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Antares 127mm Semi ED vs Meade AR 5

A Tale of Two Achromats
Antares 127mm Semi ED vs. Meade AR 5
A Tale of Two Achromats
Gerry Smerchanski

Here are the two scopes under review. (I left cellophane around the Meade tube under the mounting rings, so don't be concerned about the finish in these photos.) Camera perspective might fool you into thinking the Meade tube is larger but they are very similar in size and length. The dew shields are different with the Meade shield being larger in diameter but shorter in length.

I recently had an opportunity to compare two scopes from two companies that have been much talked about on Cloudy Nights forums. These are the Meade AR5 achromat and the new Antares 127mm semi-ED refractor. It seems that in these forum discussions there is a tacitly assumed 'pecking order' for the quality of scopes and I was curious to see if these two examples would support those assumptions.

I have owned the Meade for about two years and have just recently acquired the Antares scope. I will restrict my comments to the period of time (several nights) when I had them for side-by-side comparison as I have found that my ability to do comparisons outside a brief time window are subject to too many variables and are neither meaningful nor repeatable observations. Despite all the talk comparing these scopes, I have not seen a review where the two are reviewed side-by-side.

To add to the description of this comparison I would like to say that I have not owned many refractors (less than a dozen) in my forty odd years of observing, but I have spent some time looking at demanding targets such as the planet Mars through some very capable refractors including an Astro-Physics 130mm and Takahashi 102, so I am acquainted with what is possible with the refractor format. My currently preferred planetary scope is an Intes 150mm Maksutov-Newtonian.

The scope specifications for this comparison:

Meade AR5 (aka 5"LXD55 achromat)
Objective: 127 mm
Focal length: 1180 mm
Focal ratio: f/9.29 listed as 9.3
Weight including dewshield, mounting rings, and finder: 14.8 lbs (6.7 kg)

Antares Semi-ED refractor
Objective: 127 mm
Focal length: 1200 mm
Focal ratio: f/9.44 listed as 9.4
Weight including dewshield, mounting rings, and finder: 16.3 lbs (7.4 kg)

So as you can see from the specs, these scopes are quite similar and would be directed towards the same buyers and uses and are a natural for a comparison review. A little bit of history about the particular scopes I compared: Both were purchased used. I have owned the Meade for over 2 years. The Antares was obtained fall of 2005. The previous owner of the Meade said that it was sent back to the factory to have its objective replaced. I am uncertain now if that was due to damage in shipping or poor performance but I was encouraged to hear that it was a replacement objective as I have found through personal experience and that of others that replacement objectives are usually quite good. And yes, I am aware of other instances suggesting the contrary.
(see Ed Ting's article at http://www.scopereviews.com/page1b.html )
I have used the AR5 for about 2 years and compared it to other scopes and found it to be a very competent performer. It's just what you'd expect from a very good two element achromat.

The Antares scope that I purchased seems to be bit out of the normal production as well in that it doesn't bear the new Antares logo and has the plastic focusing knobs. From the readings I have done on the Cloudy Nights' forum, I believe that I might have one of the earlier or prototype versions rather than the current production run. So it can rightfully be claimed that neither of these scopes might truly represent the current model lines except in a general case. But given the variations within these mass produced scopes this comparison might still be as valid as any other. Enough caveats, on to the comparison.

Physical comparison
As the pictures show, these two scopes have much in common. Both use identical finders and very similar finder brackets. Both use similar looking and feeling rack and pinion focusers with identical looking knobs. Both use tubes that are very similar and within millimeters of being the same length. (It's tough to be exact here as the flange behind the lens cell can mislead one in determining actual length.) Both tubes incorporate a series of three concentric baffles placed along the length of the tube. The mounting rings fit either tube equally well. The Meade rings are noticeably lighter and use aluminum thumbscrews while the Antares thumbscrews are steel. The aluminum thumbscrews are a treat to use but durability might not be similar to the steel units used on the Antares. The rings, the gusset ring for the lens cell and the focuser assembly of the Meade all have a dark grey colour and a smooth finish while the Antares has a more traditional Ôhammertone' look to its fittings.

The Meade AR 5 (on the left) secures finder with hex screws. Antares uses more convenient thumbscrews.

Where the two scopes have some differences is up front at the objectives. The cell and dewshield of the Meade is noticeably larger in diameter. The Meade cell is adjustable with two sets of screws in a push/pull arrangement and this might be the reason for the larger cell. The Antares cell is not adjustable and is made of non metallic material.

The Antares dewshield is considerably longer than the Meade unit which looks odd in being greater in diameter than length. I think the Antares dewshield is more effective in its appointed task of blocking stray light.

Surprisingly given the similarities and slightly larger proportions on the front end of the Meade, the Antares has a noticeable heft to it. I weighed them and found the Antares to be about 1.5 lbs heavier with about a third of that difference coming from the mounting rings. (Antares at 16.3 lbs vs. Meade at 14.8 lbs) Perhaps that is a clue that slightly different fittings are responsible for the extra weight. When the appearance of the glass and coatings comes up, there are some strange results. The picture shows the Meade objective (on the left) with a pronounced green tint and a dimmer reflection. And yet when I look at the two visually, they are much closer in colour and reflectance. That is a curious result that may just be an artifact of the camera or angle.

Some Preliminary checks

There has been some discussion as to whether some telescopes are achieving better optical performance by restricting the full aperture of the scope with Ôpoorly' placed baffles. A quick check with a Cheshire eyepiece shows that the full objective is visible from a fully racked focuser so this should not be an issue with either of these scopes.

When I first obtained the Meade I found that the focuser was not pointed towards the centre of the objective and some adjustments on how the focuser attaches to the tube was in order. A check of the Antares using a laser collimator showed that it too was not quite pointed directly at the objective's centre. Star tests would still be required to confirm the optical behaviour of these scopes, but this test does help to sort out where some of problems might be found if poor star test is found. If collimation issues were found the Meade, with its collimation adjustments, would be much easier to correct than this early Antares. (Note: later Antares units have adjustable cells)

Here the alignment of the Antares focuser is being checked by projecting the laser onto a mask that has the centre marked with a dimple.

Optical comparison

This comparison was done over several nights in the fall 2005. The scopes were equally cooled down, and to control for variances in diagonals, the same TeleVue Everbrite 2" diagonal was used on both. Since the focal length is so similar, the same eyepieces can be used in both cases without introducing an unfair advantage to either scope. A few defocused star images showed that there were no serious collimation issues or other optical defects, with either scope.

When refractors are compared, the big issue is usually chromatic aberration (CA). So the first target of the night was Vega. Both scopes showed a nice white star and some purple fringing. The colour of the fringe was slightly different in each case, but the amount of purple was less in the Meade. The Airy disc however, was tighter and better defined in the Antares. This was a bit curious so I repeatedly switched back and forth to make sure of this. The result stands, and given the seeing at the time, there was a hint of the first diffraction ring with the Antares that wasn't there with the Meade. But the Meade consistently showed less purple fringing. How to rate this result depends on what bothers you most. The fringing issue is affected by the observer's particular sensitivity to various wavelengths. Neither scope showed objectionable amounts of "Purple haze" compared to other achromats I have examined.

The second target was the "double-double", epsilon Lyra. Both were able to split the close doubles but the view was more pleasing in the Antares with its better defined Airy discs.

While in the vicinity, I looked at the Ring Nebula, M57. Both scopes showed a similar view. Each time I thought I could see a more defined image or a darker backround, I returned to the other scope and dismissed my suspected difference. There was nothing to distinguish the scopes here. The same was true for images of M13 in Hercules. Whichever scope that I was using at the moment seemed superior to the view just before. Both scopes were able to just begin to resolve the cluster with neither scope showing any distinct advantage after several repeated trails.

Up to this point, all observing was done with 1.25" eyepieces. I wanted to see how well each scope presented the max field of view, so the scopes were turned on to the Pleiades and a 2 inch 32 mm Konig and a 2 inch 52mm Erfle were used to frame the open cluster. While both scopes showed excellent sharp star images on axis, the Antares showed a sharper field toward the edge. This was especially noticeable with the Konig eyepiece which usually doesn't mind focal lengths larger than f/8. Konig eyepieces are noted for being very sharp on axis and having less than perfect edge of field especially in faster focal length scopes. I find this characteristic is useful in evaluating scope performance, but one must keep in mind that this result in not universally generalize-able. I have seen certain scope/eyepiece combinations that work well, while that same eyepiece in another scope can be quite disappointing. But these are the eyepieces that I have grown to like and use so they are what will arbitrate this part of the test. Since one of the intended uses of this scope for me is for the wide field of views, this was a significant finding for me. I should confess that I get greatly distracted by fuzzy images near the edge of the field and that this issue might not be quite so important for others.

By this point in the evening, Mars was high enough to provide another type of test object. The views, given the conditions, were a bit less than optimal. I have been viewing and sketching Mars for several months with a 150mm Maksutov Newtonian and the view through these achromats, with their inherent chromatic aberration and less resolution due to smaller aperture, required me to make an adjustment in my expectations. Both scopes were able to accommodate my binoviewer and Barlow combination that I like for planetary viewing. That is a fair bit of weight to put on these inexpensive focusers but I didn't notice any disturbances in the image due to the focusers unable to hold alignment.

Mars was also the target for the second night of testing and while the views were very close, I preferred the view through the Antares. There seemed to be more contrast in the view in the Antares along with a slightly greater degree of sharpness. But if I hadn't had the scopes side-by-side, I would likely have been equally pleased with the views through either one of them. Leaving the scopes for more than a minute or so would make me doubt which had the superior image. It was only with quick side-by-side looks that the differences could be detected.


It was obvious by this point that the performance of the two scopes was very similar. Both had no glaring (no pun intended) faults. In fact, I tried to make the tests somewhat "double blind" by coming back to the set up after a period of time and forgetting/disregarding which scope I was using, and I would have doubts as to which one I was looking through in some tests; the exceptions being the immediate side-by-side comparisons on Mars and the definite long term difference for the 2" eyepiece edge of the field of view which seemed better managed in the Antares. The somewhat better defined Airy disc of the Antares might have played a larger factor in this test if the seeing conditions would have allowed, but alas, no testing can be complete in all aspects.

I would have liked to continue this close comparison, but there were several buyers waiting for my decision and one buyer was anxious to get observing on his own. In the end, I decided to keep the Antares due to its marginal superiority in several issues that I regard as important. The Antares proved to be at least as capable as the Meade. But I would have liked to have kept a scope with an adjustable lens cell. (I have read that later Antares do come with adjustable cells.) But really these scopes could justifiably be considered "Twin sons of different mothers". I would have very much liked to do direct comparisons of the star test procedure and to evaluate their abilities to render images of the moon. As the new owner of the Meade lives an hour and half down the road, the option of future tests remains a possibility.


So now that I am living with the Antares "semi ED" 127mm, I want to say something about that unfortunate name which leads one to expect performance superior to regular achromatic refractors. In all of my testing there was nothing to suggest that this scope was performing on a level over and above that of a very good achromat of that focal ratio. The amount of chromatic aberration, while very controlled, was still evident and no other aspect of its performance suggested that a new category of performance requiring a new classification was in order. So let us not give the marketing mavens any more encouragement by allowing such terms into our vocabulary. Nothing but irrelevant debates, false expectations, and disillusionment will be the result. Instead, let us appreciate that we now have wide range of refractors that can deliver excellent images of the sky without costing exorbitant amounts of money. These are good times to be looking up.

  • Jim78154 likes this


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