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APO-Wars: The (Meade) Empire Strikes Back

Posted by Alec Hitchman   02/02/2007 12:00AM

APO-Wars:  The (Meade) Empire Strikes Back
Just over a year ago, Mighty Meade made an announcement: they were preparing to release a new, low cost, triplet apochromat design. A number of questions were immediately raised in forums and blogs across the web: Would Meade’s entry into the low-cost APO field rout the established players in the field? Are three pieces of air spaced glass in a mass-produced objective better than two?

While few details were forthcoming from Meade (they were apparently busy trying to get the telescopes out the door), with the initial Series 5000 triplets finally shipping in early 2007, we could finally see if the Empire’s apochromat has what it takes to crush the Rebellion.

Design Specifics

Available in 80 and 127mm objective diameters, the Series 5000 triplet apochromats boast fairly short focal ratios, f/6 (480mm) and f/7.5 (953mm) respectively. With machined aluminum Crayford focuser, retractable dewshield, screw-on lens cap, and collimatible objective cell, the Series 5000 apochromats have what can be considered these days as a standard feature set.

The air-spaced triplet objective utilizes FCD1 extremely low dispersion glass. This Hoya glass is equivalent to Ohara FPL-51, which provides less dispersion (and higher refractive index) than the higher-end FPL-53 glass. Not surprisingly, FCD1 is also cheaper than FPL-53. While I am no optician, it seems as if Meade is banking on a triplet that uses relatively inexpensive glass to provide color correction that meets, or exceeds, the color correction of a typical fluorite-based doublet.

First Impressions

After only thirteen short months, Meade finally drop-shipped my 80mm version of this new triplet apochromat. The address Meade had on file was my old address, but an understanding occupant at the old house soon had the telescope in my hands.



The telescope is certainly handsome, with all-metal construction, and striking black and blue finish, with blue and silver trim. The overall diameter of the Meade scope is large for an 80mm telescope, and the Meade seems quite a bit bigger than my trusty APOgrade Zenithstar 80mm fluorite doublet from William Optics. The Zenithstar is a bit heavier, though.



The mechanical quality of the Meade could be rated as very good, but my Zenithstar just “feels” better. I really wish that the Meade came with a dual-speed focuser standard. While the Meade has a shorter focal ratio than my Zenithstar (f/6 vs. f/6.9), I’m not sure that I would like using the Meade for astrophotography, simply because the single-speed focuser could prove to be problematic. I really like the threaded lens cover…nice touch, Meade.

A stranger design feature is the implementation of “rotatability”. Most apochromats these days come equipped with rotatable focusers, primarily as a nod to the astrophotographers with whom these telescopes are so popular. Just to be different, Meade implemented this feature by attaching the ubiquitous dovetail mounting bracket to a ring that sits in a finely machined slot around the circumference of the optical tube assembly. Therefore, the focuser itself does not rotate, but rather the entire optical tube rotates. This design makes it impossible to use the rotation feature in conjunction with mounting rings; to rotate, you must mount the telescope using the included dovetail bracket.



The objective cell is massive, and looks over-engineered when compared to the Zenithstar cell. Behind the glass, the interior of the OTA appears to be baffled well. The multi-coatings on the Meade objective appear to reflect noticeably more light than the Zenithstar objective, at all incidence angles. William Optics’ STM coatings appear to have a clear advantage here.



First Light

The notorious Northwest winter weather gave me a break, and clear skies were forecast a day or two after the arrival of the Meade. Despite the full moon, I mounted the Meade next to my Zenithstar 80mm fluorite refractor, and took a quick peek. As the telescopes have significantly different focal lengths (Meade=480mm, Zenithstar=555mm), comparisons at nearly identical magnifications proved to be impossible. Even so, brief comparisons were made between the scopes, using a GSO 30mm Superview 2” eyepiece, as well as Orion Stratus 2” eyepieces in 8 and 3.5mm focal lengths.

Trapezium

Using the GSO 30mm Superview provided 18.5x with the ZS80FD, and 16x with the Meade. At this magnification, the Trapezium could not be resolved to my eye.
Due to the full moon, little of the associated M42 nebulosity was apparent through either scope.

Moving to the 8mm Stratus, the magnifications of 69x (ZS80FD) and 60x (Meade) were sufficient to resolve the four primary components of the Trapezium. Both scopes showed more of the nebulosity immediately surrounding the Trapezium complex. Stars in both scopes appear to be perfect pinpoints across the majority of either field. An initial perception of slightly greater contrast through the ZS80FD was first detected using this eyepiece.

With the 3.5mm Stratus, magnifications reached 159x with the Zenithstar, and 137x with the Meade triplet. In either scope, the Trapezium was nicely framed in the central portions of the M42 nebulosity that surround the famous “Fishes Mouth”. Seeing effects were perhaps to blame for a slightly softer focus with the ZS80FD, although this scope still showed greater contrast. Some mottling across the nebulosity was observed, though the mottling was more pronounced in the Meade apochromat.

Full Moon

Turning my attention to the object dominating the sky this frigid February evening, it was time to check both scopes for baffling and false color.

No matter which of the three eyepieces was used, the Zenithstar did not appear to have as effective baffling as the Meade scope. With the moon just outside of the field of view of the Zenithstar, the background sky was bright grey, with bright ghosting providing a distinct cue to the location of the lunar limb just outside of the field of view.

The Meade baffling was more effective, but not what I would consider perfect. Musing upon these baffling results (no pun intended), and thinking back to the apparent higher contrast with the Zenithstar, I began to suspect that the higher contrast with the Zenithstar may have been a result of the slightly higher magnifications delivered by the William Optics’ telescope when used with each eyepiece.

As for false color on the limb of the full moon, both scopes showed essentially none to this observer’s eye. If I had to make a choice between the ZS80FD and the Meade, I would have to give a slight edge to the ZS80FD.

Saturn

Rounding out the brief series of comparative tests, the scopes were slewed for a look at that jewel of the Sun’s family, Saturn.

The view with the 8mm Stratus demonstrated why apochromatic refractors are so popular. Even with the full moon, the background was dark enough through both scopes to provide a pleasing contrast with the yellowish orb of Saturn. No differences in contrast between scopes was evident here. Titan was visible to the east of the planet, and slight hints of detail were visible on the planetary disk in both scopes.

As Saturn was only about 23° above the horizon, the 3.5mm Stratus did not provide additional detail, only a slight blurring of the more magnified planet. Cassini’s Division was not obvious through either scope, at any of the magnifications used.

Conclusion

I was somewhat skeptical of the Meade Series 5000 triplet refractors, but this example of the 80mm variety was a pleasant surprise. While certain obvious concessions have been made (single speed focuser, no storage case) to keep prices down, other features (screw-on lens cap, collimatible lens cell) seem to run contrary to large volume cost controls.

To speak briefly on other points: the baffling of the Meade scope seems to be better than the baffling of the ZS80FD, but the multi-coatings on the Zenithstar objective look superior. Overall, the fit and finish of the Meade is a step above their usual offerings, and do not disappoint at this price point. While high-power star tests could not be performed for this brief review, the triplet seemed to hold it’s own against the fluorite doublet on the William Optics’ apochromat.

Overall, the only big drawbacks to the Meade scope are the lack of a dual-speed focuser, and the strange “rotating tube” design which limits use of the scope with mounting rings. These issues aside, the availability of a solidly built triplet apochromat OTA at the sub-$600 price from a major manufacturer can be nothing but a big positive for our hobby.

Click here for more about this subject. -Ed.