Lunt 7.2mm to 21.5mm zoom


Availability: More on the way

While the 7.2mm to 21.5mm focal length of this Lunt Solar zoom eyepiece specifically complements the Lunt H-alpha refractors for solar observing, it works equally well for nighttime astronomical observing . . .
Our Product #: LS7-21ZE
Lunt Solar Systems Product #: LS7-21ZE

Product Description

The 7.2mm to 21.5mm focal length range of this Lunt Solar zoom eyepiece has been chosen specifically to complement the focal lengths of the various Lunt H-alpha refractors for solar observing. That said, it should also be noted that the eyepiece works equally well for daytime terrestrial observing and nighttime observing with virtually any standard (non-solar) telescope. For these latter situations, the Lunt zoom offers the convenient ability to precisely match the observing magnification to daytime seeing conditions, as well as a virtually infinite number of medium to high power nighttime magnifications in a single reasonably-priced eyepiece.

As with virtually all zooms, the apparent field of view of this Lunt Solar zoom decreases somewhat as the focal length increases. This generally results in a 20% narrower field of view at low powers than you can achieve with similar focal length single magnification eyepieces. This is just the reverse of what most people expect from eyepieces - which is a wider field at lower powers, where you're usually observing larger objects that don't need as much magnification to fit in the eyepiece field. The Lunt Solar zoom's apparent field of view ranges from 53° at the highest power 7.2mm focal length to a 40° field at the lowest power 21.5mm focal length.

Eye relief of the zoom's 7 lens/4 group optical system is specified at 15mm. The eyepiece is fully multicoated. It has a soft rolldown rubber eyecup for eyeglass use. A safety groove cut into its barrel will catch the thumbscrew of your focuser or star diagonal and keep the eyepiece from falling to the ground should the thumbscrew accidentally loosen during use. The power change band on the eyepiece uses a ribbed gripping surface that makes it easy to make small power changes, even in cold weather when wearing gloves or mittens.

Tech Details

Barrel Size 1.25"
Eye Relief 15mm
Field of view 40 @ 21.5mm; 53 @ 7.2mm
Focal Length 7.2-21.5mm
Warranty 1 year


Review by:
Works great. It's much easier to use a variable eyepiece to look at just one object as opposed to when you are looking at everything from planets to star clusters to any other deep sky objects. (Posted on 10/17/2019)
Review by:
I have a Lunt LS60THA solar scope. I took a chance ordering this zoom as I assumed that zoom eyepieces are inferior compared to fixed eyepieces, particularly on internal reflections and color correction. On my solar scope, I find the zoom very useful, as the process of adjusting the etalon and/or tweaking focus is improved greatly if you can easily tinker with magnification at the same time. You can look at the big picture, then inspect details on the prominences, etc. to assist optimization. Also, since I cover myself with a sun shield blanket, it avoids disruption caused by swapping eyepieces or bumping the scope. The magnification range is well matched to the resolution of the scope as at max mag, the resolution is just starting to go a bit soft, and the low magnification is low enough. I see no reflections, and the eye relief is very comfortable. It is better and more convenient than the 12mm TeleVue possl that I was previously using. I've made only a few tests of it for night viewing, and can't make a definitive statement, but it looked good so far.
(Posted on 8/23/2019)
Review by:
I love this eyepiece with my Lunt 60 solar scope, i have tried two others before this one and they didn't cut the mustard, i can't explain why, but this Lunt zoom maintains a nice level of sharpness throughout the zoom range. I found the eye relief to be perfect for me, i also like the feel and the eyecup extends as you rotate it, i have also used it with my other scopes at night and it holds its own there also, i have no idea who makes it and where but who cares it works great. (Posted on 12/18/2018)
Review by:
The Lunt Zoom is my primary outreach eyepiece, and it is fantastic for the job. Mechanically the eyepiece is excellent, it is easy to rotate, and the entire construction of it is solid. This eyepiece makes the switch between magnifications simple, and it runs a handy focal length for most scopes. It isn't (as far as I can tell) parfocal, but I never had to adjust it much. Unlike more budget zoom eyepieces, it holds up well even in faster scopes - it worked well enough in an 8" F/4 (with a coma corrector) and an 80mm F/6 refractor. The eyepiece is more at home in slower scopes, if only because its easier to max out the resolution of your scope without having to use a Barlow. As I build out my travel kit, this eyepiece will find a home - less things to bring along! (Posted on 10/6/2018)
Review by:
(Posted on 8/4/2017)
How do you rate this product? *