Celestron SkyMaster Astronomical 20x80mm Giant Binocular

By the Astronomy and Photography Online Staff

Celestron SkyMaster Astronomical 20x80mm Giant Binocular
Illustration courtesy of Celestron International.

Celestron has a long history of offering well made binoculars of superior optical quality at a reasonable price. We recently reviewed Celestron's SkyMaster 25x100 astronomical binoculars and found that they ably carry on Celestron's praise worthy binocular tradition. The drawback to the 25x100 giants is simply their size and weight, which makes finding an adequately strong and stable mounting system very difficult.

For this review we selected Celestron's next size down in giant binoculars, the SkyMaster 20x80 Astronomical Binoculars. Once again, the test binoculars were provided by Optics Planet (online at www.opticsplanet.com or call 800-504-5897). In fact, they sent us two identical Celestron binoculars to compare. They arrived packaged in an outer cardboard shipping container and inner decorative cardboard box. Inside the latter was a simply nylon binocular case for these giants. Carrying straps are provided for the case and the binocular.

These Celestron 20x80mm giants are large, but not unmanageable, binoculars. They measuring 12.5 inches in length, are slightly more than nine inches wide across the objectives and weigh about 4.7 pounds. The optics are multi-coated and inside are top quality BAK-4 prisms. Focusing is by means of a center focus adjustment with an individually adjustable right eyepiece. The center focusing and right eyepiece adjustments are smooth and easy to use, as is adjusting the binocular for the correct interpupillary distance. These 20x80's are much easier to adjust and use than the 25x100 giants we recently reviewed.

Here are some general features and specifications for the SkyMaster 20x80mm binocular:

  • Item #71018
  • 20x magnification porro prism binocular with BAK-4 prisms
  • Multi-coated optics
  • Enhanced structural reinforcement to the main binocular body
  • Protective rubber body covering
  • Waterproof
  • 80mm objective lenses
  • Angular field of view - 3.7 degrees
  • Linear field of view - 195 feet at 1000 yards
  • Exit pupil - 4mm
  • Eye relief - 18mm (suitable for eyeglass wearers)
  • Minimum focusing distance - 108 feet
  • Rubber ocular eyecups that can be folded back to accommodate eyeglass wearers
  • Weight - 75 ounces
  • Length - 12.5 inches
  • Integral tripod adaptor rod
  • Deluxe nylon carrying case with strap
  • Lens caps included
  • Celestron Lifetime No Fault Warranty
  • 2009 MSRP $145.99 (available direct from Celestron--www.celestron.com--and from Celestron dealers worldwide)

Celestron's Lifetime and No Fault warranty deserves comment. Celestron binoculars are warranted free of defects in workmanship and materials for the useable lifetime of the product and Celestron will repair or replace them for free. The No Fault provision means that regardless of how the binocular may have been damaged or destroyed, Celestron will repair or replace it without question for a nominal fee of $25. I know of no other company in the industry that offers this kind of warranty.

The Celestron 20x80 Astronomical binoculars are provided with an integral tripod mounting system. There is a .665 inch diameter rod fixed along the axis of the binocular. A cylindrical tripod mounting foot slides back and forth on this bar and is tightened in place by a large knob. This system proved marginal for the massive 25x100mm giants previously reviewed, but it works much better for the lighter 20x80mm giants. We would still like to see the rather small "foot" at the bottom of the binocular's tripod mount replaced by something larger. Measuring only 1.3" in outside diameter, it would be nice to have more surface contact area to prevent the binocular from "squirming" on the head of a tripod. This tripod mounting system worked well for terrestrial observations and adequately for casual binocular astronomy.

Terrestrial Viewing

The Celestron giants can be mounted on a heavy-duty camera tripod for daylight terrestrial viewing. A "fluid" video head would be an asset here, to allow smooth aiming. We made due with Bogen's medium size #3221 tripod legs topped by a conventional #3047 head. This photo tripod is recommended for use with cameras up to 4x5 inch format and it proved adequate for terrestrial viewing, but inconvenient and marginal for astronomical viewing.

We tested the 20x80's daylight performance on some prominent objects and it was impressive. At the binocular's minimum focusing distance, dandelion puffs were rendered with complete detail. At a laser rangefinder verified 216 yards, we could count the individual needles on the branch of a fir tree. At 582 yards, we could see the individual leaves on a distant oak tree. We could resolve the individual leaves on a maple tree at the top of a hill, but we could not measure the range to that maple tree, because it is well beyond the 1000 yard maximum measuring distance of the Leupold rangefinder we were using!

We looked at the same objects with Celestron 25x100 giants as well as the 20x80's and, despite the larger binocular's slightly greater magnification, could detect no difference in their ability to resolve detail. Three of us compared the two 20x80 binoculars we received for this review and found absolutely no difference between them, either optically or mechanically. This speaks well for Celestron's quality control.

A birdwatcher operating from a tripod would find these binoculars very handy. Hunters could use them to estimate the quality of a potential trophy from long distance. People traveling by car or motor home on vacation would likely find them useful to have along and practically anyone gets a grin from looking through the Celestron 20-80 giant binoculars.

Astronomical Viewing

Celestron SkyMaster Astronomical binoculars are, as the name implies, especially convenient for observing (relatively) large swaths of the night sky. They are ideal for viewing large astronomical subjects, such as open clusters and star fields. They are very bright and you do not have to squint one eye to use them. The view through the 20x80 giants is correctly oriented, which makes "star hopping" to locate objects relatively easy.

The best mounting system we had available for this review was a Bogen #3035 tripod leg set with a Bogen Side Arm attached to the top of the tripod and a Bogen #3057 head attached to the business end of the Side Arm. This is the same rig we used for the Celestron 25x100 Astronomical binoculars previously reviewed. The other end of the Side Arm can be counterbalanced to off-set the weight of the head and binocular by hanging some sort of weight from it, such as a half-gallon jug of water secured by a short length of nylon line. A parallelogram mount would be ideal, but they usually must be designed and custom made by an engineer/machinist. (Our Rocky Hays, for example.)

Marginal for the nine pound 25x100 giants, the Bogen 3035/3057 plus Side Arm combination worked much better with the lighter and more compact 20x80 giants. The Side Arm allowed enough offset so that we could get under the binoculars to view the night sky and the three-section #3038 legs are tall enough to allow viewing from a standing position. We used the tripod's geared center column to make small height adjustments. In addition, the angle of the legs relative to the center column is adjustable, which is convenient for use in the field.

This is a heavy, expensive and somewhat cumbersome way to mount giant binoculars, but it allowed us to scan the heavens with the 20x80's. Although it lacks slow motion controls, this tripod system proved superior to the Celestron recommended Heavy Duty Alt-Azimuth Tripod for use with giant binoculars. (There is a review of that tripod on the chuckhawks.com Photography and Astronomy page.)

We managed to view a few common astronomical objects with the 20x80's from the backyard of Chuck's mobile home. This is located about 13.5 miles from the city of Eugene, Oregon, but it is not at a dark sky site, as every home has a light at the corner of their driveway. However, it is darker than a typical urban residential area, because we did not have the city sky glow to contend with.

First, we looked at the moon, which is impressive when viewed through the big SkyMasters. Lots of detail and, because the moon is a plane surface (rather than a point source of light), the apparent sharpness is very good. Using both eyes is a definite advantage compared to a telescope operating at the same 20x magnification. We were not bothered by color fringing or flare, although these are apparent against the black night sky.

Next, we viewed Jupiter. The binocular's wide field of view makes it relatively easy to find objects in the night sky. We could easily see three of the giant planet's primary moons (the fourth was behind the planet at the time). We were not able to resolve any surface detail on Jupiter, however. Both Jupiter and the moon were fairly low in the sky, which makes for less than optimum viewing.

The famous Andromeda Galaxy was impressive as seen through the 20x80mm binoculars. Averted vision revealed that it is not just a fuzzy blob, but has limbs that stretch across an expanse of sky. We can hardly wait to get these giant astronomical binoculars to a dark sky site for more deep sky viewing.

The Celestron SkyMaster 20x80 Astronomical Binocular is a well made, impressive instrument and one we can highly recommend. It does not have the light grasp of 25x100 giants, of course, but the smaller size of the 20x80's makes them more versatile and much more user friendly. If you are looking for high quality giant binoculars at a reasonable price, these Celestrons are the way to go.




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