In this Celestron NexStar 4SE telescope review, we are going to examine everything this versatile scope can deliver for the backyard astronomer, and any shortcomings it suffers from.
Each model is a compound scope (or, catadioptric), which cleverly combines mirrors and lenses to squeeze a long focal length into a short tube. The focal length of the NexStar 4SE is a whopping 52”, but this is squeezed into a 13.5” optical tube.
The 4SE is a Maksutov-Cassegrain design, whereas all the other members of the range are Schmidt-Cassegrain. This is a cheaper design that is generally used in smaller compound scopes.
You can expect to pay $500 to own this telescope (check today’s price – opens in a new tab). In the rest of this review, we’ll look at what you can expect of the NexStar 4SE and whether or not its cost represents good value for money.
What to Consider Before Buying the NexStar 4SE
Celestron’s big selling point for this model is the GoTo computer.
You can select from a database of 40,000 night sky objects. When you’ve picked a target, the motorized mount will slew the telescope around to point at the object you’ve chosen. Once in your eyepiece, the motor will track it as it moves across the sky so you don’t lose sight of it.
Theoretically, this is a great solution for the more casual backyard astronomer who is more interested in spending time outside seeing objects than finding them.
In reality, selling a 40,000 object database with a 4” telescope is, at best, misleading marketing.
Telescopes work by gathering light and the more light they collect, the more objects and details we can see. Unfortunately, the 4-inch aperture of this telescope is too small to reveal most of the objects in the database, especially under light-polluted skies.
In summary, this scope is for you if your interest is seeing details of the moon and planets and even double stars, which it splits well. Just don’t be misled by the huge database, this telescope is not great if your passion is hunting galaxies and nebulae.
In the next section, we’ll study this telescope in more detail, looking at all of its features and benefits.
Features and Benefits
In this section, we’ll look at the key areas of the telescope which you’ll need to consider to see if it’s the right one for you. They are:
- Build Quality
- Optical Performance
- Mount Performance
- Included Equipment
- Set-up & General Use
- What You Can See
The telescope is made of a plastic and metal body with large rubber grips on the focuser and ‘mirror flip’ control.
Behind the eyepiece holder is a built-in prism that turns light collected by the OTA (optical tube assembly) 90° into the angled viewfinder.
The mirror flip control moves this prism out of the way so light can travel straight to the T connector at the back of the scope. This is where you can attach a camera for astrophotography… but more on that later.
The 4SE is well constructed and tightly put together. It feels heavier than it looks which adds to the sense of professional construction.
The main mirror is a spherical design and the corrector lens has an aluminized spot on its rear. As is normal for a Maksutov telescope, this spot serves as the secondary mirror.
Celestron’s 4SE arrives perfectly collimated out of the box and will remain that way if treated well; users report perfect ‘airy discs’ when stars are properly focused.
Because the OTA is sealed at both ends, there are no dust issues inside the tube and so no need to worry about cleaning the primary mirror.
The long focal length and slow focal ratio, as we mentioned in the introduction, means that you’ll have higher magnifications and narrower fields of view for any given eyepiece when compared to a scope with a much shorter focal length.
This makes the scope great for bright, narrow-field work, such as viewing planets and double stars, but less so for dimmer, wide-field objects such as nebulae and star clusters.
Expect to need a larger eyepiece to get the best of wide views like the Pleiades, for example. You may have to invest in a wide-angle 32mm or even 40mm eyepiece to enjoy them.
We particularly liked the Celestron Luminos range which has an 82° apparent field of view and includes a 31mm eyepiece.
The mount is a single fork arm sat atop a sturdy steel tripod with 2” diameter legs.
Those big legs make it a reliable, unshaking platform for the small telescope atop.
The mount includes a simple built-in wedge setting so the scope can be used for astrophotography. It’s not as good as a standalone German Equatorial Mount but is a happy compromise.
As we’ll soon discover, the 4SE is not a great choice for night sky imaging but the video below shows you how to set it up.
As well as the OTA, motor drive and mount, Celestron include a red dot finderscope and 25mm ExCel Plössl eyepiece in the box, as well as software and connector lead that enables a PC to control the telescope’s GoTo motor.
We’re not big fans of the red dot finder, especially when you want to track down fainter objects, but they are intuitive and simple to set up for beginners.
The finder is largely unused on a motorized GoTo scope like this because the model is designed to find and track whatever you are looking for. You will, however, need to make sure the finderscope is properly aligned to help with set-up.
You’ll want to add to the single eyepiece that comes in the box – more on that shortly – but the included 25mm ExCel Plössl is good quality, as we found in our ExCel eyepieces review.
Set-up & General Use
The whole NexStar package is relatively small and comes in three parts.
The mount head weighs 7 lbs (3.2kg), and the tripod adds a further 10 lbs (4.5kg). The telescope itself weighs 6 lbs (2.7kg), so the whole setup comes in at 23 lbs or 10.4 kg.
This is an easy weight to move around but solid enough to give the needed stability. It’s also small enough to store without taking up much room.
Out of the box, the NexStar 4SE is well collimated and should not need adjusting if the OTA is treated well. Collimation for these scopes normally means a return to the manufacturer or professional retailer, so it is best to look after them.
On that note, it’s worth keeping the box the OTA arrives in as this makes for useful storage and a lot cheaper than a dedicated storage box.
The instructions are simple to follow, especially the quick setup and you can be operational within a short while of unpacking.
In the field at night, attaching the telescope onto the GoTo head can be a little tricky, but is far from an issue and gets easier with practice. It’s worth doing this in daylight, which will also give the scope time to cool down for optimum performance.
On the topic of cooling down, small Maksutov-Cassegrains like the 4SE are prone to dewing, so it’s worth ordering a dew shield to extend your viewing window.
The tracking motor is quiet and relatively fast and keeps hold of objects well, i.e. they stay centered in the eyepiece as you view them without needing to make manual adjustments.
There are nine tracking speeds you can employ, the fastest of which is 3° per second.
SkyAlign is the process of telling the telescope’s SkyScan controller where in the world you are and which way it is facing, this is essential for the goto functionality to work.
When setting your location, use your latitude and longitude rather than your zip code or town because this will provide better tracking accuracy.
Getting the scope aligned with the stars requires pointing it at 3 bright ones, and that’s it. This is a simple enough procedure, shown in the video below.
The biggest frustration is that you’ll need to set (or confirm, if you have a SkySync GPS module or SkyPortal Wifi) the time and date every time you use the scope because there is no battery-backed memory within it.
You can use 8xAA batteries to operate the motorized tracking, but they don’t last long and there are reports of erratic performance. Instead, you’ll need Celestron’s PowerTank or similar for reliable operation in the field, but it can be plugged in at home.
Just note that you should still keep batteries in the controller just in case the power supply fails, even momentarily, otherwise the controller reboots and you’ll need to set it up all over again.
Three-star alignment gives good, if not perfect results.
The objects you are looking for should appear in your eyepiece but may not be perfectly centered. It is possible to complete a more precise alignment by using the wedge, as shown in the video above under ‘Mount Performance’.
To get perfect centering without the wedge, first, slew to the object and then use the hand controller to fine-tune where the telescope is pointing. Tracking is very impressive and can hold an object centered for 15 minutes or more before a small adjustment is needed.
Some users report the tracking control struggles in the cold, meaning it moves slowly or the controller becomes temperamental, but this not a large scale experience.
Finally, remember to stay up to date with Celestron’s SkyScan software for the tracking controller, which is periodically improved.
What You Can See
Firstly, it’s worth noting that the design of the scope means you’ll see objects the right way up in your EP (eyepiece), unlike the inverted view of most compound scopes.
The 4SE’s best performance is saved for the planets and moon. As we’ve commented a couple of times, this scope is designed to excel with bright objects.
In terms of deep space objects, you can certainly see the brighter members. Andromeda Galaxy appears as the faint fuzzy you’d expect. It is nothing dramatic in this 4” scope but is pleasing nonetheless, as is the Orion nebula.
The 4SE performs very well with double stars, as we’d expect for the given specifications. Don’t be afraid to use shorter focal length eyepieces here to tease out tight separations with high magnification.
Stars generally are rendered clear and sharp with good color.
You’d be forgiven for thinking that a tracking scope was ideal for astrophotography, but that’s not necessarily so.
Unless you have a wedge and polar align this scope, its tracking is not accurate enough to use a camera on it for very long. Even the built-in wedge of the supplied mount does not do enough to make up for the lack of periodic error correction in the drive motor.
Besides, because the motor arm is only designed for a small scope, adding a heavy camera to your setup will throw the tracking out even faster.
Exposures of bright objects for a few seconds are fine, but holding your lens open for the time needed to capture faint nebulae is not feasible.
If you’re looking to take images of the night sky, stop reading here and instead see our Best Telescopes for Astrophotography.
Depending on what you’ve read so far, you’re either ready to take the plunge and buy a NexStar 4SE, or you’re thinking it’s not quite the right model for you.
If it’s the latter, let us suggest a couple of alternatives that could be a better fit:
- Bigger Aperture, Same Model: NexStar 5SE, 6SE and 8SE
These have mostly the same features and characteristics of the 4SE, but the bigger apertures reveal much more detail and let you delve into fainter deep sky objects.
But, they also cost a lot more!
- Bigger Aperture, Similar Price: Celestron NexStar 130SLT
This option costs about the same as the 4SE but gives you an extra inch of aperture and gathers 56% more light! You’ll see more detail and fainter objects (especially as its focal ratio of f/5 is more suited to deep space objects). It also has the same GoTo capabilities as the SE range.
However, you’ll be buying a Newtonian reflector instead of a compound scope. This is bulkier and will need collimating from time to time.
In the end, telescope purchase is always a matter of compromise!