Sky-Watcher BK1025 AZ Pronto 102/500 Telescope

Sky-Watcher BK1025 AZ Pronto achromatic refractor with a 102 mm objective diameter and 500 mm focal length. The large aperture for a refractor and relatively short focal length allow this telescope to deliver a very wide field of view, making it an excellent choice for those wishing to observe large open clusters, extensive nebulae, or entire sections of the Milky Way. The telescope is lightweight, and its compact size makes it easy to transport and store. It’s also a great solution for beginner night sky observers. The wide field of view simplifies locating objects in the sky.

Included in the set are a Star Pointer finder and dovetail clamps that allow the refractor to be mounted securely. It’s well-suited as a compact device for beginner observers, enabling comfortable observation of the Moon, Sun (with a proper solar filter), and planets. However, this telescope excels at observing large star fields and broad sections of the Milky Way. With appropriate eyepieces, it can offer a field of view comparable to wide-angle binoculars while maintaining typical telescope range. These features make it ideal for observing comets, particularly those with extensive tails, and it’s very suitable for variable star observation using the visual method. With short-focus eyepieces, the telescope allows observation of lunar features and basic planetary viewing (for more detailed views, Maksutov-type designs or refractors with longer focal lengths are recommended). The telescope's design also makes it a useful tool for nature observation.

Optical System
This telescope is a classic, two-element achromatic refractor. This optical arrangement guarantees good image brightness. The telescope collects about 212 times more light than the human eye at night, allowing observation of objects up to nearly 12.6 magnitudes (with the naked eye limit being 6 magnitudes). The lens size is also linked to optical resolution, which in this telescope enables the resolution of stars more than 1.4" apart.

Mount
The Sky-Watcher AZ PRONTO is a lightweight, portable altazimuth mount made from aluminum, designed for small telescopes weighing up to 3 kg and equipped with micro-motion on both axes.

The aluminum telescopic legs of the tripod can be extended and locked at any height with leg locks. It comes with two flexible micro-motion control knobs, one for smooth vertical movement and one for horizontal. Each axis allows two positions for the control knobs.

The mount can also be manually rotated around each axis, allowing for quick adjustments in height and easy tracking of distant moving objects.

Focuser
The telescope is equipped with a 2" eyepiece focuser. The set includes a 1.25" reducer, with a standard 1.25" 45-degree prism diagonal attached. The telescope is compatible with 1.25" accessories by default, but to install 2" eyepieces, an additional 2" diagonal attachment is required. For optimal image quality, dielectric diagonals are recommended. The rack and pinion focuser is compatible with Sky-Watcher’s electronic focusers.

Astronomical Observations

• Solar System – To reduce chromatic aberration effects for bright objects, an aperture cap with a reducing hole can be placed on the objective:

  • Lunar surface features larger than 2 km.
  • Sunspots and their structure (an objective filter is essential for solar observation).
  • All planets of the Solar System.
  • Phases of Mercury and Venus.
  • Small Mars disk, with polar caps and continent outlines visible during opposition.
  • Jupiter's equatorial belts and Galilean moons.
  • Saturn's rings and its largest moon, Titan.
  • Uranus and Neptune as star-like points.
  • Movement of asteroids against the background stars.
  • Observation of bright comets.

• Stars

  • Approximately 1.1 million stars across the sky, down to around 12.6 magnitudes.
  • Double and multiple stars with separations greater than 1.4".
  • Colors of the brightest stars.

• Nebulae and Deep Sky Objects

  • Nearly all objects in the Messier catalog.
  • Hundreds of globular clusters, with the largest resolvable into individual stars at the edges.
  • Hundreds of open clusters.
  • Bright nebulae, with visible structural details in many cases.
  • Bright galaxies, with spiral arms visible under dark sky conditions.

• Terrestrial Observations

  • This type of telescope is highly suitable for terrestrial observation. A prism diagonal allows the telescope to be used as a high-quality spotting scope with the ability to photograph at a given focal length.

Equipment

• Diagonal prism 1.25" 45°
• Finder: Star Pointer
• Smartphone adapter
• Eyepieces: 1.25" - Photo 20, Photo 10

Specifications

• Catalog Number: SW-2111
• Telescope Optical System: Refractor
• Mount Type: Altazimuth
• Aperture: 102 mm
• Focal Length: 500 mm
• Focal Ratio: f/5.0
• Stellar Magnitude Limit: 12.6
• Maximum Useful Magnification: 204x
• Maximum Resolving Power (Rayleigh): 1.4"
• Light Gathering Power: 212x
• Tube Weight: 2.5 kg
• Tube Length: 500 mm
• Tripod Type: Aluminum
• Mount Control: Manual
• Eyepiece Focuser Type: Rack and Pinion
• Eyepiece Focuser Diameter: 2"
• Eyepiece Focuser Micro Adjustments: No
• Mounting Rail: Vixen
• Warranty Period: 60 months