今回の特集は、日本滞在の天文ハイアマチュアの「マーティン・ザンダー」氏ご提供の特別Zeiss Micrcoskop Eyepiece S-Pl 10x/20 25mmアイピースについてのリポートです。すべての観望目的に最適なこのアイピースの魅力は、マーテン氏が解説致します。

この機会に、より多くの方々に「Zeiss Micrcoskop Eyepiece S-Pl 10x/20アイピース」の素晴しき性能の全貌を感じて頂ければと考える次第でございます。

リポートをさっそく公開させて頂くため、とりあえずは元の英語フォーマットでご提供致します。マーティン氏へお礼申し上げます。

どうぞご検討下さいませ！

In a practical sense, an accurate judgment of astronomical telescope and eyepiece optical quality is largely a matter of application requirements. For eyepieces in particular, some users require the highest possible contrast while others prefer a super wide field of view. Others worry about astigmatism and yet eyeglass wearers require long eye relief above all. Some observers are more concerned about color fidelity than anything else.


Having an extensive array of eyepiece designs and focal lengths in one's equipment arsenal is obviously the most common way to cover all these various requirements. Having the perfect eyepiece and visual accessory for each end use, and knowing exactly which one that is and why are among the major joys of visual amateur astronomy. However, most of us cannot decide WHICH eyepiece manufacturer is best in any given situation, and as a result observers continue to expand their equipment arsenals, hoping without end to uncover that next panacea. While that may be charming for a good many of us and great news for dealers, the fact is that the more weight and volume and numbers of cases you need to carry the less inclined you will be to transport any of it to your observing site and the less time any of it will actually be used for the purpose intended.


A challenging but effective approach to avoid this pit-fall of apathy is to strictly minimize the equipment you need at your given observing site. Having a well-designed observing kit that represents a significant reduction of your entire arsenal and bringing only that minimum to your site is an approach that has worked very well for me but has taken years to get used to. The key here now is to get an idea of what that equipment might be.


Enter the Zeiss S-PL apochromatic aplanatic orthoscopic microscope eyepiece with 1 1/4" barrels for astronomy. Astronomers might not like to hear that the optical tolerances for laboratory and medical research equipment are far tighter and are manufactured with far stricter technical specifications. The costs and profit margins of such equipment are correspondingly higher so it should therefore be no surprise that Zeiss terminated its astronomy division long ago while the medical research equipment group continues to innovate and thrive.


Thirteen useful categories for eyepiece comparison and evaluation are center sharpness, edge sharpness, field curvature, light transmission, pincushion distortion, color fidelity, glass tone, edge astigmatism, eye relief, field of view, build quality, ease of use and finally, contrast. The Zeiss S-PL was compared to a lineup of other outstanding eyepieces, lenses noted in particular for their excellence in each of the technical categories and are to be considered benchmarks for comparisons in those respective areas.


The Zeiss S-PL 25mm Microscope 48-degree apo ortho eyepiece is a dream come true for planetary observers, eyeglass wearers and anyone else who needs and appreciates the best possible optical quality and ease of use. It can do it all and does it perfectly. It is the famous Zeiss Abbe II kind of perfect. This very expensive lens just disappears. It makes your objective aperture bigger and gives the sensation that the objective is a direct extension of your eyesight. I have personally had such kind of revelation only once before with the introduction of 100-degree eyepieces for general observing. One needs only the Zeiss APO S-PL and a 100-degree, possibly in pairs for a binoviewer, add a top quality ED barlow to boost magnification and the rest is permanently relegated to the closet. Long focal length Cassegraine owners may not even need that barlow!


The panacea of planetary eyepieces exists after all. Just get this Zeiss Ortho and you'll be happy. You'll use your telescope more often and spend much more quality time observing instead of puttering around in confusion. You'll keep your Maks and Dall-Kirkhams perfectly collimated and their top performance will be highly gratifying. You'll have far less to carry around and worry about and ponder over. Finally, you'll never have to make a leap of faith that what you're looking at is the real thing. As long as you own a perfect objective, you'll already know.