Celestron NexStar 4se Review
- in depth Review of Features
Telescope Reviewed: Celestron NexStar 4se
- Powerful telescope in a small package
- Can automatically find and track objects as the earth spins and objects move across the sky
- Good grab and go scope because of its handy small size
- Easy to add a camera for astrophotography with a photo adapter—good scope for this purpose
- Corrector plate exposed to elements—might want to get a lens shade to protect it from excessive glare, dust and condensation
- Smaller aperture than the 6se means considerable less image brightness, which could limit observation of some more distant objects
The NexStar 4se is another in a successful line of computerized catadioptric telescopes from Celestron.
The NexStar 4se is the smallest of that line, but it still crams a lot of value into a small package.
It's a good telescope for beginners and experienced observers that have a little bit more money to spend. Finding and tracking objects across the sky is easy after quick and simple setup.
The 4se is a good grab and go scope for taking with you on trips, wherever you might be going. It's easy to transport and is reasonably light for a telescope of its kind with a computerized mount.
102 mm (4.02 in)
1325 mm (52 in)
Focal Length of Eyepiece 1
25 mm (0.98 in)
Magnification of Eyepiece 1
Single Fork Arm Altaximuth
8-AA batteries (not included)
Highest Useful Magnification
Lowest Useful Magnification
Limiting Stellar Magnitude
1.37 arc seconds
1.14 arc seconds
Light Gathering Power (Compared to human eye)
Apparent Field of View
Linear Field of View (@ 1000 yds)
53 ft (16 m)
Secondary Mirror Obstruction
1.38 in (35 mm)
Secondary Mirror Obstruction by Diameter
Secondary Mirror Obstruction by Area
As we've talked about before, Celestron's NexStar line of computerized telescopes all owe their design sensibility to one of the most popular telescopes of all time, the Celestron 8 SCT (often referred to as the "C8"). All of the NexStar telescopes are catadioptric telescopes with computerized alt-azimuth mounts that allow motorized tracking of objects.
The NexStar 4se is a Maksutov-Cassegrain telescope (referred to as a "Mak-Cass" for short) with a 1325 mm focal length and a 102 mm aperture (just over 4 inches). It provides pleasingly bright images with good crispness because of its fair sized aperture and StarBright XLT optical coatings. These coatings allow the 4se, like other telescopes in this line, to have high-fidelity light transmission to the viewer, thus conveying sharp, high-contrast images.
Maksutov-Cassegrain telescopes ("Mak-Cass" for short) are a type of telescope that use a catadioptric design, which means that they include elements of both reflector and refractor telescopes. That is, they use both mirrors and lenses to gather and focus light before it is transmitted to the eye of the viewer.
Mak-Cass telescopes fold light within the tube of the telescope with a series of mirrors, and hence are mostly reflector telescopes. However, in order to compensate for aberrations that might otherwise result from using mirrors alone, the Mak-Cass telescopes use a corrector lens. In the case of the Mak-Cass, the corrector lens is a meniscus.
By folding the light within the tube of the telescope, a Mak-Cass can have a much smaller tube than a comparable reflector telescope.
In Mak-Cass telescopes, light enters the tube through the meniscus corrector plate on the front of the telescope. It then strikes a primary concave mirror at the base of the telescope tube. From there, it is reflected onto a smaller secondary mirror on the back of the corrector.
The result of the optical configuration is a compact, easily portable telescope with excellent light-gathering capabilities. With a Maksutove-Cassegrain telescope, you can see the Moon and planets, as well as brighter deep-sky objects. The aperture, which is smaller than that of some of the other telescopes in this line, may have some limiting effect when it comes to viewing dimmer or more distant deep-sky objects, but the 4se is surprisingly effective for its size.
Additionally, the 4se comes with the same excellent 25 mm E-lux Plossl eyepiece that is also included with other telescopes in this line. This eyepiece can magnify up to 53x.
The NexStar 4se vs 6se: How Do They Compare?
A lot of people ask what the difference is between the Nextar 4se and the 6se.
In truth, these two telescopes are very similar. They have the same StarBright Optical Coatings for high-fidelity light transmission and sharp, high-contract images.
They both also hearken back to the great Celestron 8 SCT (the "C8"), which still holds a special place in the hearts of older amateur astronomers.
Both the 4se and 6se come with the excellent 25mm E-Lux plossl eyepiece. They likewise have the sturdy adjustable tripod and the computerized alt-azimuth mount that makes tracking so easy.
But there are a couple of differences of some consequence between these two telescopes. First of all, the 4se is a Maksutov-Cassegrain, unlike the 6se, which is a Schmidt-Cassegrain. Thus, the 4se has a meniscus corrector lens, which contrasts with the flat corrector lens in the 6se. The difference can lead to the 4se taking a bit longer to thermally equalize to outside temperatures, but it's less of an issue in such a small size telescope.
Virtually the only other difference between the NexStar 4se and the Nexstar 6se can be found in the difference in size between the 4se's four-inch aperture and the 6se's six-inch aperture. The first obvious difference created by the difference in aperture size is the even greater portability of the 4se. The 4se is the small and most portable telescope in the NexStar se series. As with the 6se, the 4se uses its Maksutov-Cassegrain design to provide the power of a much longer telescope in a highly portable telescope. In this case, the user gets the benefit of a four foot long telescope in an optical tube of only 13 inches. That's amazing.
The other practical result of the difference in aperture size between the Nexstar 4se and the 6se is that the 4se doesn't have the deep-space viewing capacity that the 6se has. Think about it this way, a lot of people might look at a the size difference between the 4se and 6se and ask why two inches of aperture diameter would make much of a difference at all. The fact is that the nature of circles makes this two-inch difference a highly significant one.
A little bit of geometry reveals why. The area of a circle (in this case a circular lens) is calculated by multiplying the number pi (represented by the symbol "π") by the square of the radius. Thus, the difference in the area of two circles is actually the difference in the squares of their radii multiplied by π. The difference in surface area between two circles of even slightly different radii can be shocking (remember that the next time you order a pizza!).
Here, in the case of the two-inch difference in the aperture sizes of the 4se and the 6se, the difference in aperture surface area is the difference between the aperture radius of the 4se squared and multiplied by π (50.27), and the aperture radius of the 6se squared and multiplied by π (113.1). A little bit of arithmetic reveals, consequently, that the area of the aperture of the 6se is 125% greater than that of the 4se. That means 125% more light that the 6se collects for the viewer.
The upshot of this two-inch difference is that the 4se is less capable than the 6se when it comes to true deep-space observation. Those dim, distant objects that the 6se is capable of capturing are less likely to be clear or visible to the eye of a viewer using the 4se.
The performance of the 4se's optics are superb, and they come in a small package that can conveniently be transported just about anywhere, but the fact is that if you're buying this telescope, it's largely going to be because of the mount.
The NexStar 4se (and others in this line of telescopes) comes on a computerized alt-azimuth mount, with the telescope attached to the mount via a single fork arm design. The user controls the mount using an electronic hand controller programmed with a library of over 40,000 objects.
The user need only calibrate the telescope by aligning the 4se with reference points and programming in the date and time. The scope is then able to locate those 40,000 objects in reference to the initial points. The alignment typically only takes about five minutes.
The alt-azimuth mount is a simple one that moves in two planes of motion, and the computerized motors redirect the telescope to point at objects along those perpendicular axes. This sort of mount is extremely simple to build and maintain.
Users report that the 4se and its mount are stable and solid, making this potentially a good option for astrophotography.
The total weight of the tripod, mount, and telescope is 21 lbs, which is significantly lighter than other telescopes in this line.
The NexStar 4se's tripod is sturdy, steel, and is easy and fast to set up and take down. It's the perfect accompaniment to this highly portable and compact telescope.
The NexStar 6se comes with Celestron's The Sky software Level 1 Planetarium software for exploring the cosmos on your PC. Even on a cloudy night when you can't use the telescope itself, you are free to explore all the heavens have to offer and to plan your next viewing session. Once you've done that, the software allows you to print out custom star charts to make your next session even more effective and enjoyable.
The NexStar 6se comes with Celestron's StarPointer finder scope, a red-dot finder that projects a red light in line of sight and, if properly calibrated, allows for more effective locating of celestial phenomena.
How Does It Compare?
The StarBlast has a slightly larger aperture than the NexStar 4se. The computerized tracking on the 4se puts it in a different class than the StarBlast. Still, if you're looking for a beginner scope with a nice-sized aperture and don't have as much money to spend, the StarBlast 4.5 offers nice, smooth tracking and impressive optics at a much more budget-friendly price.
The StarMax 90mm offers great stability because of its tabletop mount. The trade-off is that it doesn't offer some of the flexibility of the 4se. Because of its Mak-Cass design, which "folds" light within the tube, the StarMax also offers a similar small package, which is a boon for those looking for a grab-and-go scope, or for one that they can travel with. But the StarMax can't match the computerized tracking offered by the NexStar 4se. It is, however, much more of a budget scope than the 4se, so it's much more likely to be your first telescope.
The 114eq has a comparable aperture to the NexStar 4se, but the NexStar telescopes also offer more stability, which means they're a much better option for those looking for a scope they can use for astrophotography. Additionally, the computerized capabilities of the NexStar put it in a completely different category altogether.
The GoScope, just like other the other tabletop scope on this list, offers good stability and supremely easy setup. The trade-off is the flexibility it lacks because it doesn't have a full mount and tripod. The NexStar 4se might appeal more to you if you're looking for that flexibility, or if you're looking to do some astrophotography. In the final analysis, it's hard for the beginner astronomer to beat the GoScope's optics at such a good price, although the GoScope can't match the sheer magnitude of the NexStar's aperture, nor does it offer the game-changing computerized tracking.