Sky-Watcher AC 90/900 EvoStar AZ-3 Astronomical Telescope
The Sky-Watcher AC 90/900 EvoStar AZ-3 represents an excellent entry point into the world of astronomy for beginning observers, as well as a practical solution for experienced astronomers seeking a portable and reliable instrument. This classic refractor with a 90mm objective offers an exceptional quality-to-price ratio, making it one of the most popular choices in this telescope category.
Superior Optical Design and Construction
At the heart of the telescope is a high-quality achromatic objective with a diameter of 90mm and a focal length of 900mm, providing a focal ratio of f/10. This ratio is ideal for **planetary observation** and double star observation. The objective is made from quality optical glass and features multiple layers of anti-reflective coating that minimize light loss and improve contrast of observed objects. Thanks to its construction, the telescope provides sharp and high-contrast images with minimal chromatic aberration.
The tube is made from aluminum, ensuring low weight while maintaining sufficient rigidity. The total weight of the telescope is approximately 4.2 kg (9.3 lbs), making it an easily portable instrument. The tube is equipped with a dew shield that protects the objective from dew formation and also serves as a sunshade to limit stray light.
Robust AZ-3 Azimuthal Mount System
The telescope is equipped with a robust **azimuthal mount AZ-3**, which is specially designed for easy operation and stable observation. The mount allows smooth movement in two axes - horizontal and vertical, facilitating tracking of celestial objects. Micrometric adjustment screws for fine positioning in both axes enable precise targeting and smooth tracking of observed targets.
The mount includes a height-adjustable aluminum tripod with a range of 710-1230mm (28″-48″), which can be adapted to the observer's height and situation. The tripod features a practical accessory tray for storing accessories such as eyepieces, filters, and other supplements. The entire construction is designed to minimize vibrations and provide a stable platform for observation.
Versatile Astronomical and Terrestrial Applications
The **Sky-Watcher AC 90/900 EvoStar AZ-3** is a universal instrument suitable for both astronomical and terrestrial observation. In astronomical mode, it enables observation of the Moon with detailed views of craters and lunar seas, planets of the solar system including Jupiter's bands and Saturn's rings. The telescope is also suitable for observing brighter deep-sky objects such as star clusters and bright nebulae.
For terrestrial observation, the telescope can be used as a powerful terrestrial scope. Its 900mm focal length provides magnifications from 18x to 180x when using appropriate eyepieces, which is ideal for observing distant objects, landscapes, or wildlife. Thanks to the erect image optics, the telescope can be used for these purposes without additional accessories.
Perfect for Beginning Astronomers
Beginning astronomers will appreciate the simplicity of operating the azimuthal mount, which requires no complex setup or knowledge of stellar coordinates. The telescope can be quickly assembled and observation can begin immediately. Quality optics provide impressive views of celestial bodies, which can inspire interest in deeper astronomical study.
Advanced Observer Benefits
Advanced observers will utilize the **Sky-Watcher astronomical telescope** as a practical and lightweight instrument for quick observation or as a backup telescope during expedition observations. Its compactness and easy portability make it an ideal companion for trips to dark skies. The AZ-3 mount allows rapid targeting of desired objects, which is advantageous when observing variable phenomena or when photographing wider fields.
The telescope is also an excellent choice for educational purposes in schools and astronomy clubs, where teachers and students appreciate its simple operation and robust construction.
Technical Specifications
- Optical Design: Achromatic Refractor
- Aperture: 90mm (3.5″)
- Focal Length: 900mm
- Focal Ratio: f/10
- Mount Type: AZ-3 Azimuthal
- Tripod Height Range: 710-1230mm (28″-48″)
- Total Weight: Approximately 4.2kg (9.3 lbs)
- Tube Material: Aluminum
- Useful Magnification Range: 18x to 180x
Recommended Accessories
To expand observation possibilities, we recommend supplementing the telescope with quality eyepieces of various focal lengths. For example, a 25mm eyepiece for low magnification and wide field, 10mm for medium magnification universal use, and 6mm for high magnification planetary observation. Useful additions include filters - a moon filter to reduce brightness when observing the Moon and colored planetary filters to increase contrast of details on planets.
Additional Recommended Equipment
- Barlow lens (2x) for doubling magnification of existing eyepieces
- Star diagonal for comfortable viewing angles
- Red LED flashlight for preserving night vision
- Carrying case for protection during transport
- Solar filter for safe solar observation (with proper supervision)
What You Can Observe
Lunar Observation
Detailed views of lunar craters, mountain ranges, and maria. The f/10 focal ratio provides excellent contrast for lunar surface features.
Planetary Observation
Clear views of Jupiter's cloud bands and four largest moons, Saturn's rings and largest moon Titan, Mars during opposition showing polar ice caps and surface features, and Venus showing phases.
Deep Sky Objects
Bright star clusters like the Pleiades and Double Cluster, the Orion Nebula and other bright emission nebulae, and double stars with close separations.
Terrestrial Use
Wildlife observation, landscape viewing, and architectural details at distances up to several kilometers with crystal-clear image quality.
Setup and Maintenance
The Sky-Watcher AC 90/900 EvoStar AZ-3 requires minimal maintenance. The optical surfaces should be cleaned only when necessary using appropriate lens cleaning materials. The mount mechanisms benefit from occasional lubrication of moving parts. Storage in a dry environment helps preserve the telescope's longevity.
Initial setup takes only minutes - simply attach the tube to the mount, insert the diagonal and eyepiece, and begin observing. The intuitive design makes it perfect for spontaneous observation sessions.
