There are two deal-breakers for the Gskyer 600x90mm. The first one is the terrible mount, and the second one is the price.
Although Gskyer 600x90mm has decent optics, a telescope is not complete without a proper mount. You won’t be able to enjoy your time stargazing if the mount is shaking in the slightest breeze. The smallest movement will make you lose the object you are trying to observe, which is the case with this telescope.
A weak mount is especially discouraging at high magnifications. As you go higher in magnification power, 80-90x magnifications for example, it will become harder and harder to follow the object you are trying to observe in the sky. That is why even though you manage to get a decent view of, Saturn for example, you will constantly try to keep it in the view, which will probably frustrate and discourage you.
The mount has awful build quality.
There are much better choices for the same price.
The optics of this telescope are not bad. The lenses are properly coated, and the optical power is enough to view some major details such as Ring’s of Saturn, moons of Jupiter, and Mars as a red dot. The Moon shows a lot of details as it does with most other telescopes.
If there is a problem to be found in the optical design of this telescope, it is the short optical tube. An ideal refractor would have at least an f/8 focal ratio, which would require a much longer, 720mm optical tube. Gskyer 600x90mm, as you might understand from the name, has a shorter, 600mm optical tube. This results in color defects around bright images, called chromatic aberrations.
Other than that, the optical design is fine. It is not the best you can get at this price range, but it is not below-average either. If you are going for pure optical power, you should get the highest aperture telescope you can find. Aperture is king at the budget price range.
The mount is so bad it would be considered useless for a digital camera. It cannot provide any kind of smooth motion in the vertical or horizontal axis, and stability is out of the question.
The main problem is plastic on plastic parts. Most budget telescopes come with plastic mounts, but they have bearings implemented on the joints that are important for the optical tube movement. Gskyer 600x90mm doesn’t have any. It is pure plastic on plastic hell.
The tripod is much better than the mount. It is stainless steel and sturdy enough to carry the optical tube.
Overall the base is a deal-breaker. It is nowhere near enough for a 90mm refractor or any kind of telescope.
The accessories are, similar to the optical quality, average. The 25mm eyepiece and the 6×30 finder are some of the better accessories that can be found in this price range. Especially the 6×30 finder, which is vastly better than any 5×24 finder.
The 10mm eyepiece is ideal for planetary detail. It provides 60x magnification, which is close to the magnification limit of this telescope. On the other hand, it is not easy to get a decent view with the 5mm eyepiece.
Unfortunately, the 3x Barlow is sent with most budget telescopes so that the telescope “seems” more powerful than it already is. The reality is you can’t get this telescope to work around 360x or 180x magnification. The image is disappointingly blurry and dim with the 3x Barlow.
The 45-degree diagonal is not ideal. It makes it incredibly hard to observe objects that are higher than 80-degrees in the night sky. It also slightly lowers the image quality. Not my favorite part of this scope.
The diagonal is not ergonomic.
The most important drawback of the package is the terribly made mount. There is nothing about it that is worth praise.
The second, slightly less important drawback is the price. Although Gksyer 600x90mm’s price is not senseless, there are much better models for the same price.
I can’t find any reason whatsoever to buy this telescope. It not well-made, it’s accessories are average, it comes with a cheap mount and, it is overpriced. Please don’t pay attention to the Amazon reviews and get a better telescope. You can start by checking out our rankings.