope.

Now, about customer service. The 25mm eyepiece included with the scope had something smeared on the inside of the lens making it blurry. I contacted CS on the Celestron website, explained the issue and they got back to me in two days asking for a photo of the eyepiece, name, address, and Amazon order invoice. Two more days and they had shipped a replacement at no charge. They were very courteous and professional.

I love this scope (not as much as my wife! Yeah, she was looking over my shoulder) and couldn't be more pleased. Now I need to cut down a bunch of pine trees around my deck.

Recommended, especially since there is a $50 coupon available on Amazon at this moment.

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Pat

short life, lousy build quality and tech support not available with reasonable effort.

Reviewed in the United States on October 31, 2022

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

*Update- I got a call back from Tech Support- The person couldn't hear me because they were using a speakerphone with a child crying in the background! Then they hung up. Super impressive all the way around.

I bought this in mid-July and now by the end of October the mount is dead. Puts 'No response' error on the handset. I spent an entire evening winnowing through the 'help' files on the Celestron site. Filled with gems like "maybe the cables inside are loose". Ok, I've been a technician for the past 40 yrs, so I open it up. Nothing loose (but really poor build quality. On the one board the male connectors are too far back on the board to let the cable seat fully/properly).

Next up- "maybe the handset needs to have it's firmware updated". Find a pdf on their site explaining that process... of course it really doesn't work quite the way described but finally manage to get the handset into the 'boot loader' screen and update the firmware. Momentarily it looked like success, but nope, another minute or so and right back to the error. Is it the handset, or the mount? Who could say. Look at the warranty- 2yrs, but you pay shipping and insurance both ways. That has to be a significant amount of the cost of the mount.

So, still hoping someone there could give me something useful I call tech support. Now here's a shock- they are experiencing higher than average call volumes both time I tried to call. (when was the last time they weren't? Maybe they need to be taught how to calculate 'average'). I sat on hold for an hour this last attempt and never did reach a person.

I guess I'll be making or buying another mount for the scope so that I can put it to use. But I certainly won't buy anything else from Celestron and would not recommend the product to anyone.

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Matthew Fields

Clever idea, poorly implemented.

Reviewed in the United States on July 12, 2011

Verified Purchase

November, 2012: After owning this product for 18 months, I am downgrading it.

The optics of this scope are pretty good. And the idea of an alt-az tracking mount with go-to features is sound. But the kit as actually delivered is problematic. If my experience is any indication, about half of the time, the kit will be out of commission due to failure of critical components.

As I noted in my original review, the Finderscope failed shortly after I got the kit, making the scope extremely difficult to aim and steer, and impossible to align for purposes of the tracking feature.

Since then, the Altitude motor has failed twice, and the plastic bracing of the tripod split clear through--fortunately NOT while it was holding the scope tube. Each of these situations has meant 2-1/2 months of the kit being out of commission while I begged Celestron for a return materials authorization number, shipped the materials to Celestron, waited for Celestron to check the parts in, and then waited 6 weeks for them to service or repair the parts.

The root cause is apparently low-quality materials, including cheap Chinese motors.

Celestron sells the SLT mount, hand-controller, and tripod as a kit without any optics for about $350. I recommend steering clear of that kit and any kit containing a tripod or mount made by Celestron, including their much-ballyhooed self-aligning SkyProdigy mounts, which, in their photos, appear to be made from the same underlying components.

At this point I am more seriously looking at products from Orion and Meade to replace the unreliable components from Celestron.

However, when the product actually works, it works fairly well, as I explained in my original review of this product from over a year ago, which follows below.--------------------------------

Disclaimer: I'm a rank beginner, and this is my first telescope.

Intermediate and advanced scope owners tend to recommend a larger Dobsonian scope (eg Orion 6- or 8-inch) without motors, as the way to get a lot of optics at a low price. But knowing that I was going to struggle to find anything fainter than Saturn, I shopped for something smaller and lighter that I'd be more likely to use, with tracking so once I found something, I could show it to somebody else. Tracking was important to me because the Earth's rotation can otherwise make something drift out of the field of vision in just a few seconds.

A telescope can basically be mounted two ways: Alt-Az and Equatorial. An Alt-Az mount has two degrees of freedom: Altitude (angle from nadir to zenith) and Azimuth (compass point). An equatorial mount can be pictured as the same two degrees of freedom tilted up so that zenith is replaced with the north (or south) pole, altitude is replaced with latitude, and azimuth is replaced with longitude. On an equatorial mount, tracking is just counter-rotating once every 24 hours on the longitude axis while doing nothing on the other axis, so a clock mechanism is all that's needed. Tracking is more complex on an Alt-Az mount, so a computer is needed. But physically, equatorial mounts are a bit more elaborate and thus expensive because the tilt towards north creates balance considerations that alt-az mounts don't experience.

So the upshot is that a budget alt-az mount that can do tracking is likely to have a computer. So, why not have a Go-To database with it? The database on this system has only about 4000 objects in it--but for somebody like me, that's plenty, besides which larger Go-To databases tend to contain tens of thousands of things that are too faint to see in a 127mm scope. I find the Go-To feature a blessing, showing me a bunch of things I wouldn't have been able to find by myself, and describing them in short encyclopedia entries that scroll across the hand-controller's display.

The system ships in one big box, which is a bit awkward for handling. I used the internal box and bubble wrap plus some foam rubber of my own to fit the scope tube into a wheeled backpack, with tray, eyepieces, diagonal, finderscope, hand-controller, and accessory tray in their original containers or bubble wrap in side pockets; a separate wheeled duffel proved perfect for the fork arm, tripod, and a red-LED flashlight that I purchased separately. That made the whole system quite tolerably portable.

The enclosed red-dot finderscope died after a little bit of use, apparently because internal wires got torn by the finderscope-alignment process. Celestron replaced it, and the replacement appears to have a sheet of plastic protecting the wires. Without a finderscope (a low- or no-magnification tool that you use like a gun sight), it's very difficult to aim a telescope at anything, so the scope was essentially crippled for everything except lunar observation until the replacement came--and aiming at the moon was a bit of a struggle. A little QA problem, but kudos for their customer-service.

This is a Maksutov-Cassegrain scope, which should not need collimation, but it arrived slightly out of alignment. The primary mirror can be aligned
to the secondary with careful use of 2mm and 3mm allen wrenches (not supplied), and I recommend a pinhole cap (not supplied) for the procedure. Faint stars should turn into symmetrical doughnuts when slightly unfocused. I find that having done this once, the scope holds its collimation well.

The set-up instructions worked for me the first time, and about 30 minutes into my first night, I was looking at Saturn. I recommend reading the instructions carefully to get the best results from three-star or two-star alignment (the latter requires that you be able to identify the two stars). For each star, you'll first align it in the finderscope, press "enter", then center it in the eyepiece, before pressing "align". The mount wants the last moves to be up and right, so it can take into account the play in the motor gears, else when you ask it to find things, they may be off-center or slightly outside the field of vision. The computer has a database of cities from which it can estimate your position on Earth; that combined with the current time from a cell phone is generally accurate enough to orient it. But if you're taking it to a remote field, you might want to look up the latitude and longitude ahead of time.

And a remote field is a wise idea--the darker, the better. Telescopes do magnify, but their main purpose is to collect light--to show you things too faint to see otherwise. City haze and nearby light can interfere with that. Still, even in a city, this scope easily shows Saturn and Jupiter with some detail, craters on the Moon, double stars, and some star clusters. Darker skies are needed if you want to try to see nebulae, remote galaxies, and other faint objects.

The included diagonal--a mirror creating a 90-degree joint--makes the scope more comfortable to use and gets the image right-side-up, though it is in mirror image. If you're viewing fainter objects and can deal with an upside-down-and-backwards image and a little awkwardness, you can put the eyepiece directly on the scope tube to eliminate the light-loss from the diagonal. Doing so shortens the tube substantially, so you'll have to re-focus.

A minor design flaw in the fork arm is that the hand controller (and optional external power) plug into the rotating part of the base rather than the stationary part. The computer compensates for that with a "cordwrap" feature that remembers how far the arm has rotated, so that when you ask it to show you an object, it may make a just-under-360-degree rotation in the opposite direction to avoid getting making a mess of the wires.

Motor speeds vary from tracking speed to 9 faster speeds arranged in powers of 2, so the fastest speed, [ (2^9) * tracking speed ], is about 3 degrees per second. That's a lot slower than you can tilt it by hand, but moving the scope by hand makes it lose its alignment, unlike the active-passive sensor systems on some more expensive systems. I haven't found this to be a problem.

8 AA alkaline batteries in the fork arm power the system, and are good for many hours of use--Celestron says about 3 hours, but I used my first set for about 9 hours over several nights before they unceremoniously died. Celestron doesn't recommend rechargeable NiCads, claiming they don't produce a high enough voltage to even start the system. A 12V center-positive external power supply can be used, and Celestron and other vendors offer a longer-life rechargeable battery system just for that purpose.

When I've used this at fairly dark locations, I've been able to see quite a bit of detail. The optics seem very nice.

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R. Allen

Best bang for the buck!

Reviewed in the United States on April 16, 2014

Style: 127 SLT MaksutovSet: Telescope OnlyVerified Purchase

Ok, I looked long and hard for a telescope and I have to say this is the most bang for the buck considering limited monetary funds. One thing I suggest getting is a lense kit when you do buy this. I got the Celestron lens kit, but Orion has a kit as well and it comes with a 40mm lens, which makes for a wider field of view. I have not tried doing the three star or two star alignment. I just used the solar alignment because I am more interested about looking at the planets, the moon and the Sun in our Solar System.

If you want a scope for Nebulas and to take pictures of them, don't get this scope. The aperature is 5 inches with a long focal range; however think about this. If you go from a 5 inch aperature to a 6 inch aperature, it will cost you about 200 to 300 dollars more.

I think this a good beginner scope because of the "Go To" capability. You don't need to know that much about the stary sky to find Jupiter, Saturn, Mars, Venus or Mercury. Just find out where they are in the sky, point to it, use the solar alignment and the scope follows whatever you have programmed it to follow. The scope gives clear images of whatever you have pointed at. I am think about getting a 3x barlow for the scope. I used a 2x barlow on this scope with a 32mm lens and the image is great, so I wonder how a 3x barlow would be.

The scope comes with a variety of different software for use on the computer. I think you can hook the telescope up to a laptop and control it from the computer with the provided software. This telescope does not come with imaging software; however I think when you buy a camera specifically for a telescope, the camera comes with the software. Also this scope comes with a "Lite" version of SkyX software. For SkyX, you can input your location and it will give a map of the sky showing where objects are in the sky compared to your location to make planets easy to locate. If you wanna control the telescope with SkyX, you have to buy an upgrade from the website. This version does not allow for control of the telescope.

The only cons are that you have to buy a lot of accessories for this scope. Two cables that go together just to hook it up to a laptop,(to update the motor and hand control software). If you want to run it on AC power you gotta buy an adapter, plus if you take this out in the middle of nowhere, you need to a get a battery pack for it and a I suggest the 12v car adapter, so that way it does not draw as much power as a 120v adapter. Note: You don't have to buy Celestron's battery pack, any generic one you get at a deparment or auto store will work as long as it has the car adapter outlet. I have not tried using it on batteries. I have heard that the batteries will only last one night, so getting rechargeable batteries would be the best best over regular batteries.

All in all a very good scope for the money. The focal length is long which means a more powerful scope, but the field of view is smaller. Good buy.

One thing I will add. I have not tried to look at nebulas or distance stars with this telescope. I want to see the sun(must use a solar filter, do not look at the sun with this telescope or any telescope without one) and the planets. I have not used the sky align with it, just the solar system align. Basically, align the telescope with the planet you wanna see and the press align. The scope will track, but you might have to realign every 10 minutes or so. Also if you look at the moon with this telescope or any telescope, use a moon filter; otherwise you will see spots on your eyes for a while.

Oh it does shake a little when it is windy out. Also when you try to focus using a powerfull eyepiece, the image shakes a lot. The viewfinder is good. May have to make minor corrections every once and a while. The control pad takes a lot to get used too. Not user friendly but works.

The only thing I don't know about this scope, and it has to do with the tripod...is if I get a bigger aperature telescope, would it fit on the mount for this one.

Just ordered a solar filter for this scope. If anyone is looking for the right solar filter, go for Orion 07710 5.81 filter. It fits snuggly and you don't have to use any of the foam inserts for it, because it is already foamed lined.

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