Celestron 31mm 2" 82° Luminos


Availability: More on the way

This 31mm 2" Celestron Luminos eyepiece has an immense 82° field of view for low power "picture window" views with 2" focuser Dobsonians and short focal length refractors . . .
Our Product #: CL8231
Celestron Product #: 93435

Product Description

This 2" Celestron 31mm Luminos is an excellent low power eyepiece with an exceptionally wide field of view, one so wide you have to move your head from side to side to see it all. The six-lens design is primarily designed for no-holds-barred low power deep space use. It is particularly well-suited to get the maximum image brightness and field of view out of big Dobsonian scopes, but will work well with any telescope that can use 2" eyepieces, even an f/15 Maksutov.

This eyepiece has a very large 6.9mm exit pupil with an f/4.5 scope, larger than some observers' eyes can dilate. That can effectively waste some of the scope's light gathering capacity, as some of the full light cone will fall on the older observer's iris, rather than entering his or her eye. Even so, some observers willingly trade a little light gathering for the immense field of view of this 82° apparent field eyepiece. This eyepiece very much provides a true "picture window of space" view.

You can use the calculator below to see just how wide the field will be with your particular telescope. For example, it will give you a 2.22° field at 37x with a 10" f/4.5 Dobsonian, more than enough to take in all of the Pleiades at one time. This gives you over eight minutes of uninterrupted observing with such a scope while an object drifts from one side of the eyepiece's flat field to the other. That's plenty of time for multiple observers to look at the same object, or for you to absorb as much detail as possible, before having to reposition the scope.

With a factory-specified eye relief of 27mm, the 31mm Luminos will provide fully unvignetted views for most eyeglass wearers. However, since the 82° field is so wide that you can't see the full field without having to move your head from side to side to take it all in anyway, vignetting in the conventional sense is not a problem in any case.

At 40 ounces, the 2" 31mm Luminos is a very substantial eyepiece. Be sure that your star diagonal is very firmly locked in place on your scope before inserting this eyepiece to avoid the chance of the diagonal swiveling unexpectedly and the eyepiece falling to the ground.

The retractable eyeguard raises by turning the broad rubber grip ring around the eyepiece barrel clockwise and lowers by turning the ring back counterclockwise. The eyeguard mechanism may be a little stiff in operation the first time you raise it.

Tech Details

Barrel Size 2"
Eye Relief 27mm
Field of view 82
Focal Length 31mm
Number of optical elements 6
Weight 40 oz.
Warranty 2 years


Review by:
The Luminos 31mm is as good a wide view/low power EP you can get without breaking the bank. It’s inevitable that the Luminos be compared to the upper echelon occupied by the Naglers and Explore Scientifics, but it’s not fair to do so. While those companies have no peers except to each other (I own an ES 82 30mm) and received the Luminos 31mm during an unexpected acquisition . They’re closer than you would think at the price difference.
The only real criticism I agree with is the EOFB which is distracting at worse, but easily tolerable; make no mistake, it’s there, but not nearly as bad as everybody makes it to be. For me, the $200 I paid was money well-spent, and I will not be parting with it anytime soon. Paying several extra hundreds isnt worth the gains you’d get from the “top” eyepieces. As far as the heaviness of the Luminos 31mm, it’s nothing even a mediocre counterweight system can’t handle. Sure it’s big and heavy, but for my 12.5 f5, it works well, though I don’t think I’d use it for a faster scope. F/5 is probably the minimum you’d get the full potential of the EP, and f/6 and higher would be perfect. I like to resolve double stars and observe planetary nebulas, so I use this mostly.
For the price of the Luminos line, you’re entering premium territory, so maybe it’s a bit more expensive than what most people start out with. However, the build and optical quality make these a serious contender for best- bang -for -the-buck. An added bonus is that because of the sheer size, they’re a top attraction for outreach events or when friends are over.
Highly Recommended (Posted on 8/1/2020)
Review by:
Huge and heavy, but exceptional clarity. FOV is great. (Posted on 10/17/2019)
Review by:
I purchased this and all the other Luminos 31 mm eyepiece because I wanted a full set of para focal eyepieces. I have to say that there is minimal focus adjustments when changing between eyepieces. The view is clear and flat almost to the edges. Since this is a 2" monster of an eyepiece its really heavy, over two pounds so check your rigs balance when using this. (Posted on 10/4/2019)
Review by:
This thing is Super HUGE!!! like a grenade its crazy!!!! I havent tested it out yet but its pretty heavy and HUGE!!!!
You can kill someone with this if needed. For the price I am sure thats its going to be great. (Posted on 12/29/2018)
Review by:
Nice eyepiece. Sharp images and beautiful wide field views. (Posted on 12/9/2018)
Review by:
This maligned ocular does have some positive traits: sharp and clear in the center half, generous eye relief, and relatively light weight in its class once you remove the obscenely large metal housing. I found this to be a worthy upgrade over the standard 30mm 68° erfle type eyepiece. HOWEVER, the severe EFoB and astigmatic mush in the outer field is distracting, and superior options like 30 ES82 and 35 Pan are - in my opinion - worth the investment. At low powers I like to look around the view, but 31 Luminos views are only satisfactory if I keep my eye aimed at the center. (Posted on 10/26/2018)
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