Celestron ExploraScope 114AZ Reflector Telescope Review: Flawed Optics
ExploraScope 114AZ is an attempt to make higher profits with cheap mirrors.
Celestron ExploraScope 114AZ seems like a cheap, high-powered telescope. The problem is this is achieved with a flawed optical design. Let me explain.
You are probably considering buying this telescope because of the specs you have seen on the poster. The thing you don’t know about is that these specs are achieved with an imperfect, absurd optical design.
Falling for this scam is definitely not your fault. Celestron should inform their beginner customers about this, but instead, they choose to make higher profits.
The optical design is what is called a “bird-jones“. This design was created so that high-powered, small telescopes could be manufactured with a cheap, spherical mirror. The problem is it is really hard to manufacture a good corrector lens for this design. The slightest misalignment creates annoying image defects.
The corrector lens also lowers image brightness and sharpness. A great telescope should have as little barriers as possible between you and the object you are observing. As the number of lenses increases in a telescope, unavoidably, the image quality decreases.
Another problem with the corrector lens is collimation. Collimation is an alignment procedure you have to do every now and then to fix your telescope’s optics. With a normal, reflector telescope, it takes only 15 minutes. With a Bird-Jones, it is almost impossible to do. Even an experienced astronomer would have problems collimating a Bird-Jones telescope. This alone is a reason why not to buy this telescope.
I shouldn’t be too hard on the optical design. If the optics are collimated, it produces “OK” images for its price. It is able to show moons of Jupiter, rings of Saturn, and a good amount of detail on the Moon. But as soon as optics get misaligned, the image quality starts to decline really fast.
The mount is mostly plastic and provides average stability. It has two connections to the optical tube. The design is better than a single connection altazimuth mount, but it still is not solid enough for the optical tube.
The motions on the vertical and horizontal axis are not smooth enough for a pleasant observation. These kinds of mounts are designed for long refractors, a short Newtonian telescope is not able to apply enough force, and it is not easy enough to move.
The slow-motion control for the horizontal axis is pretty useful. Gravity creates annoyance for heavy optical tubes, and slow-motion controls solve this problem. However, there is no slow-motion control for the horizontal axis.
The tripod is the best part of the whole telescope. It is aluminum and surprisingly sturdy. It also has an eyepiece tray in the middle. There is a connection on each leg so it can fold and fit in a bag.
At this price range, most mounts are wobbly and plastic. The reason why I recommend tabletop Dobsonian’s. Their mounts are rock-solid and smooth. They are easier to manufacture.
The only usable accessory is the 20mm eyepiece. It is a budget, mid-magnification eyepiece with a small lens.
The 4mm eyepiece is useless. It provides too much power, and the eye-relief is too small. The image it provides is fuzzy, and optics become almost impossible to focus with this eyepiece.
The red dot finder is strongly attached to the optical tube. It is easy to remove and attach it. It is sturdy and doesn’t bring up any problems.
The focuser is mostly plastic. It slightly wobbles at high-magnifications, but the problems it creates doesn’t come near the problems that are created by the flawed optical design.
The 3x Barlow is another useless accessory. A 3x Barlow is really hard to manufacture. What Celestron provides is more of a toy than a piece of serious astronomy equipment. You won’t get any kind of decent image with this lens.
The optical design is a poorly done bird-jones. Which is funny because the only reason a person buys a telescope is to get powerful optics to observe the Universe.
The 4mm eyepiece is useless, as well as the 3x Barlow lens.
The mount doesn’t provide smooth enough motion for stargazing. It is also not stable enough.
This telescope shouldn’t be bought in any case. Not because it is complete trash. It may provide decent images with correct collimation. The reason it shouldn’t be bought is that there are vastly better models being sold at for the same price.
I recommend spending your hard-earned money on a better telescope, even if you are a complete beginner.