Even though it’s not a household name, Taiwan-based GSO is actually one of the biggest and most productive telescope companies in the world.
GSO stands for Guan Sheng Optical (guan sheng may roughly translate to “crown”), and its many models and brands have been on the market for decades.
Newtonian, and even Cassegrain telescopes are in wide use right now, but often under a different label that might make it hard to identify as GSO.
These are the GSO-made brands worth knowing
GSO has been providing telescope manufacturing services for many brands, some of which are or were famous names in the telescopic and optical world.
GSO is known for developing cheaper telescopes by combining RC and Newtonian optics for an optimal price while maintaining great properties when gazing. They were also known to introduce carbon fiber for mass manufacturing their trusses.
And, as mentioned, they’re a popular white-label manufacturer that shows up more often than you might realize.
Zhumell is one of the brands you’ve almost certainly come across.
Based in Omaha,, Nebraska, they used GSO-developed technology for decades. Unfortunately Zhumell shut its doors a couple of years ago, but their telescopes are still around.
The Zhumell Z50 is a particularly well-known entry-level telescope, which lots of younger stargazers begin with.
Apertura was founded by amateur astronomy enthusiasts that focused on producing and delivering great telescopes for amateurs. That meant price-to-quality was a key factor, which led them to a manufacturing partnership with GSO.
The Apertura AD8 is a Dobsonian telescope with an 8-inch parabolic mirror with 93% reflectivity. That’s rare in this price range, which attests to the value that Apertura has generally delivered.
A brand coming from Orion Telescopes that’s seen much success over the past couple of years is Skyline. They reached out to GSO to partner up and create a line of telescopes with the lenses, mirrors, and casings that GSO is known for.
One popular result of this collaboration was the Skyline Base 100S Newtonian reflector, which proved easy to use while maintaining a clear and sharp image of the night sky.
TS Optics, or TSO, is one of the better-known brands on this list. They focus on amateur, semi-professional, and low-cost professional Newtonian, Dobsonian, RC in the US and other parts of the world.
One of their more popular models (especially on the European market) is the Starscope1306, which has everything that a beginner would need. The 130mm aperture, 650mm focal length, and max magnification of 130x come with an equatorial mount and can be added to an aluminum tripod.
Astro-Tech creates versatile refractors to suit a wide range of observation scenarios.
They are known for very good apochromatic refractors such as the Astro-Tech AT115EDT, known above all as a great value for intermediate to advanced hobbyists.
Are GSO telescopes any good?
GSO has produced some high-quality optics and mirrors over the years, but is best known for mass production of cheap telescope parts, including mirrors, optics, and frames and casings. They were the first to establish mass production of carbon fiber trusses, too.
With the backing of some well-known brand names around the world and years of experience in producing telescopes, GSO has gone in the direction of creating the best possible quality telescopes for the least cost.
This series of telescopes are far from top-quality, according to many reviewers, but they’re entirely usable. The various telescope/refractor types and sorts for different purposes they’ve created will meet at least the basic needs for amateurs and intermediates, if not more than that.
The pivotal moment for the company was the introduction of 6″, 8″, and 10″ Cassegrain refractor in mass production. The Cassegrain design was notoriously to produce at scale due to its delicate structure, so it was no mean feat for GSO to pull off!
Their Cassegrain refractors, especially the 8″ ones, are a good budget alternative to more costly and popular competitors. Users have said the collimation was great, the image quality was more than adequate, and there were usually no stray light issues.
The lenses and mirrors were created cheaper with usually 91-94% refraction rate, which is more than enough for quality imaging and gazing for the given price.
Even 0.5% better refraction can add hundreds of dollars to the retail price!
On top of that, since many brands already use GSO telescopes, buying from GSO themselves basically cuts down the middle-man, reducing the price even more on the user’s end.
How much do GSO telescopes cost?
GSO telescopes are cheaper than most others of comparable quality, but prices range from around $100 into the thousands.
They have developed a cost-efficient technology to create great quality-to-price refractors you can use for decades if you maintain them correctly.
The fact of the matter is that their telescopes are usually rebranded by bigger brands and placed on the market with higher costs. It remains unknown how many companies at least partially depend on their parts and services, but we can speculate it is significantly more than the numerous companies that rebrand whole products from GSO.
With that said, you can expect 10-25% cheaper products coming directly from GSO compared to the similar or even lower quality products sold by other brands.
Other brands worth considering
There are several great brands on the market anyone should consider, and we will leave two names here.
Celestron is one of the most commonly mentioned brands that create quality telescopes that have become staples in amateur and even professional astronomy. They are known for creating quality Newtonian and RC telescopes, as well as providing great add-ons and accessories.
Meade Instruments is another popular brand among astronomers that are on the higher end of the price range, yet they nevertheless create lasting and quality refractors that are easy to use and good for any astronomical profile.
To sum it up, we are happy to introduce you to the silent hero of astronomy that’s been working hard for a long time to provide astronomy lovers around the world quality lenses and mirrors that are essential for cheap commercial refractors and telescopes.
Though there is common knowledge about products coming from different countries, it seems the tides are turning, and what once could be just prejudiced, the challenge of our current time is to shift and change the expected quality of products coming from different countries.
In the ’80s, for example, Japanese manufacturers were the Mercedes of the optics world. But trends have been shifting in favor of other countries, like Korea, Taiwan, even China, and Vietnam in some cases.
That’s certainly been the case with GSO, a brand that’s been helping new astronomers worldwide to immerse themselves in this magnificent hobby.
If you’re looking for a first telescope, we suggest starting with this basic guide to how to choose. It also features three of the very few budget models we’d actually recommend!