The Celestron AstroMaster 70AZ is a 70mm refractor telescope with a 900mm focal length mounted on a simple manual altazimuth tripod. Its long f/13 optical system is particularly suited to observing the Moon, bright planets and other relatively bright targets.
Unlike a computerized telescope, the AstroMaster 70AZ has no motors, GoTo system or electronic tracking. Objects are located with the StarPointer red-dot finder and the telescope is then moved manually using the mount’s pan handle.
The telescope also includes an erect-image diagonal, allowing it to produce correctly oriented views for daytime terrestrial observing as well as astronomy. Its straightforward manual design keeps setup relatively simple, although the 70mm aperture places clear limits on its ability to show faint deep-sky objects.
70mm f/13 Refractor Optics
The AstroMaster 70AZ uses a 70mm objective lens with a 900mm focal length, giving it a focal ratio of approximately f/13. The glass optics are fully coated to improve light transmission.
The relatively long focal length naturally favors lunar and planetary observing. It also makes useful magnifications easy to achieve without requiring extremely short-focal-length eyepieces.
As an achromatic refractor, the telescope can show some chromatic aberration around particularly bright objects. Its relatively long f/13 focal ratio helps reduce this effect compared with shorter achromatic refractors, although it does not eliminate it completely.
The telescope is supplied with 20mm and 10mm eyepieces, providing magnifications of 45× and 90× respectively.
Manual Altazimuth Mount
The AstroMaster 70AZ uses a manual altitude-azimuth mount on an adjustable steel tripod. A pan handle allows the telescope to be moved up and down and from side to side, while a clutch controls the movement of the mount.
There is no computerized alignment procedure or electrical power requirement. The StarPointer red-dot finder helps aim the telescope toward a target, after which the observer centers the object in the eyepiece.
Because the mount does not track automatically, objects gradually move across the field of view as Earth rotates. The telescope must therefore be adjusted manually from time to time to keep a target centered, particularly when observing at higher magnifications.
What Can You See Through the AstroMaster 70AZ?
The Moon is one of the telescope’s strongest targets. Its craters, mountain ranges, maria and shadows along the terminator can be observed clearly, with the supplied eyepieces providing useful low- and medium-power views.
The bright planets are also accessible. Jupiter’s four Galilean moons can be seen, along with its main cloud belts under suitable conditions, while Saturn’s rings can be distinguished from the planet itself. Venus shows its changing phases, and Mars appears as a small disk when favorably positioned.
Beyond the Solar System, the 70mm aperture can show bright open clusters, double stars and some of the brighter deep-sky objects. Faint galaxies and nebulae are much more challenging because of the telescope’s relatively modest light-gathering ability.
The 900mm focal length also produces a narrower field than shorter refractors, so very large star fields and extensive deep-sky objects are not the AstroMaster 70AZ’s strongest targets.
Daytime Terrestrial Viewing
The supplied erect-image diagonal produces correctly oriented views, allowing the AstroMaster 70AZ to be used for terrestrial observation as well as astronomy.
Distant landscapes, wildlife and other terrestrial subjects can therefore be observed during daylight. The adjustable tripod allows the observing height to be changed, while the manual altazimuth mount provides straightforward pointing.
This dual-purpose capability is a useful distinction from telescopes configured solely around astronomical observing, although a dedicated spotting scope may be more convenient for frequent terrestrial use.
Portability and Setup
The AstroMaster 70AZ requires no tools for normal setup, and the mount and tripod are supplied preassembled. The optical tube attaches to the mount using a dovetail connection.
The complete telescope package weighs approximately 10.8 lb (4.9 kg), while the optical tube itself weighs about 2.9 lb (1.3 kg). This makes the complete setup relatively easy to move compared with larger astronomical telescopes.
The tripod can be adjusted from approximately 32 to 51 inches (81 to 130cm) in height, allowing the eyepiece position to be adapted for different observers and targets.
Limitations to Consider
The AstroMaster 70AZ’s main limitation is its 70mm aperture. This is sufficient for useful views of the Moon, bright planets and a selection of brighter deep-sky objects, but substantially larger telescopes gather more light and reveal fainter targets more readily.
Its 900mm focal length also means the telescope is not particularly well suited to very wide-field observing. Large open clusters and sweeping Milky Way star fields are more naturally matched to shorter-focal-length instruments.
As an achromatic refractor, some color fringing can appear around bright targets, particularly the Moon and bright planets, although the relatively slow f/13 focal ratio helps keep chromatic aberration under better control than in many shorter achromatic refractors.
Finally, the mount is entirely manual. There is no GoTo object locating or motorized tracking, so finding and following targets remains the observer’s responsibility.
Who Is the AstroMaster 70AZ Best For?
The AstroMaster 70AZ is best suited to observers looking for a simple, lightweight telescope for the Moon, bright planets and brighter star clusters, with the added option of daytime terrestrial viewing. Its manual mount and modest 70mm aperture make it less suitable for observers wanting computerized object finding, automatic tracking or stronger deep-sky performance, but they also keep the telescope straightforward to set up and use.
Specifications
- Optical Design: Refractor
- Aperture: 70mm (2.76 inches)
- Focal Length: 900mm
- Focal Ratio: f/13
- Optical Coatings: Fully coated
- Mount: Manual altitude-azimuth
- Supplied Eyepieces: 20mm and 10mm
- Supplied Magnifications: 45× and 90×
- Finder: StarPointer red-dot finderscope
- Diagonal: 1.25-inch erect-image diagonal
- Optical Tube Length: 685mm (27 inches)
- Optical Tube Weight: 2.9 lb (1.31 kg)
- Total Kit Weight: 10.8 lb (4.9 kg)
- Tripod Height Range: approximately 32–51 inches (81–130cm)