Apertura Essential 7-21mm 1.25" Zoom Eyepiece
The Apertura Essential Zoom Eyepiece: 5 Focal Lengths in One
The Apertura 7-21 Essential mm Zoom Eyepiece is an excellent solution for astronomers who don't want to constantly swap eyepieces during observations. Whether you’re staying close to home with lunar and planetary exploration or peering further into space to behold the wonders of vast deep space nebulae, this Apertura Zoom eyepiece is up for the challenge!
Whether you’re looking for a higher or lower magnification eyepiece, this Apertura Essential Zoom Eyepiece has you covered! Zoom eyepieces are capable of adjusting their focal length while remaining connected to the telescope. Infinitely adjustable between 7 mm and 21 mm, this one eyepiece comes with five individual focal lengths of 7 mm, 9 mm, 12 mm, 16 mm, and 21 mm. With this variety of focal lengths you can explore the rich details of both terrestrial and celestial scenes. All you need to do is rotate to your desired focal length value.
Apertura Essential Zoom Eyepiece At a Glance
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Variable Focal Length Eyepiece!
This Apertura zoom eyepiece not only holds the power of an entire eyepiece collection in a single unit, it comes equipped with great optical performance and 1.25" filter compatibility! Read more below.
About the Essential Zoom Optics!
With a range of 7 mm to 21 mm focal lengths available, this Apertura Zoom eyepiece captures the typical high, medium, and medium-low power eyepiece perspectives within a single eyepiece! The Apparent Field of View (AFOV) can range from ~40° to 57°, and most times a step up from the standard entry-level options that are typically around 40° or lower. A larger AFOV gives a more spacious appearance, as opposed to tighter views that can feel as though you are “looking through a straw.” The eye relief is a comfortable range of 16.3 mm ~ 18 mm.
Quality Build!
Weighing just 0.75 lbs., this Apertura Essential Zoom Eyepiece eyepieces includes a
1.25” threaded barrel for compatibility with 1.25" threaded
filters. The
Apertura 1.25" Lunar & Planetary Filter Set (not included)
is an invaluable aid in getting the most out of your observations, as each filter
enhances different aspects of planetary and lunar features! This eyepiece would be a great addition to your
visual collection at an exceptional value!
Frequently Asked Questions
What is an eyepiece?
An eyepiece is a group of lenses housed in a small package that is closest to the eye when used with a telescope, microscope, or spotting scope. The eyepiece provides a particular magnification when paired with a telescope, therefore most amateur astronomers use a variety of eyepieces to change magnification for different types of objects. The eyepiece nomenclature is expressed in its focal length in millimeters.
What is eye relief?
Eye relief is the distance you can situate your eye from the eyepiece lens and still obtain a full, unobstructed field of view. Eye relief that is either too short or too long can make observation uncomfortable, especially if you wear glasses. Generally speaking, eyepieces with shorter focal lengths have shorter eye relief. When necessary, you can increase eye relief without sacrificing magnification by swapping a high-power eyepiece for a low-power eyepiece and a Barlow lens.
What size eyepiece is best for viewing planets?
The most useful eyepieces for planetary viewing are those with about 100x magnification. It is ideal to have either a second eyepiece or a compatible Barlow lens to achieve, on average, somewhere between 100x to 250x magnification. Viewing the planets is best under as much magnification as the telescope and seeing conditions will allow.
What is the magnifying power of an eyepiece?
To figure out the magnification of an eyepiece, simply divide the focal length of the eyepiece into the focal length of the telescope. The result is the magnification provided in your particular telescope or one with the same focal length.
Are zoom eyepieces any good?
A zoom eyepiece is a type of eyepiece that has the ability to change its focal length (called variable focal length) using manual adjustments by the user. This variable focal length allows users to use one eyepiece to switch between focal lengths instead of having to switch out eyepieces. This streamlines the observation process and minimizes the change of equipment management, since there is less removal and reinstallation of eyepieces in a single observation.
Astronomy Hub: Your one-stop-shop for Astronomy Knowledge!
Our Gear Experts have compiled a wealth of information to help expand your astronomy knowledge! Below you’ll find links to articles, videos and "how-to" guides. Just one more reason that our Astronomy Hub is a one-stop-shop for all your astronomy and astrophotography needs!
| The Ultimate Telescope Eyepiece Guide |
| Eyepieces and Observing the Planets |