7-inch Telescopes (180mm)

What is a 7-inch telescope?

A 7-inch telescope is a versatile and powerful optical instrument that offers exceptional performance in observing celestial objects. With a price range that caters to both beginners and seasoned astronomers, this telescope is a popular choice for stargazing enthusiasts. Its 7-inch aperture provides superior light-gathering ability, making it 126 times brighter than the naked eye and allowing for detailed observations of faint objects in the night sky.

The magnification power of a 7-inch telescope ranges from 100x to 200x, offering a close-up view of planets, stars, galaxies, and nebulae. Equipped with high-quality eyepieces, this telescope delivers sharp and clear images, enhancing the viewing experience for users. The optical design of a 7-inch telescope typically includes objective lenses and eyepiece lenses, ensuring precise and accurate observations.

A 7-inch telescope features a focal ratio of approximately f/10, which influences its speed, field of view, and light-gathering capacity. With a focal length of around 700-800 mm, this telescope can capture celestial objects with impressive resolution and clarity. The azimuth mount of a 7-inch telescope enables precise tracking of celestial objects, while its alt-azimuth mount ensures stability and ease of use.

In terms of portability, a 7-inch telescope stands out for its compact size, lightweight construction, and adjustable tripod, making it easy to transport and set up for stargazing on the go. Whether observing planets, stars, galaxies, or double stars, a 7-inch telescope offers a rewarding viewing experience with its wide field of view and exceptional performance.

What is a 7-inch refractor telescope?

A 7-inch refractor telescope is a versatile optical instrument suitable for observing a wide range of celestial objects, including the moon, planets, star clusters, nebular clouds, and other entities in the night sky. The telescope’s 5 feet measurement is crucial for calculating its field of view and focal ratio, contributing to its observational capabilities.

A 7-inch refractor telescope has a compact size, lightweight design, adjustable tripod, and easy setup features, making it a portable and user-friendly option for astronomers. The telescope’s aperture is significant as it determines light-gathering ability, resolution, and magnification potential, with a maximum magnification of around 350x achievable.

Equipped with quality optical glass, a 7-inch refractor telescope ensures clear and detailed views of celestial objects, enhancing the overall observing experience. The telescope’s weight can range from 5.7 to 18 pounds, striking a balance between portability and stability during observations.

Featuring eyepieces for magnifying observed images, a 7-inch refractor telescope utilizes star diagonals to adjust viewing angles and create right-side-up images with a reversed left-to-right orientation. Additionally, a finder scope aids in locating and centering celestial objects before viewing them through the main telescope.

The telescope’s focal length is essential for determining image magnification, directly influencing its resolving power and observational capabilities. With a protective dew shield to prevent moisture buildup on the objective lens, a 7-inch refractor telescope ensures clear and uninterrupted views of the night sky.

Housing optical components and maintaining alignment, the tube of a 7-inch refractor telescope plays a crucial role in focusing light and creating detailed images. Mounted on an equatorial mount, this telescope can utilize ED or apo glass to reduce chromatic aberration and enhance image quality, particularly for astrophotography.

A 7-inch refractor telescope excels in observing double stars, providing clear and magnified views for detecting visual binaries and measuring their relative motion. With its combination of advanced features and user-friendly design, a 7-inch refractor telescope offers a rewarding astronomical experience.

What is a 7-inch reflector telescope?

A 7-inch reflector telescope is a powerful optical instrument designed to explore the wonders of the night sky. Featuring a tube design that houses essential optical components, this telescope serves to fold the optical path, impacting both performance and portability. The primary purpose of a 7-inch reflector telescope is to observe celestial objects, such as galaxies like NGC 7, in the visible light spectrum. With its significant aperture, this telescope excels in gathering light, enhancing resolution, and enabling clear views of deep space objects, stars, planets, and celestial bodies. The typical focal length of a 7-inch reflector telescope ranges from around 1000mm to 1200mm, providing a versatile viewing experience.
Equipped with a secondary mirror that redirects focused light from the primary mirror, a 7-inch reflector telescope offers detailed and immersive observations. The telescope’s focal ratio, magnification power of approximately 350x, and harmonic, Dobsonian-style tabletop, or equatorial mount further enhance its capabilities. Despite its average weight of approximately 16 lbs (7.25 kg), the 7-inch reflector telescope may have limited portability due to its size and weight compared to smaller telescopes.
Essential accessories for this telescope include a stable mount, eyepieces, filters, a finder scope, and a padded telescope case. Priced between $300 to $20,000 USD, with budget options available for beginners, a 7-inch reflector telescope offers a comprehensive viewing experience, allowing observers to explore the moon and other celestial objects with clarity and precision.

What can you see with a 7-inch telescope?

A 7-inch telescope allows you to see the Moon and its craters in detail. With a 7-inch telescope, you can observe Jupiter with its cloud belts and the Great Red Spot. Saturn and its bands, including the Cassini Division, are visible through a 7-inch telescope. Uranus, Neptune, and various galaxies like M 83, Whirlpool Galaxy, M81, and M82 can be seen using a 7-inch telescope. Globular star clusters such as M5, M13, M15, and M92, as well as nebulae like NGC 7027 in Cygnus, can be observed with a 7-inch telescope.

Types and Technical Specifications of 7-inch telescope

Types (Optical Design)

Dall Kirkham: Example: Takahashi Mewlon 180 C· f/ 12 Dall Kirkham Reflecting Telescope.

Hyperbolic Newtonian: Example: Takahashi Epsilon E-180 180mm ED Astrograph OTA.

Maksutov Cassegrain: Example: Sky-Watcher 180mm Maksutov Cassegrain Telescope OTA, Celestron CGX 700 Maksutov Cassegrain Telescope, Celestron CGEM II· 700 Maksutov Cassegrain, Celestron 700 f/15 Maksutov Cassegrain OTA, Celestron Advanced VX 700 Maksutov Cassegrain Telescope Bundle – CE-12035.

Maksutov Newtonian: Example: Sky-Watcher 190mm Maksutov-Newtonian Telescope OTA.

Technical Specifications

Aperture: 7-inch (180 mm)

Focal Length: 500-2700 mm 

Focal ratio: f/2.8-f/15

Highest Magnification: 360x

Light Gathering Power: 660x

Price: 1,350-5,500$

Images taken with 7-inch telescopes

Examples of 7-inch telescopes

• Celestron Advanced VX 700 Maksutov Cassegrain Telescope Bundle – CE-12035
• Celestron 700 f/15 Maksutov Cassegrain OTA
• Celestron CGEM II· 700 Maksutov Cassegrain Telescope
• Celestron CGX 700 Maksutov Cassegrain Telescope
• Sky-Watcher 190mm Maksutov-Newtonian Telescope OTA
• Sky-Watcher 180mm Maksutov Cassegrain Telescope OTA
• Takahashi Epsilon E-180 180mm ED Astrograph OTA
• Takahashi Mewlon 180 C· f/ 12 Dall Kirkham Reflecting Telescope

How do 7-inch telescopes compare to other size-telescopes

7-inch vs 8-inch telescope

8-inch telescopes provide focal lengths of 800-2415 mm (f/4-f/11.5), while 7-inch vary in focal lengths from 500-2700 mm ( f/2.8-f/15). On average 8-inch telescopes provide the highest magnification of 300-480x, whereas 7-inch telescopes can magnify 360x. However, their price range is similar, sometimes 7-inch telescopes cost more than 8-inch telescopes.

7-inch vs 9.25-inch telescope

7-inch telescopes provide a focal length of 500-2700 mm with a focal ratio of  f/2.8-f/15. In contrast, 9.25-inch telescopes vary from 2350-2500 mm in focal length with a focal ratio of f/10. Moreover, 9.25-inch telescopes provide 406-555x the highest magnification, which is 360x in the case of 7-inch telescopes.

7-inch vs 10-inch telescope

7-inch telescopes have less aperture than the 10-inch telescopes. They offer a focal ratio of f/3.9-f/10 whereas the 7-inch telescopes provide f/2.8-f/15. Besides, 7-inch telescopes offer a focal length of 500-2700 mm whereas the 10-inch telescopes vary from 1000-2500 mm in focal lengths. Though sometimes you can get 10-inch telescopes at a lesser price than a 7-inch scope.

7-inch vs 11-inch telescopes

7-inch telescope has less aperture than the 11-inch telescopes. They offer a focal ratio of f/2.8-f/15 whereas the 11-inch telescopes vary from f/2.2-f/10. Besides, 11-inch telescopes offer a focal length of 620-2800 mm whereas the 7-inch telescopes start from 500 mm to 2700 mm mm in focal lengths. Moreover, 7-inch telescopes provide 360x the highest magnification, whereas 11-inch telescopes can magnify up to 558-558.8x..