Celestron Skymaster Pro 20 x 80 ED Binoculars

Celestron SkyMaster Pro ED binoculars are the ideal choice for amateur astronomers or anyone who observes at great distances. The SkyMaster Pro ED uses superior optics, coatings, internal parts, and housing materials. With large objective lenses, BaK-4 prisms, ED glass, and fully multi-coated optics utilizing Celestron’s proprietary XLT coating technology, the view through a SkyMaster Pro ED sets the standard for astronomy binoculars.

ED Objective Lenses

Extra-Low Dispersion (ED) glass virtually eliminates chromatic aberration, also known as color fringing, a visual phenomenon common in magnified optical systems. SkyMaster Pro ED delivers edge-to-edge sharpness with excellent color correction and razor-sharp images.

Not all ED glass is created equal. Celestron’s high-quality ED glass delivers brighter, sharper images than non-ED binoculars. The difference is especially apparent in low-light conditions.

Celestron SkyMaster Pro ED binoculars are the ideal choice for amateur astronomers or anyone who observes at great distances. The SkyMaster Pro ED uses superior optics, coatings, internal parts, and housing materials. With large objective lenses, BaK-4 prisms, ED glass, and fully multi-coated optics utilizing Celestron’s proprietary XLT coating technology, the view through a SkyMaster Pro ED sets the standard for astronomy binoculars.

ED Objective Lenses

Extra-Low Dispersion (ED) glass virtually eliminates chromatic aberration, also known as color fringing, a visual phenomenon common in magnified optical systems. SkyMaster Pro ED delivers edge-to-edge sharpness with excellent color correction and razor-sharp images.

Not all ED glass is created equal. Celestron’s high-quality ED glass delivers brighter, sharper images than non-ED binoculars. The difference is especially apparent in low-light conditions.

Coatings and Prisms

All of Celestron SkyMaster Pro ED’s lens surfaces are fully multi-coated and feature Celestron’s proprietary XLT optical coating technology. These powerful coatings, similar to the ones you’ll find on our observatory-grade telescopes, decrease reflectivity for higher optical throughput across a broad range of the visible light spectrum. What’s more, the prisms inside the binocular are made of high-quality BaK-4 glass, further boosting light transmission. Working together, the fully multi-coated lenses and BaK-4 prisms deliver more light from your target to your eye for brighter, more detailed views.

Objective Lenses

The 80mm objective lenses offer plenty of light-gathering ability for superior low-light performance. The objective diameter-to-magnification ratio is ideal for scanning the skies, observing the Moon and planets, and exploring all the best deep-sky objects. Celestron SkyMaster Pro ED also makes an excellent choice for long-distance land-based viewing—especially at dawn or dusk.

The Body

Custom-designed rubber armor and a durable chassis protect your SkyMaster Pro ED binocular from damage without weighing you down. Viewing through SkyMaster Pro ED binoculars is comfortable for eyeglass and non-eyeglass wearers alike, thanks to the retractable eyecups and more than 15mm of eye relief. Eyeglass wearers can see the entire field of view while looking through the eyepiece with their glasses by twisting the eyecups down. For those who do not wear eyeglasses, the eyecups position the user’s eye behind the eyepieces at the correct distance for optimal viewing.

Ways to Observe

The Celestron SkyMaster Pro ED binocular is tripod-adaptable. Use the built-in tripod adapter on the balance compensation rail to mount it on any standard photographic tripod or monopod for extended viewing or digiscoping (photography through the eyepiece).

SkyMaster Pro ED’s eyepieces are threaded to accept standard 1.25” astronomical eyepiece filters. Adding the right filter can deliver game-changing views for terrestrial and celestial observing. For terrestrial observation, filters can reduce the brightness of sand, snow, and water. For nighttime viewing, filters can cut glare, minimize eye strain, increase contrast, and even combat the effects of light pollution. Remember, the binocular needs a set of two filters.

GENERAL
Magnification: 20x
Objective Lens Diameter: 80mm (3.15")
Focal Length of Objective Lens: TBD
Angular Field of View: 3.4°
Linear Field of View (@1000 yds) / @1000 m): 178 ft (59 m)
Exit Pupil: 4.0mm (.16")
Eye Relief: 15.4mm (.61")
Close Focus: 98.4 ft (30 m)
Interpupillary Distance (max): 72mm (2.83")
Interpupillary Distance (min): 56mm (2.20")
Diopter Adjustment Range: ±3
Twilight Factor 40
Relative Brightness: 16
Limiting Stellar Magnitude: Ideal: 12.02 | Moderate: 11.02 | Poor: 10.02
Lens Coatings: Fully Multi-Coated - XLT Coatings
Prism Glass (Type): BaK-4
Prism Coatings: N/A
Weight: 123.2 oz (3,492g)
Environmental Protection: Waterproof (IPX7)
Nitrogen Filled: Yes
Tripod Adaptable: Yes
Carrying Case: Deluxe Nylon
Dimensions: 335mm x 230mm x 94mm (13.2" x 9.1" x 3.7")

Included Items:
Binoculars
Objective lens caps
Eyepiece Covers
Rainguard
Neck strap
Lens cloth
Non-Silica Dessicant
Case
Instruction manual

Solar Warning
Never look directly at the Sun with the naked eye or with this optic. Permanent and irreversible eye damage may result.
Never use your optic to project an image of the Sun onto any surface. Internal heat build-up can damage the optic and any accessories attached to it.
Never leave your optic unsupervised. Make sure an adult who is familiar with the correct operating procedures is with your optic at all times, especially when children are present.

Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or sales@rothervalleyoptics.co.uk.

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.

The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

https://www.rothervalleyoptics.co.uk/zygo-tested-refractors.html

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email sales@rothervalleyoptics.co.uk.

Are you interested in this product but would like to speak to someone with some more information? Simply fill in the form below and we will get back to you as soon as we can!

* Name

Please enter your full name

* Telephone Number

Please input your telephone number here

* Model Number

Please enter the model number which is just above

Additional Information

Please include any information here that will help our staff members assist your query

*

Please add the two numbers

SubmitSubmit