Explore Scientific 4.7mm 82° field argon-purged waterproof 1.25" eyepiece


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This 4.7mm Explore Scientific 82° field argon-purged waterproof eyepiece is an excellent very high power, very wide field waterproof eyepiece for resolving globular clusters and closely-spaced binary stars.
Our Product #: ES8204A
Explore Scientific Product #: EPWP8247-01

Product Description

This 82° 4.7mm Explore Scientific is an excellent short focal length/ultra wide field eyepiece with an unusual benefit. It is O-ring sealed and argon-purged to be 100% waterproof. This prevents internal fogging in the eyepiece; keeps the interior dust-and fungus-free; and makes it easier to clean, as there is no risk of excess cleaning solution getting trapped between the lenses.

The latest computer design programs have been used to optimize its performance. Its seven element/four group design uses low dispersion and high refractive index lenses and full multicoatings for high contrast, high resolution, and flat field images across a very wide 82° field of view. The lens edges have been blackened to improve contrast.

The 4.7mm 82° Explore Scientific works with any telescope from a fast focal ratio reflector to a long focal length refractor or Maksutov. It's particularly good with Dobsonians and fast focal ratio refractors, providing high magnification with a very wide field of view for observing smaller globular clusters and compact nebulas.

At 14mm, the eye relief is surprisingly good for such a short focal length eyepiece, although eyeglass wearers will still see a somewhat vignetted image. This is not as much a problem as you might think, as the 82° field of view is so wide that even non-eyeglass wearers have trouble seeing the whole field at once. This is an eyepiece that shows you a "picture window view" of space for a true full-immersion observing experience. With its unconstricted view, your eye relaxes, allowing you to easily use the "averted vision" technique to study faint details across a huge field of view.

You can use the calculator in the "formula" tab above to see just how wide the field will be with your particular telescope. For example, it will give you a 0.54° field (slightly wider than the full Moon) at 152x with a 4" f/7 refractor like the Explore Scientific 102mm triplet apo refractor.

The eyepiece has a soft fold-down rubber eyecup and comes with dust covers for both ends of the eyepiece.

This individually serial numbered Explore Scientific eyepiece is backed by a limited one year warranty, which will be extended to an Explore Scientific transferable lifetime limited warranty when its warranty card is registered with Explore Scientific within 60 days of purchase.  Here's a link to the full details on this unique transferable lifetime warranty.

Tech Details

Barrel Size 1.25"
Eye Relief 14mm
Field of view 82
Focal Length 4.7mm
Number of optical elements 7
Weight 7.5 oz.
Warranty 1 year, extendable to lifetime


Review by:
Good high power eyepiece that offers most of the performance of the Televue Nagler series, but at a more affordable price. Well corrected with good light throughput. The eye relief is a bit tight (tighter than the ES 6.7mm 82deg) but still pretty comfortable, particularly for non-eyeglass wearers. (Posted on 10/28/2019)
Review by:
A great medium high to high power eyepiece dith a wide FOV which the bonus of more area to view at high power. This eyepiece gets used a lot. (Posted on 10/25/2019)
Review by:
The 4.7 is my latest addition in the ES 82 line. I use these in all of my scopes which range from a Meade ETX 80 refractor, ETX 125 Mak, Orion XT8 Dob , Apertura AD12 Dob. Great images in all of my scopes. I also have the ES 82 14, 8.8 and 6.7. (Posted on 10/25/2019)
Review by:
I use this eyepiece in my 12" F5 telescope, and it does well with planetary and Pne observations. The only downside to this eyepiece is the short eye relief. Its quoted at 14.7mm, but the lens is set back into the eyecup and it takes getting your eye up into the eyepiece to see the full field. (Posted on 9/10/2019)
Review by:
I used this all last summer to observe planets. With my 12.5" dob (324x), I didn't need to bump the tube as often, because of the wider field of view. Good for double stars also. (Posted on 1/4/2019)
Review by:
Very nice eyepiece for the price (Posted on 1/1/2019)
Review by:
Very nice high power eyepiece. I've had some great views of the planets and planetary nebulae with this eyepiece. I bought at the intro price of $100, at $160 still a pretty good deal. (Posted on 12/28/2018)
Review by:
This is my high power EP for my refractors. Gives me great views of the moon and planets alone and with a barlow. (Posted on 11/28/2018)
Review by:
I use this in my AT 72ED the most and really like it in that scope. I think it is a great value. Solid build, perfect size, great eye relief. (Posted on 11/3/2018)
Review by:
This 4.7mm ES82 is a really fine high power eyepiece and one of the strongest in the ES82 series. It's effective in larger fast Dobs and in refractors. I saw NO shortcomings in mine. (Posted on 10/30/2018)
Review by:
The combination of short eye relief and recessed eye lens made this something of a chore to look through. To get the full field I had to mash my eyelashes against the housing, which was not a nice feeling, and slight touches at high power can shake the image on lighter mounts. I also saw internal reflections while viewing planets, so this was not a satisfactory Lunar/planetary ocular for me. That said, it is very small and lightweight with a wide clean field that should be great on globular clusters and the like for anyone who doesn't mind very tight ER. (Posted on 10/26/2018)
Review by:
This eyepiece is well constructed. The optical quality and eye-relief is quite amazing. A must have at every public outreach whenever I host one. (Posted on 10/16/2018)
Review by:
I have both the 4.7 Explore Scientific and the 5mm Nagler Type 6 (which this eyepiece directly competes with) in my eyepiece case, and took a few minutes to compare them side by side the other night. Eye relief is somewhat tight but 100% usable on both without being uncomfortable, though it feels slightly tighter to me on the Explore Scientific, even though it is published as 14mm (vs 12mm on the Nagler Type 6 line of eyepieces). Not sure why, but maybe the combination of it's slightly more recessed eye-lens element and my deep-set eyes. YMMV. I observe without glasses however, so if you wear glasses when observing this will not work well for you.

I am definitely keeping both, with the 5mm Nagler seeing frequent use in the 85mm f7 grab-and-go refractor (TV-85) and the 4.7mm for max power in the 100MM f9 (Skywatcher 100ED).

Optically they are close. Explore Scientific did a great job with their line of 82 degree eyepieces, and the 4.7mm is one of the stand outs in this this line. At less than half the price of the 5mm Nagler it's hard to go wrong. (Posted on 10/15/2018)
Review by:
Really good high power eyepiece, Good eye relief. Works very well with my Tak Sky 90. (Posted on 10/6/2018)
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