Sky-Watcher Telescope Evostar 90/900 AZ3
Sky-Watcher Evostar 90/900 AZ3 – Telescope for Beginners, the Moon and Planets
Sky-Watcher Evostar 90/900 AZ3 (SK909AZ3) is an achromatic refractor telescope with a 90 mm objective lens and a focal length of 900 mm, designed for beginners who primarily want to observe the Moon, Jupiter, Saturn and other brighter objects in the night sky. The manual AZ3 mount with slow-motion controls allows more precise aiming, while the included erect-image diagonal also supports daytime nature observation.
Compared with smaller beginner refractors, the 90 mm aperture collects more light, while the 900 mm focal length provides practical magnifications for observing the Moon and planets. The telescope has no GoTo navigation or automatic tracking, so users locate and track objects manually.
If you are looking for a first telescope with a larger aperture, primarily for the Moon, Jupiter and Saturn, the Evostar 90/900 AZ3 is one of the models worth considering.
90/900 mm Optics
The objective lens diameter, also known as the aperture, is 90 mm. Aperture determines how much light a telescope can collect and how much fine detail it can resolve. With this model, it allows users to observe larger and medium-sized lunar features, basic details on Jupiter and Saturn, and brighter star clusters, nebulae and double stars.
The 900 mm focal length makes it easier to achieve magnifications suitable for lunar and planetary observation. The included Super 25 mm eyepiece provides 36x magnification, while the Super 10 mm eyepiece provides 90x magnification.
The f/10 focal ratio is well suited to visual observation of the Moon and planets. Because this is an achromatic refractor, slight colour fringing may still appear around very bright objects, but chromatic aberration is less pronounced than with short f/5 achromatic refractors.
The objective lens has an anti-reflection coating that reduces unwanted reflections from the optical surfaces.
Technical Specifications Sky-Watcher Evostar 90/900 AZ3
Feature | Value |
Manufacturer | Sky-Watcher |
Model | Evostar 90/900 AZ3 |
Product code | SK909AZ3 |
Optical design | Achromatic refractor |
Objective lens diameter | 90 mm |
Focal length | 900 mm |
Focal ratio | f/10 |
Stated maximum magnification of the optical system | 180x |
Objective lens coating | Anti-reflection |
Focuser | Rack-and-pinion focuser |
Mount | AZ3 alt-azimuth mount |
Slow-motion controls | Altitude and azimuth |
Maximum mount payload | 5 kg |
GoTo navigation | No |
Automatic tracking | No |
Tripod | Height-adjustable aluminium tripod |
Eyepieces | Super 25 mm and Super 10 mm |
Eyepiece diameter | 31.8 mm / 1.25″ |
Magnifications with the included eyepieces | 36x and 90x |
Finderscope | Optical 6x30 |
Diagonal | 45° erect-image diagonal, 31.8 mm |
Fine-adjustment controls | Flexible slow-motion cables |
Total weight | 10 kg |
EAN | 6930096650183 |
The stated maximum magnification of the optical system is 180x. However, the included eyepieces provide 36x and 90x magnification, and 90x will often deliver a steadier and sharper image of the Moon and planets in practice.
Reaching 180x requires an additional eyepiece with a suitable focal length or a compatible Barlow lens. These accessories are not listed in the standard package contents, and image quality at 180x will depend on atmospheric stability, the object’s altitude above the horizon, precise focusing and the stability of the surface beneath the telescope.
Package Contents
- Sky-Watcher Evostar 90/900 optical tube
- AZ3 alt-azimuth mount
- Height-adjustable aluminium tripod
- Super 25 mm eyepiece, 1.25″
- Super 10 mm eyepiece, 1.25″
- 6x30 optical finderscope
- 45° erect-image diagonal, 31.8 mm
- Flexible slow-motion cables
A Barlow lens is not listed among the supplied accessories for this version.
What Can You See?
The Moon
The Moon is one of the main targets for the Evostar 90/900. The 25 mm eyepiece provides 36x magnification and shows the entire lunar disc, while the 10 mm eyepiece provides 90x and offers a better view of larger craters, mountain ranges, dark lunar maria and relief along the terminator.
The most pronounced relief is usually visible along the boundary between the illuminated and dark portions of the Moon. Shadows around craters and mountains make it easier to recognise shapes and differences in surface elevation.
Jupiter and Saturn
Jupiter appears as a small but clearly recognisable disc accompanied by its four brightest moons: Io, Europa, Ganymede and Callisto. At 90x magnification, when the atmosphere is steady and the planet is sufficiently high above the horizon, its two main darker atmospheric bands may be visible.
Saturn’s rings can be clearly distinguished from the planet’s disc. Under good conditions, Titan may be visible as a point of light near the planet, while detecting finer structures within the rings requires a very steady atmosphere.
Other Planets
The phases of Venus can be observed, while Mars generally appears as a small orange-red disc. When Mars is closer to Earth, it may be possible to detect basic differences in surface brightness, but you should not expect details comparable to those seen in astronomical photographs.
Uranus and Neptune can be located using a precise star chart or astronomy app, but they will remain very small and reveal little detail.
Planets will look considerably smaller and less colourful through the eyepiece than they do in processed astronomical photographs.
Stars and Deep Sky
The 90 mm aperture allows observations of brighter open star clusters, double stars and selected deep-sky objects. Suitable targets include the Pleiades, Hyades, Double Cluster in Perseus, Orion Nebula and the brighter central region of the Andromeda Galaxy.
Galaxies and nebulae generally appear through the telescope as faint, grey structures without the intense colours visible in processed astrophotographs. Their visibility depends greatly on dark skies and distance from urban lighting.
The Evostar 90/900 is suitable for a first introduction to brighter deep-sky objects, but it is not a specialised telescope for faint galaxies, planetary nebulae or detailed observations of globular clusters. If these objects are your main priority, a Newtonian or Dobsonian telescope with a larger aperture will be a better choice.
Magnification in Practice
Combination | Magnification | Recommended use |
Super 25 mm eyepiece | 36x | Locating objects, viewing the entire Moon and observing larger star clusters |
Super 10 mm eyepiece | 90x | Lunar craters, Jupiter, Saturn and double stars |
Additional compatible accessories | Up to 180x | Occasional lunar and planetary observation under very good conditions |
The 25 mm eyepiece provides 36x magnification and a wider field of view, making it the best choice for initially locating and centring an object. The 10 mm eyepiece provides 90x magnification and is more suitable for observing lunar craters, Jupiter’s atmospheric bands and Saturn’s rings.
It is best to begin observing with the 25 mm eyepiece. Once you have located, centred and focused the object, you can switch to the 10 mm eyepiece.
AZ3 Mount
The AZ3 is a manual alt-azimuth mount that allows the telescope to move left and right in azimuth and up and down in altitude. Slow-motion controls for altitude and azimuth, together with flexible cables, allow more precise centring and manual tracking of an object, which is particularly useful at 90x magnification.
The mount requires neither polar alignment nor electrical power. It has no GoTo navigation or automatic tracking, so users locate objects themselves with the help of the 6x30 optical finderscope.
Because of the Earth’s rotation, the observed object will gradually move across the field of view. The flexible cables allow small positional corrections without roughly moving the entire optical tube.
The mount has a maximum payload of 5 kg. This is the permitted load on the mount, not the total weight of the complete setup, which is 10 kg according to the supplier.
Daytime Observations
The Sky-Watcher Evostar 90/900 can also be used to observe nature, coastlines, boats and distant landscapes. The included 45° erect-image diagonal provides an upright image, making it easier to identify and follow terrestrial objects.
The 25 mm eyepiece provides 36x magnification and is more suitable for initially locating a target. The 90x magnification can reveal more distant details, but heated and turbulent air between the telescope and the object may reduce image sharpness.
The long optical tube means that the Evostar 90/900 is not as compact as the StarTravel 80/400. It is suitable for use on a terrace, in a garden, at a holiday home or for transport by car, but it is not an ultralight travel or tabletop telescope.
Never point the telescope towards the Sun without a suitable certified solar filter securely fitted over the entire front objective lens.
City and Dark Skies
For observing from a city, the Evostar 90/900 is best suited to the Moon, Venus, Jupiter, Saturn, bright double stars and open star clusters. These objects are bright enough to remain visible under moderate light pollution.
From a darker location outside the city, open clusters, the Orion Nebula and brighter portions of other deep-sky objects become easier to see. Observations of faint galaxies and nebulae depend much more heavily on dark skies than observations of the Moon and planets.
The complete setup weighs 10 kg, making it more practical for use in a garden or on a terrace, or for transport by car, than for carrying over long distances on foot.
Astrophotography
The Sky-Watcher Evostar 90/900 AZ3 is primarily a telescope for visual observation. The manual alt-azimuth mount has no motorised tracking, which makes the complete setup unsuitable for long-exposure astrophotography of galaxies and nebulae.
With a suitable smartphone adapter, basic photographs of the Moon can be taken through the eyepiece. Short videos of bright planets are also possible, but the final result will depend on the camera, adapter, atmospheric conditions and mount stability.
If serious night-sky astrophotography is the main goal, a telescope on a stable motorised equatorial mount will be more suitable.
Why Choose a 90/900 Refractor?
A 90/900 refractor is a good choice for beginners whose priorities are the Moon and planets. The enclosed optical tube and lens-based objective do not require regular collimation of primary and secondary mirrors, simplifying preparation for observation.
Compared with the Mercury 70/700, the Evostar 90/900 has a larger aperture and collects approximately 65% more light than a 70 mm objective lens. This provides a brighter image, better resolution and access to more stellar objects, although the complete setup is also larger and heavier.
Compared with the StarTravel 80/400, the Evostar 90/900 has a longer focal length and an f/10 focal ratio, making it better suited to lunar and planetary observation at medium and higher magnifications. The StarTravel 80/400 provides a wider field of view and a more compact optical tube, making it better suited to large star fields and daytime observations when compactness is important.
For more serious observation of faint galaxies and nebulae, a Newtonian or Dobsonian telescope with a larger aperture will be a better choice. Choose the Evostar 90/900 when your main priorities are the Moon, planets, straightforward manual operation and a larger aperture than 70 mm and 80 mm refractors.
Who Is It For?
This telescope is a good choice for:
- A beginner who wants a first telescope with a larger aperture and an emphasis on the Moon and planets
- Observing the Moon, Jupiter and Saturn
- Users who want an aperture larger than 70 mm or 80 mm
- Family observations from a garden or terrace
- Bright double stars and open star clusters
- A first introduction to brighter deep-sky objects
- Daytime observation of nature and distant landscapes
- Manual observation without electronics or batteries
- A gift for a teenager or adult beginner
It Is Not the Best Choice If
- You need GoTo navigation or automatic tracking
- You plan to undertake serious long-exposure astrophotography
- You primarily want a telescope for faint galaxies and nebulae
- You are looking for a very compact travel telescope
- You do not want to locate and track celestial objects manually
- You expect planetary views comparable to processed photographs
Why Choose This Model?
The Sky-Watcher Evostar 90/900 AZ3 is designed for beginners who consider the Moon, Jupiter and Saturn more important than a very wide field of view or maximum portability. Its 90 mm objective lens, 900 mm focal length, included magnifications of 36x and 90x, and AZ3 mount with slow-motion controls provide a solid foundation for regular visual observation.
The main advantages of this model are its larger aperture compared with 70 mm and 80 mm refractors, the practical 90x magnification provided by the included eyepiece, and the option of both astronomical and daytime observation. Its limitations include manual tracking, a total weight of 10 kg, and lower suitability for faint deep-sky objects and serious astrophotography.
Professional Optics offers an expertly selected range of telescopes and accessories for different experience levels. At our store in Split, you can receive expert assistance in choosing a model according to the objects you want to observe and where you plan to use it, with competitive prices and delivery throughout Croatia and Europe.
