The Dobsonian Telescope 节选翻译及个人DIY心得（三）

原文：

2.1Non-Telescopic Telescope Considerations

When you build atelescope, it becomes part of your life—and in the case of a large Dobsonian, a large part of your life.Somehow you must fit it in among your other activities, into your home, andinto your automobile. This is not always easy, and what’s practical shouldstrongly influence what size telescope you build. Your family is aconsideration, too. Can you really afford to build a big telescope, or mightyou and they be happier with a small telescope that would take you away fromhome less and cost less? These are important considerations that you should notignore.

So here are somequestions that you should ask yourself. There is nothing magic about thisprocess and you certainly need not follow it step by step. If you’re already anobserver or telescope builder, you might have a lot of the answers already.Such planning encourages you to think through the reality of owning a bigtelescope.

What are your present observing habits? Even if you’ve been anamateur astronomer for years, you may not want or need a big telescope.Carefully asses what you actually do when you go observing. If your deepestpleasure comes from visiting familiar celestial friends—Andromeda, the Dumbbell, the Orion Nebula—then a big telescope might complicate your hobby without adding toits enjoyment. But if you’re restless and already pushing hard against thelimits of your present telescope as you search out fainter, deeper, less well-knownobjects, then you may need a bigger one.

Where you will observe? If you live in an urban or suburban area,you’ll want to take your telescope to dark skies at least some of the time.Sites that serve well are club observatories, the yard of a rural friend, asmall plot leased from a farmer, parking areas in state parks, and roadsides inisolated areas. Where it is, you must feel safe and comfortable at your site.

How will you transport the telescope? Next figure out how you willtransport your telescope to your observing site. Even if you can squeeze alarge telescope into a small automobile, is there space left over for otherpassengers? For a tent, stove, cook set, and sleeping bag? There’s no lack ofoptions beyond the family car, consider vans, pickups, and mini-trailers.

Where will you store the telescope? Before you even start it, decidewhere you will keep your telescope. Garages, basements, attics, porches, sheds,and backyard observatories are the most common storage areas. Storage may setan upper limit on how big it can be. Work out how you will move the telescopefrom storage to the place you observe. Can you avoid steps? Carrying heavyequipment up and down stairs is enough to kill anyone’s appetite for observing.

What happens “the morning after?” The biggest enemy of amateurastronomy is sleep. Or rather, lack of sleep. When you own a really largeinstrument, you can’t observe for an hour—you’re going to put in all-nighters. Just Knowing that each time youstay up late, you’ll have to wake up and get the kids off to school and then strugglethrough. You will need to arrange your schedule to sleep undisturbed themorning after an observing session or you won’t enjoy your large telescope.

What is the cost? Although the mirror is the largest single expense,you will soon find yourself writing checks for goodies like hardwood plywood,aluminum tubing, varnish, eyepieces, and more than a few tools. Better that youplan ahead than run out of money halfway through the project. Be sure that youtalk it over with your spouse before you’re psychologically committed to a telescopeplus four-wheel-drive truck—remember thatalmost any car can tow a small trailer, and that’s all you’ll ever need.
What is the total cost? Don’t act too surprised when your spouse decides tospend an amount equal to the cost of a telescope on his (or her) own hobbies.Wait until the kids decide to stake their claim to part of the family’s hobbybudget! The decision to build your dream telescope could add up to a figureconsiderably greater than the cost of the telescope alone.

Check out somebig Dobsonians at a star party. Have you actually observed with a largetelescope? If you have not, make sure you do. Every year there are dozens ofstar parties where you can see and look through a variety of telescopesincluding big Dobsonians: Riverside, Stellafane, The winter Star Party,Astrofest, The Texas Star Party, Table Mountain Star Fest, … the list goes onand on. Check out upcoming dates and locations in Sky and Telescope. Even ifyou’re not the type who normally likes these events, go to at least one. Spendthe day looking at telescopes. Inspect them. Move them. Ask questions. Spendall might looking through telescopes. Look, learn, evaluate, and observe.

Going to a starparty is a great reality check. Inform your dreams with hands-on experienceabout how it really is. Chilly, damp, bug-infested nights under a beautifulsky. Cold nights. Clouded-out nights. Nights when it rains and the tent leaks.Mornings when the car won’t start. Does the excitement of observing outweighthe hassles?

If you go tostar parties, you will see great telescopes. You will also see telescopes thatdon’t work quite right. You’ll see telescopes that wiggle and jiggle. You’lltry to look through telescopes that don’t quite balance. You’ll observe withtelescopes whose images aren’t quite sharp. Maybe not disasters—but scopes that fall a bit short.

You’ll alsolearn how big “The Big Ones” really are. It’s easy to draw up some sketches andtell yourself that a 10-foot tube isn’t so long and 175 pounds isn’t so heavy,We want you to imagine lugging each one into your back yard and assess thelimits of your strength and patience. We don’t want to scare you—we just want you to know what you’re getting yourself into.

But don’t letsilly fears take over either. When you pick up a 25-inch Dobsonian on a pair ofwheelbarrow handles, you’re lifting less weight than someone hefting an 8-inchcatadioptric. And if you do it right, it’s actually easier to set up a bigDobsonian than it is to haul out a couple garbage cans to the curb on trashday. Check out the pictures in this book and you’ll see how easy using a bigscope can be.

Lastly, assessthe rewards. Some people marvel when they look through a telescope and somepeople don’t. If you are among those who would rather curl up beside the firewith a good book than shiver at the eyepiece, then stick with your books. Butshould you find yourself craving more galaxies, fainter nebulae, and betterviews of the planets—the biggesttelescope you can afford may be the right telescope for you.

译文

2.1 非伸缩望远镜的考虑

当你制作一个望远镜，它会成为你生活中的一部分，如果是一个大口径DOB的话，就是你生活中很大的一部分。你要想办法让它适应你的方方面面，你的房子还有你的车子。这并不总是简单的，而且很多实际因素会大大的影响你制作望远镜的尺寸，你的家庭也是一个考虑的因素。你是否真的有能力做一个大的望远镜？或者说一个能让你少出门的、更便宜的小望远镜是否能令你和家人更幸福？这些都是你不能忽视的重要的考虑因素。

因此，这里有一些问题，你应该问自己。这个过程没有什么神奇之处, 你当然不必一按着步骤来。如果你是一个老鸟（不是老菜鸟），那这些问题你肯定已经有很多答案了。这样的规划会帮你明确拥有一个大望远镜的可行性。

一、你现在的观察习惯是什么？

即使你是一个有多年经验的老鸟，你可能不想要或需要一个大望远镜。仔细想想你去观星时实际上是看什么目标。如果观察那些为人熟知的深空天体—仙女星系、哑铃星云、猎户大星云能带给你内心深处的愉悦，那一个大望远镜会搞乱你的习惯而且不会带来更大的快感。但如果你急切的想要突破望远镜的限制，去探索一些暗弱的、更深层次的、不为人所熟知的目标，那你就需要一个大望远镜。

二、你要到哪里观星？

如果你住在城市或者郊区，至少有一些时间里你会想把望远镜带到黑暗的天空下。好的观星点，诸如俱乐部的天文台、农村朋友的院子、在农民租来的小基地、国家公园的停车场和隔离区的路边。不管在哪里，务必确保安全和舒适。

三、如何搬运望远镜？

接下来想想怎么将你的望远镜搬到你的观星点。即便你能将一个大望远镜塞进一辆小汽车，还有余下的空间给同行的小伙伴吗？还有帐篷、火炉、锅碗瓢盆、睡袋。除了轿车外，不妨考虑一下面包车、皮卡还有小型拖车。

四、望远镜存放在哪里？

在你开始之前，要决定将望远镜存放在哪里。车库、地下室、阁楼、廊棚，后院天文台是最常见的存放点。存放点会给你的望远镜设置一个体积上限。想一个将望远镜从存放点搬到观星点的好办法。你能避开台阶吗？拖着重型装备上下楼梯足以冷却再强烈的观星意愿。

五、天亮之后

天文爱好者最大的敌人是睡眠，或者说睡眠不足。当你拥有一个大家伙，你不会一晚上只看一个小时，你会通宵。你每次熬夜之后都要爬起来送孩子上学，一路上都得死撑。熬夜观星后，你需要安排一段不被打扰的时间补觉，否则你很难享受你的大望远镜。

六、费用多少？

虽然镜片是最大的单笔开销，但你很快会发现你要为其它东西诸如木板、铝管、油漆、目镜还有一堆工具付账。提前计划比在项目中途用完钱要好得多。在你全心投入到一个大望远镜加一辆四驱货车（要记住，大部分车都能拖个小拖车）前，一定要和你的领导商量。这就是你要做的事情。

七、总开销是多少？

当你的领导决定花费和你的望远镜造价相当的金钱在她的爱好上时，别表现得太惊讶。还有小孩们参与家庭爱好预算的诉求。制作梦想之镜的决定会带来一笔远远大于镜子造价的开销。

       参加一个星空派对体验一些大的DOB望远镜。你用过大望远镜进行实际观测吗？如果没有，一定要试一下。每年都有几十个星空派对，那里你可以看到并仔细观察各种不同的望远镜，其中当然包括大型DOB。一系列的星空派对举行的时间和地点能在《天空与望远镜》上查到。就算你是不喜欢这些活动的人，至少也要参加一个。花上一整天的时间看望远镜，观察、移动它们，问问题。把所有精力花在望远镜上，看、学习、评估、观察。

       参加一个星空派对是一个很好的实际体验。实际经验会让你了解你的梦想实际会是怎样的：美丽的天空下阴冷潮湿满地臭虫的夜晚、寒冷的夜晚、乌云密布的夜晚、雨夜加漏水的帐篷、汽车发动不了的早餐。观星的兴奋能盖得过麻烦吗？

       如果你去参加星空派对，你会看到一些很棒的望远镜。你也会看到一些不太对劲的望远镜。摇摇晃晃的、不平衡的、景象不够锐的。也许这些毛病不是灾难，但却大打折扣。

       你还会见识到多大才叫真正的“大”。这比画一堆草图更直观的告诉你，10英尺的管不算长，175磅的重量不算重。我们要你想象一下把每个大家伙都往你的后院拉，还有评估一下自己力量和忍耐的极限。我们不是在吓唬你，只是想让你知道你将要面对什么。

       别让愚蠢的恐惧接管任何事情。当你推着一个装有轮子和把手的25寸DOB望远镜，你举起的重量比一个8寸反射镜还要轻。如果你操作正确，实际上架设一个大型DOB望远镜比在反垃圾日将两个垃圾桶拉到路边更简单。看看本书的图片，你会发现使用一个大望远镜是多么的简单。

       最后，估算总账。有些人通过望远镜观测会觉得很惊奇，有些人觉得稀松平常。如果你宁愿缩在火堆旁看书而不愿在目镜后发抖，那么，继续看书吧。但如果你发现你自己渴望看到更多的星系、暗星云、更好看的行星，那么你能承受的最大的望远镜就是最好的望远镜。

心得：

       翻了一大段，似乎仍没有什么实质内容，恐怕令看官失望了，请再耐心等等。

顶老弼！

kevinliw 发表于 2017-2-28 22:03
顶老弼！

谢顶！

翻译工作量大，不容易！顶一下弼马温！虽然还没到实质内容，这些也很重要，即使写中文这些也是不可或缺的。

翻的不错，辛苦了！

楼主辛苦了，坐等更新。

原文：
2.2 Tough Telescope Considerations
It is tempting to flip through a book like this one, get all excited, and place an order for a 36-inch mirror. Don’t do it. Although you might succeed and build a fine telescope, the odds are against you. History say so. When the first big, affordable first came out—17.5-inch mirrors—lots of telescope builders rushed to place an order. Time went by, and then one day the UPS truck pulled up and delivered a huge, heavy box. The proud new owners couldn’t believe what they saw. The mirror was far bigger than they had ever dreamed!
Admittedly there was a lot less information available in those days. And because few of those eager-beaver builders had ever seen a 17.5-inch telescope, they didn’t have a clue how BIG it would be. Many of those mirrors languished in the back of a closet for years. A couple decades later, it is safe to say that most of them are now in telescopes, but we don’t want to oversell you on big scopes. Instead, we want you to plan carefully. We want you to enter into this project with open eyes. Make no mistake: building a telescope is a big, time-consuming project. We want you to finish it and to enjoy using it for years in the future.
Let’s talk about motivation: Why do you want a big telescope? If owning the biggest scope in three states is some kind of status thing or ego trip, have we got news for you! The average stargazer is drawn like a magnet to the largest telescope. You think you’ll get your big scope built and be the center of attention at every star party forever. But some day somebody is going to set up a bigger telescope right next to you. Hah! Suddenly your telescope is not so big anymore. Where have all the stargazers gone? Next door to look through the “big” one.
Let’s talk about using telescopes: How often do you go observing with your present one? Do you think you’ll feel justified spending the same amount of time with your new 36-inch Dobsonian under the suburban skies in your back yard? If you can truthfully answer “yes,” then a really big telescope may be for you. Otherwise, go for something smaller that you’ll take out regularly. Even a good pair of binoculars is a lot better than a 36-inch telescope sitting in storage.
Let’s talk about personal energy level. You have to be pretty hyper or pretty determined to take a big telescope out for a night of observing. If you have to load up, drive an hour, set up, observe, load up, drive an hour, and unload each time you want to observe, you’ll start to feel tired and get a headache every time you think about your telescope. But aspirin doesn’t cure telescope exhaustion.
Let’s talk about health. This is a difficult topic, but if your joints ache on damp nights outdoors, and you are tempted to spend more time in the cold, the consequences are predictable. Allergies, arthritis, angina, and age all have the potential to reduce your observing pleasure. Take the state of your health into account as you plan for your telescope.
Let’s talk about size and strength. If you are 5-foot-2 and weigh 100pounds soaking wet in your clothes, it’s fair to say your 25-inch dream telescope is bound to be a lot larger and heavier than you are. The height of the eyepiece at the zenith is equal to the focal length of the primary mirror, so if you had a 12-inch f/5 Dobsonian, you could probably observe with your feet flat on the ground. Don’t take this to mean you can’t have a 25-inch telescope, but please understand, we want you to know that you’re letting yourself in for a lot of late-night ladder climbing.

译文
2.2        艰难的抉择
        翻阅像本书这样的教程，会使你蠢蠢欲动，然后马上下单买一块36寸主镜。别这样做！虽然你有可能成功，造出一台好望远镜，但概率上是不利于你的。不妨以史为鉴。当第一款消费级大炮—17.5寸主镜问世时，一大批造镜者蜂拥订购。随着时间流逝，终于有一天，快递小哥送来一个又重又大的箱子，踌躇满志的新主人简直不相信自己的眼睛。镜子实在是比他们想象中的要大得多。
        不可否认当时信息比较匮乏，几乎没人见过17.5寸望远镜，人们对这个级别的镜子根本没啥概念。很多这些镜子只能压在箱底，一年又一年。直到几十年后，我们才敢说大部分的镜子都做成了望远镜。我们不会向你吹嘘那些大镜子，相反地，我们要你仔细地规划。我们希望你睁着双眼，明明白白进坑。毫无疑问，做望远镜是一件费时费力的事情，我们希望你在未来的几年里能完成并享受使用它的乐趣。
        我们谈谈动机。你为什么想要一个大望远镜？如果说拥有一个三个州里最大的望远镜是某种身份或者面子的事情，或者说是追求自我的满足，那没什么可说的。一般的观星者会被最大的望远镜像磁铁那样吸引住。你认为你能做好你的望远镜并成为在星空派对上永远被关注的中心。但总有一天，会有人在你旁边架设一个更大的。啊！突然间你的大望远镜不再显得那么大了，那些观星者都跑哪里去了？去隔壁看那个“大”的
        我们来谈谈望远镜的使用。你多久用你现有的望远镜看一次星星？你觉得你会花同样多的时间用你新的36寸DOB吗？如果你可以如实的回答“是的”，那一个真正的大望远镜就是适合你的。否则，就找一款小一点的你能经常使用的。即便一个不错的双筒也比一台在储藏室角落吸尘的36寸大望远镜好得多。
        我们谈谈个人的精力。外出看一晚星星，你必须很兴奋或者下很大的决心。如果每次你想出去看星星都必须打包装车、开一个小时车、架设、再打包装车、再开一个小时车、卸车，每当想到你的望远镜，你都会感到疲倦和头疼，阿司匹林都无济于事。
        我们谈谈健康。这是一个艰难的话题，如果你的关节在户外潮湿的夜晚会疼痛，又妄想在天气冷时花上更多的时间，那么结果是可想而知的。过敏症、关节炎、咽喉炎和年龄都有可能减少你观星的乐趣。规划你的望远镜是请把你的健康状况考虑进去。
        我们谈谈尺寸和强度。如果1米6的高度和90公斤能把你搞得全身湿透，公平地说，你的25英寸梦想望远镜一定会比你壮得多，也重得多。天顶姿态的目镜高度跟主镜焦距基本相当，所以如果你有一个305/1525的DOB望远镜，你刚好不用踮脚。当然这并不意味着你不能拥有一个25寸望远镜，但请理解，我们希望你知道，你这是在让自己在半夜爬梯子。

原文写的好，翻译的也好，spouse译成领导，太有才了！

skywalkerxx 发表于 2017-3-18 19:35
原文写的好，翻译的也好，spouse译成领导，太有才了！

谢谢谬赞，如果发现错误不妨直接指出。