Meade 36mm QX

Meade 36mm QX

Recently, I bought a 5" Maksutov telescope to use as a grab-n-go scope. One of the benefits of a smaller telescope is the correspondingly smaller focal length and larger field of view. So, I began to search for a way to use it as a wide field telescope. First, I bought a .63X focal reducer thinking that I'd reduce the focal length so I wouldn't have to use unwieldy 2" eyepieces to get down to low magnifications. Big mistake. The focal reducer brought the focal plane in so far that most of my eyepieces couldn't even reach focus and the ones that did has visible distortion in the outer 25% of the field of view. In desperation, I returned the focal reducer and swapped it for a Meade 36mm QX eyepiece with the dreaded 2" barrel. The recently introduced QX eyepieces are 5 element designs related to Erfles that are offered at extremely attractive prices ($99 for the 36mm). So, I figured that if I didn't like it, then I didn't stand to lose too much.

First Impressions

	Specifications Focal length: 36 mm Apparent field of view: 70 degrees Number of elements: 5 Optical design: modified Erfle Manufacturer: Meade Cost: $99, new
	Advantages Very wide field of view Sharp optics Almost no chromatic abberations High contrast Good light throughput Neutral color balance No internal reflection problems noted Low cost ($99) High build quality Large eye lens Comfortable to use Foldable rubber eyecup
	Disadvantages Heavy - may unacceptably disrupt the balance of some telescope mounts 2" barrel may not work with some telescopes The focal plane is very close to the outside surface of the field lens making any dust present on the surface of the lens highly noticeable Not quite as much eye relief as expected

My initial physical impressions of the eyepiece were quite promising. The QX series, like the other Japanese made Series 4000 eyepieces are of a very high build quality with nice blackened anodized barrels and shimmering green blue multi coatings. This eyepiece really has some weight to it. There are no parts that ratte or don't fit tightly and precisely. This eyepiece feels like a quality optic and seems like it should cost two or three times its actual ($99) cost. The only apparent area where I can discern a difference in build quality in the QX series verses a premium eyepiece such as the Televues is in the labels, which are printed (nicely) instead of engraved, which would be more durable.

First Views

Given the high build quality of the eyepiece, I wasn't sure what to expect before my first look through the eyepiece. In some respects, I was sure that the quality of the optics couldn't be that good considering the price. I was wrong. My first glimpses through the QX were enough to win me over entirely to 2" eyepieces and to the QX eyepieces in particular. The QX, with its bright, sharp, and wide field of view very quickly became my favorite eyepiece.

Field of View

The nice wide 70 degree apparent field of view provides a comfortable porthole into the view as opposed to the claustrophobic feel of most 1.25" barrel eyepieces. In addition, I found that the true field of view in this eyepiece is about as wide as I would ever want for astronomical objects. In my 5" F/10 Maksutov, the field of view is about a degree and a half which is about 3 moon diameters. Even large nebulas like the Helix are only about half a degree across. Only a few objects like the Andromeda galaxy and the Veil Nebula are large enough to surpass the field of view. I've tried longer focal length eyepieces such as the Meade 56mm Plossl, but there was little difference in the true field of view due to the smaller apparent fields of view of these longer focal length eyepieces. For wide fields of view, it's hard to do much better than this eyepiece.

	Meade 36mm QX Multicoatings

Optical Quality

I was expecting the outer part of the field of view to be plagued by aberations, both spherical and chromatic, considering its low price. I was pleasantly surprized on both counts. In terms of sharpness, except for the very outer 5% or so, the outer portion of the field of view is quite good. There is a noticable amount of light falloff at the very edge, but it's not objectionable and can't really be seen except during daytime use. In addition, the edge of the field of view is defined by a nice, sharp field stop, which I like. I can't stand eyepieces with fuzzy field stops. They just give an impression of imprecision, which the QX does not have in any way. When viewing very bright objects such as the full moon, you might expect to see noticable chromatic abberations from the QX, but the view is surprizingly color free. I've looked at planets such as Jupiter and Mars with this eyepiece and found that the view is so sharp that even though the images of planets are tiny, I can still see a bit of detail

	Meade 36mm QX with Folding Eyecup

Ease of Use

I have a 12mm Intes eyepiece with a 1.25" barrel that is also an Erfle design. By holding the Intes up to one eye and the QX up to the other, I found that they have a nearly identical 70 degree field of view. However, the experience of using the QX is much more enjoyable. The nice wide eye lens of the QX is very forgiving of eye placement and the larger size means that it has a much longer eye relief than a comparable 1.25" barrel eyepiece. Overall, I would have to say that the eye relief of the QX is a little bit shorter than I had expected. You still need to get your eye pretty close to the eyepiece to take in the entire field of view. This may be due to the fact that the eye lens is recessed about 10mm from the top of the barrel. On the other hand, the recessed position of the eye lens allows it to stay clear of your eyelashes and helps it to remain nice and clean. I tend to like to use the eyepiece with the rubber eyecup folded down because it's easier to get close to the eyepiece and take in the whole field of view at once.

	Meade 36mm QX Eye Lens

Focal Plane Location

One other practical issue that impacts the ease of use of this eyepiece is the location of the focal plane of the eyepiece with respect to the lens elements. The focal plane seems to lie very close to the outside surface of the field lens. This means that any dust that may be present on the exterior surface of the field lens will be be almost precisely in focus and will therefore be quite evident. As a comparison, with the 14mm Meade UWA, the focal plane seems to actually be located inside of the eyepiece. This is much preferable because it means that any dust present on the outside surface of the field lens will be significantly out of focus and therefore almost invisible. As a result of the location of the focal plane of the 36mm QX, the eypiece must be kept super clean for optimum performance.

2" Barrel Size

Inspecting the other end of the eyepiece, you'll find the field lens takes up almost the entire width of the sizeable 2" barrel. In fact, if you look through the eyepiece and press a fingernail past the edge of the bottom of the barrel, you'll see that the edge of the barrel is right at the field stop of the lens. So, the eyepiece is taking in a full 2" circle of the focal plane. The 2" barrel is no gimmick. Every millimiter is being put to good use.

	Meade 36mm QX Size Comparison

Conclusions

By this point, it's probably apparent that I'm quite a fan of this eyepiece. For comparison, I have owned a 32mm Televue Plossl and I have looked through a few Radians and Panoptics. I have not had a chance to compare the QX side by side with these other eyepieces although I have compared them side by side with a variety of other 1.25" eyepieces. The QX remains my favorite eyepiece and has won me over so much that I am in the process of replacing all my 1.25" barrel eyepieces with 2" barrel eyepieces. Especially considering the price, you just can't go wrong with this eyepiece.