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Meade 56mm Plossl

Posted by Ed Moreno   01/04/2006 13:30:PM

For faster scopes, a 32mm eyepiece is all you need to maximize your field of view, but for longer focal lengths, such as with Maks and SCTs, getting a the largest true field of view with GOOD QUALITY across the field can be a very EXPENSIVE challenge.

Many years ago, I bought a 35mm Panoptic, and it has been my workhorse eyepiece, being used in just about every scope I own. The 35mm Panoptic is priced well below the 31mm Nagler and 41mm Panoptic, and in terms of actual field, it gives up VERY little to either, and the performance is overall superb.

But there have been times where I could have used a bit of extra field. It was just very hard for me to justify the BIG dollars that it would take to improve on the 35mm Panoptic. I did try some inexpensive 40mm eyepieces, but found the edge of field performance to be less than great, and for 35mm Panoptic owners, well, you get spoiled.

This is my second 56mm Meade Plossl. I had one previously and wasn’t using it much after getting the 35mm Panoptic, so I sold it. Well, with a recent purchase of a Celestron CGE 1400 setup, the need to squeeze a bit more into the field became somewhat more imperative. While the 35mm Panoptic worked for me well in the 2800mm focal length NexStar 11, suddenly I found myself running out of space to cram large clusters into when using the 35mm Panoptic with the 3910mm (Stated, but I believe it is actually longer than this) focal length of the C14.

Some of the larger clusters like M37 become so large, that they overrun a 30 arc-minute field. In fact, in my newly acquired C14, M37 totally fills the 35mm Panoptic’s field of view. Almost all of the Messier clusters fit in the field, but BARELY. You can’t “Frame” some of these clusters easily though. By that I mean that it looks like you are just looking at a field full of stars. Many clusters change character when you put them in a field surrounded by contrasting background stars. So there are times when I want a bit more field of view. Enter the Meade 56mm Plossl.

Using the Meade 56mm, I get about seven or eight more arc-minutes of true field in the big SCT. Now this doesn’t sound like much of an improvement, but I find that this field is JUST enough to make enough difference to make the purchase price worth it. I didn’t feel that the cost of the 41mm Panoptic would be very easy to justify though, but the 56mm Plossl is by comparison a dirt cheap eyepiece.

So, is it any good?

Well, in fact, I find it to be a really fine eyepiece. Mine is the older style without the eye-guard. It is the second one I have owned, and performed identically to the first (Also an older one without the eye-guard).

It is hard to compare contrast to the 35mm Panoptic, because the lower power opens up so much more sky that background glow becomes a larger factor. If I compare them side by side, I can detect fainter stars in the Panoptic, but again, I think that this is very much a function of decreased background glow. I see the same effect when going from the 35mm Panoptic to the 22mm Nagler. Increases in magnification will pop in additional stars. So while I am not able to make an exact comparison (and that wasn’t really the intention), my observations indicate that the performance of the 56mm is at least as good as all of the inexpensive and mid-priced 40mm eyepieces I have used, and in fact, I would say better than most.

The field is quite sharp out to within a very few arc-minutes of the edge of field. Only in the last couple minutes toward the edge do I notice any optical degradation. This is VERY minor. In fact, I used the 56mm in my f/5.7, 140mm Vixen refractor (Totally on a whim, because this combination results in a 14.2x magnification and a 3.5 degree field but with a 10mm exit pupil!!!) Still, I was quite surprised to see that once again, the field seemed fairly sharp until the last few degrees before the edge.

Now one of the things that is important to me in terms of having a wide true field is to also have a sharp field. Having owned several other 2” low and mid-priced eyepieces longer than 32mm in focal length, only the Panoptic so far has given me the kind of across the field sharpness that really pleases me. I consider the 56mm to be the second best in this regard of the other 2” eyepieces that I have used past 32mm focal length, but being second to the 35mm Panoptic is not a bad thing. When I pull out the 35mm and put in the 56, I am aware of the difference in the apparent field field of view, but I don't feel like I am giving up any quality to get a bigger true field. And that was the whole idea… Get those extra few arc-minutes of field without spending lots of money.

There is one characteristic of this eyepiece that some people might not like. Eye relief is VERY long. You have to hold your head back away from the eyepiece quite far to see the full field. You have to back away o far in fact, that you see around the outside of the eyepiece with your peripheral vision. This lets ambient light enters, so if you observe in an environment with high ambient light (My backyard is not all that dark) this could be distracting.

Now I am not even remotely suggesting that you can match the performance of the most expensive premium wide-angle eyepieces with the Meade 56mm, but I am suggesting that given a field of “X” degrees, there is “Y” amount to see, and the 56mm seems capable of showing just as much, just about as sharply, for a quarter of the price of a premium, and half the price of a mid-priced wide-field eyepiece.

These eyepieces have been greatly reduced in the new selling price lately, and frankly, after trying a few other mid-priced 32mm+ wide-angle eyepieces and being less than satisfied with their edge performance, I think the Meade 56mm presents a VERY attractive alternative if your goal is to get the biggest field from a slower scope like an SCT or Mak Cass. SO, if biggest field/exit pupil in your long focal length scope is the REAL goal, the Meade 56mm eyepiece is a VERY good way to get there. Highly recommended…