折射望远镜:The AT111（翻译）
啊，这款折射望远镜可称得上是一款设计完美的望远镜了。至少它体积更小。如果你想要以远大于4到5英寸口径的望远镜作为入门的话，就会不断需要更大（当然也更贵）的装配。
也许你最近还没有注意到，现在这类产品无论是在中端还是低端都已经开始多了起来。如果你是个对镜头要求很严格的人，那么现在就已经有了会让你更加钟爱的产品了,并且价格也不贵。在那些已经开始泛滥的众多商品中，偶尔也会发现很不错的产品——这款AT111就符合这些条件。
这款TMB的三角支架折射望远镜构造精良：111毫米的口径， F7的焦比。有2.7英寸的长行程可旋转调焦座，还有刀口挡板和校准镜头座，而更吸引人眼球的是它的透镜是奥哈拉（O’hara）牌的。
它还配有可伸缩的遮光罩和黑色按压配合的镜头盖——从审美角度讲我真觉得这架望远镜漂亮极了。不过我更希望镜头盖是银灰色或者绿色的，这样就可以和它的装配相搭配，当然这有点吹毛求疵了。另外，望远镜镜筒重14.7磅。
该设备的组装情况和表面的抛光都非常好。镜筒表面使用的是优质的汽车喷漆，虽然没有粉末涂料耐用但是做工还是非常好的，而且如果按照标准保养的话也会很耐用。调焦座经过电脑数控机床处理并做了银灰色的阳极化抛光处理，非常精致，后面还会有更多对它的介绍。
这款望远镜的设计是一流的。白色镜筒与银灰色调焦座在颜色上很谐调，并且二者的颜色又同镜身上的绿色装置搭配得天衣无缝。调焦座的调焦行程很大——这很大程度上是为天体摄影而设计的。对焦的时候，我的登克宾诺（Denk Binos）的对焦仪有点问题，但是短光路的双目装置应该不存在这个问题，而且我也听说这种装置如果不用OCA的聚焦设备也可以使用。调焦座的齿条和齿轮都是重负荷型，我第一次看见这种调焦座还是在TMB 130ss上（后来TMB的调焦座都换成了羽触牌[Feathertouch]的），而且说实话，很高兴发现这样的调焦座再次上市。现在市面上的进口调焦座种类繁多，这与一开始只有昆明牌或GSO的特有的调焦座相比，无疑好了很多。
那么现在我们就要关注一下这种调焦座的产地了——我不知道它是哪里生产的，但是我可以把它完整地介绍给你。在当今这样一个克隆时代，它是独一无二的。
我喜欢好的调焦座——谁不是呢？它用上去有种机械的阻尼感，转动它调焦的时候会有一种厚重之感。它的表面柔滑但力量感又很强。而这一款调焦座就很好地传达了这种感觉。
这款调焦座是定制的2.7英寸的重载调焦座，它表面非常光滑并且突出了那个11-1减焦系统——只用于目视的话是绝对奢侈的，但对于摄影来说却是很重要的。它有一对齿条和齿轮，而且质量上乘。只需要轻轻扭一下调焦座的末端它就会转动，并且聚焦把手还留在原位。在写这篇文章之前这个望远镜我已经用了几个月了，从夏到秋（又从秋到冬），这之前它都十分结实。我觉得是因为天气变冷才使得调节螺丝变皱，还有些移位。但只需要调节一下而已，还不用拿去修理。更新：其中有一次，我不知道发生了什么，那之后我用它的时候问题就不见了，很是奇怪。虽然还有非常非常小的一点移位，但是对于我来说还不需要为这个而费心。
这款望远镜的箱子只能装下镜筒本身，虽然也可以把镜筒箍放在镜筒上一同装进箱子，但还是比想象的要小。但是不管怎样，你也是不可能把天顶镜和鸠尾板都留在镜身上放进箱子里的。
而这是次要的，只不过是我自己的小烦恼罢了。因为我喜欢既可以保存又可以携带望远镜的箱子，并且也更加钟爱那种可以放得下带着天顶镜、镜筒箍、鸠尾板和寻星镜的望远镜箱子。如果箱子里还可以多放下几个寻星镜就更好了。当然，你也可以用另外一个箱子来装那些必备品。与望远镜配套的这个箱子大小设计得正合适，足够起到保护镜筒的作用，但鉴于望远镜是精密仪器，你可以考虑再购置一个箱子（比如说阿拉镜体卫士这个牌子就不错）。（值得注意的是发货时与AT望远镜配套的箱子不在两年保修期内。一个免费的箱子怎么也比没有箱子要好，很显然，AT这么做就是迎合了大众的这种心理。但是也别指望可以一直只用这一个箱子——我也是这么想的。）
观星测试表明，它的光学效果也是一流的。只是会有轻微的色差和伪彩现象，但影响不大。在我看来，人们总是过于在意伪彩现象（很可能是因为它最容易辨别）。的确，一个真色彩的光学系统是有很多优点，但事实是，只有极少数的折射望远镜能够做到真色彩，而那样的望远镜一般都很昂贵。这款AT111在观测月球的时候散射现象不是很明显——要么是紫色要么是黄绿色，这要看你偏好于用焦点的内侧还是外侧了。我在观测的时候没发现有散光现象，压力和降温对观测也没有什么影响（现在只有个别中等水平的折射望远镜才会存在这类问题）。我也没有发现视野的曲率。至于拍摄性能——我正要把这架望远镜借给我的朋友，他是个天文摄影师，等我拿到他拍的一些照片我会继续更新这篇文章。
用这个光学镜观测月球和木星很有意思，因为它的放大倍率很高，比用CA观测时的效果好得多。在观测木星的时候，我发现它的折射差数造成的效果要比CA的大，而且大很多。在观测条件良好的时候，即使木星是在天空北部比较低的位置，我们也轻易地找到了它的几条环带，有几次还观测到了光环的细节。木星的伽利略卫星是很明显的一个圆盘（当然，我没有看到真正的圆盘，那只是衍射效应罢了，这样一个小型望远镜还看不到它。），而我还试图捕捉到一两个卫影凌行星的景象。能看一眼卫星在行星上投下的一个黑影总是很让人兴奋的。
调焦的时候会有很明显的咔嗒声，而且光学部件放大的效果很好——尤其是观测月亮的时候，它能轻易地实现放大三百倍而没有图像干扰。而在观测木星的时候我特意将放大倍数限定在220倍到240倍的范围内，正好是每英寸放大五十倍。
总之一句话，我真希望这架望远镜是属于我的私人物品。
110毫米口径的物镜要比102毫米的物镜的辨析率和聚光度要好一点，但是相差不大。因为聚光度每增加18%，相应的星等只会增加十分之一。102毫米口径的杜氏极限是1.14而110毫米口径的是1.05。差别不是很大，但是如果其它指标都相同的话这就值得注意了。
虽然这款望远镜装本的是自动跟踪导星GM8地平仪，但如果你想从事天体摄影，那就还得提高一下配置。我个人认为，航海者这个牌子的望远镜就很物美价廉，而AT111则有点贵——但我已经说过了我还是喜欢真正实用的装配（安装时间越短越好）。我知道航海者最近推出了一款重型装配，不知道那是不是一个明智的选择。我用G11（在我的观测台）或者用环宇之星（Unistar）的中型三角架安装好AT111。同时用这二者的安装时间是最短的，只用G11比较繁，而单用环宇之星（Unistar）会多用一两秒的时间。而我推荐环宇之星（Unistar）因为它方便随身携带，而GEM则适合中等放大倍率的观测要求。
还有几个你需要考虑自己购置的东西—— 一个寻星镜，一个你喜欢的鸠尾板和一套镜筒箍。AT为这款望远镜提供了一套124毫米的镜筒箍，但不是免费的。如果需要你可以花120美金买到。
至于寻星镜，我倒是十分喜欢那种近几年很流行的多十字叉丝寻星镜，既不是很贵质量又好，和其它种类的一样，也是有金属的和塑胶的。
如果这是你的第一架复消色差折射望远镜，那么你还需要一个天顶镜。我推荐用３－６毫米耐格勒变焦的天顶镜。其实不管怎样我都会推荐它的。这款望远镜的目镜也是很理想的装配，因为它是可以在3毫米的镜片上捕获放大259倍后的效果的高能装置。还有要注意的是，由于所成的像与目镜之间的距离是很小的，而如果要戴着眼镜观测的话（虽然用短焦距的望远镜很少会遇到这样的情况，但还是会有），由于出瞳距离很小，那就需要调整好出瞳距离来找到物像了。
总体来说，这次试测感觉非常好，这架望远镜完全可以和同一价格范围内相近大小的望远镜相媲美，甚至要超过它们。但是这种三合透镜还是存在一些缺点的——也就是冷却问题并且会影响观测者的校准。但这些对于它来说是次要的了。如果说它不完美，那我就没见过比它更完美的了。
总而言之，如果你正想在这个价位上选择一款望远镜，那么这款AT111绝对是最佳选择，值得考虑。
欢迎朋友们指出存在的问题哈～::070821_01.jpg::
附原文：
Ah, the refractor. It's quite possibly the perfect design for a telescope.In smaller sizes anyway.If you start heading much beyond the 4-5 inch range, the increasing demand for a larger and (more expensive) mount．
In case you haven't noticed it lately, there's been something of a boom in the middle to low end of the scale on these puppies. If you're a lenshead, there's more here to love - and at lower prices - than ever before. Through the deluge of common offerings, every once in a while you find one that stands out - and the AT111 does just that.
This TMB designed 111mm diameter f7 focal ratio triplet refractor is well constructed, offers a (proprietary?) 2.7" rotating focuser with a ton of focus travel, knife edged baffles, collimatable lens cell, and touts it's use of O'hara glass.
The dew shield is retractable, and the cap is a press fit.The cap is black - aesthetically as I think this scope is a real looker, I'd prefer it to be either grey or green to match the trim, but that's a niggle. The weight of the OTA alone is listed at 14.7lbs.
The fit and finish is quite good.The tube is painted with an apparently automotive quality paint, and while it's not quite as durable as a powdercoat, it's well done, and should stand the test of time with the standard precautions.The focuser looks to have been CNC'd with a grey anodized finish and is a very nice part - but more on that later.
The styling is first rate.The white otais offset by the grey focuser and trim, and both are complimented by the green trim right found on the tube.The focuser has a TON of focus travel - most likely for astrophotography.I had some issues reaching focus with my Denk Binos, but binoviewers with a shorter light path shouldn't have a problem, and I've heard reports that they indeed work without an OCA.The focuser is the heavy duty rack and pinion that I first saw on the TMB 130ss (on that scope it's since been replaced by a Feathertouch), and honestly, I'm glad to see it back on the market.It's a definite step up from the typical focusers from Kunming or GSO that so many of the imports sport these days.
And that leaves us as to where the telescope is manufactured - I can't tell you were it comes out of, but I can tell you that as a package, it's fairly unique in - which in and of itself is a surprise in this modern clone world.
I love a good focuser - I think we all do.There just something mechanically sensual about it.Rack it in, rack it out.There's something calming in the motion.The smoothness, and yet there's a sense of strength.And this focuser conveys that quite well.
It's a2.7 inch custom heavy duty focuser, whichI found to be quite smooth and features an 11-1 reduction gearing - a definite luxury for visual use, but a bit more critical for photography. It's a rack and pinion, and a good one at that. In a slight twist (no pun intended) the end of the focuser rotates, but leaves the focus knobs in the same place.I've been using the scope for several months as of this writing, and until recently the focuser had been quite solid.As summer has turned into fall (and as fall is turning to winter) I think the cold weather has caused one off the adjustment screws to contract a bit the end result is there's a little shift in the focuser that wasn't there earlier this year.More than likely it's a simple adjustment, but it's not bothered me enough to deal with it yet.UPDATE: In one of those - I'm not exactly sure what happened moments - the next time I used the scope, the problem had nearly vanished.Go figure.A very very very minor amount of image shift remains, but for my useage, it's not nearly enough to bother with.
The case for this scope is smaller than you would expect - it's pretty much large enough to store only the OTA, although you can store the rings on the tube as well.You won't, however, be leaving the diagonal on for storage tho, nor can you leave the dovetail plate attached.
This is a minor point, but something of a pet peeve of mine.I tend to use cases both for storage and transport, and am very fond of a case that allows you to store the scope with diagonal, rings, dovetail and finder.It would also be a bonus to have space inside the case to store a few eyepieces.As it is, you are committed to taking another case along for the necessities.The case is of fairly decent construction and will do it's job protecting the scope, but you this telescope is a nice piece of gear and you may with to consider getting an additional case (ala ScopeGuard) down the road.(It's interesting to note that the case shipped with the telescope is not covered under the AT two year warranty.Evidently AT's take on it is that a free case is better than nothing, but don't expect to drive over it and have the case stay in one piece - and I'd have to agree.)
The optics are first rate, as evinced by the star test.There's a small amount of spherochromatism and false color, but it's not terribly objectionable.Peopletend to make much of false color - too much in my opinion.(Probably because it's the easiest thing to pick up on in a system.) Yes, there are definite advantages to a color free system, but the fact of the matter is very very few refractors are going to be truly color free - and those are going to be very expensive.With the AT111, there was only a small amount of fringing on Luna - either purple or yellow green depending on which side of focus you're favoring.I noted no astigmatism, and no issues with pinch or cooldown (things that seem endemic with medium level refractors these days).Visually I noted no field curvature.As per photographic performance - I'm loaning the scope out to an astrophotographer buddy of mine and I'll update the article when I get some photos.
Viewing Luna and Jupiter was a hoot with this optic, it took magnification well, and what little CA there was I didn't find intrusive.I found the effects of differential refraction to be more profound on Jupiter than the CA.Significantly more profound in fact.In good seeing conditions, even with Jupiter so low in my northern sky, we easily caught several belts, and occasionally glimpses of detail within those belts.The Galilean moons were obvious little disks (of course, I wasn't really seeing the disk of the moon, but rather rather the diffraction effects - the resolution on a small scope isn't quite up to that), and even managed to catch a shadow transit or two.The sight of aninky black dot making it's way across the face of a planet is always inspiring.
There was a definite snap to focus, and the optic took magnification quite well - especially on Luna, where it easily handled 300x with little signs of image breakdown.On Jupiter, I was typically limited to magnifications more in the 220-240x range - right around 50x per inch.
Bottom line is, I'd be pretty pleased with it if it were my personal scope.
The 110mm objective does buy you a bit in resolution and light gathering compared to a 102mm objective, but it's not a ton.There's about an 18% increase in light gathering, which translates into about a tenth of a magnitude difference.The Dawes limit with a 102mm scope is 1.14 vs 1.05 in the 110.It's not a huge difference, but if everything else is equal, it is noticeable.
The telescope pairs well with an ASGT/GP/GM8 level mount, although if you want to get into astrophotography, you'll want to step that up just a bit.While I think the Voyager is a great bang for the buck, Personally, I thought the AT111 was a bit too much for for it - but I've gotten to the point I like a really solid mount (the quicker the settle time the better).I understand the Voyager HD (heavy duty) is coming down the pike, and suspect that would be a good match.I mounted the 111 on a G11 (in my observatory) or a Unistar w/ medium duty tripod.With both of those options, settle times were minimal, inconsequential on the G11, and 1-2 seconds max on the Unistar. I'd recommend the Unistar for grab and go, and the GEM for work requiring moderate magnification.
Another couple of options you'll want to consider - a finder of some sort, a dovetail plate in your chosen flavor, and a set of mounting rings.While AT offers a set of 124mm rings for this telescope, they aren't included.They'll set you back an additional $120 if you need them.
As per finders, I'm pretty fond of the ubiquitous MRF (Multi Reticle Finder) that's popped up over the last few years.The price isn't too terrible and it's got a very nice build quality - metal vs the plastic you find in many others.
You'll also need a diagonal and if this is your first apochromatic refractor, I'll recommend a 3-6 nagler zoom.Heck, even if it's not, I'll recommend it anyway.That eyepiece is just about perfect for this telescope, as it forms an entire high power set, yeilding 259x at the 3mm setting.Be aware that if you need to wear glasses to observe (a rarity at short focal lenghts, but none the less) the eye relief is fairly short, and you may want to seek out something with a little more eye relief.
Overall, I found the performance quite good, rivaling other similar sized doublets in it's price range and perhaps even a bit beyond.There are some disadvantages associated with a triplet - namely cool down and end user collimation, but these seem to be the minor trade offs for this telescope.It's not perfect, but I've seen very very few that were.
The bottom line is if you're looking for a scope in this price range, the 111 has a lot going for it, and is definitely worth consideration.
[ 本帖最后由 辛蒂瑞拉 于 2008-12-15 19:34 编辑 ] 原创翻译，鼓励！大家一起来讨论下这篇翻译，看看有没有需要改进的地方。::070821_01.jpg:: 狂顶，学习这样的帖子真是长见识啊
谢谢楼主啦::070821_01.jpg:: 牧夫原创翻译精品啊，厉害::070821_09.jpg:: 这镜子的调焦座巨粗，2.7英寸啊。::070821_11.jpg:: ::070821_09.jpg::
回复 3# laoda319 的帖子
::070821_04.jpg:: The dew shield is retractable, and the cap is a press fit.它还配有可伸缩的遮光罩和黑色按压配合的镜头盖。
What does it mean by "The dew shield "?遮光罩？
Product Details
http://ecx.images-amazon.com/images/I/11CNFZ4F1RL._SL210_.jpg
Telrad Dew Shield+ for Telrad Finders.
From Telrad
List Price: $25.95Price: $24.95
Availability: Usually ships in 1-2 business days
Ships from and sold by Adorama Camera
Average customer review: http://images.amazon.com/images/G/01/associates/network/star40_tpng.png
Product Description The Telrad Dew Shield helps keep condensation from forming on the glass plate of your Telrad. It can be flipped completely over the glass while you're getting that cup of coffee and then rotated upward to allow you to see through to the sky. The Dew Shield Plus offers the same protection but with a bonus. Inside the Dew Shield Plus is a mirror. When the shield is rotated completely backwards, the mirror acts as a right angle viewing device, letting you see the reticle in the sky without bending over the telescope or twisting your neck.
[ 本帖最后由 q5968661 于 2008-12-8 20:48 编辑 ] 天文家园有人在卖这款镜子呢。 Dew Shield 在天文器材上主要是防露筒的意思。 好镜子！超赞！调焦好像是斜齿调焦。::070821_06.jpg:: 这个调焦座我喜欢，2.7英寸的大家伙，而且还是1：10双速的有齿调焦器，以前看到的都是摩擦或者无齿的，有齿1：10还是头一次见到。::070821_04.jpg:: 好精致好镜子 呵呵，挺LZ，原创！！！
原文链接http://www.cloudynights.com/item.php?item_id=1890
AT官网上只看到有66、80ED，这个是老款么？
二手国内同好出价1.2W+，准5寸3片式APO貌似很划算的！ 呵呵，挺LZ，原创！！！
原文链接http://www.cloudynights.com/item.php?item_id=1890
AT官网上只看到有66、80ED，这个是老款么？
二手国内同好出价1.2W+，准5寸3片式APO貌似很划算的！ ...
zhangqicd 发表于 2008-12-17 23:08 http://www.astronomy.com.cn/bbs/images/common/back.gif
哇~出处都找到了!
好细心::42::
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