为毛高桥的三脚架都是木头的？
还卖的挺贵。我研究了下手上的架子，这木头好像也不是特别的硬，一般的红木而已吧。
难不成喜欢其吸收震动的效果？
高桥也有金属的，更贵 木头架子虽然看着有点楞，但同样重量下的稳定性可能是最好的（木材硬度上远低于金属，利于吸收微小震动的能量，类似于橡胶垫的作用）
事实上，工程测量用的仪器基本上都是配的木质三脚架，从没听说过测量员抱怨晃的 本帖最后由 cosmosEX 于 2014-3-13 19:03 编辑
The terms “stable” and “accurate” must be taken in their strictest sense here!This is because each little jerking motion and each lack of precision, while hardly noticeable to the eye of the observer, is mercilessly amplified by the magnification used with the telescope. A small jerk measured in millimeters can quickly cause the observed celestial object to disappear from the telescope’s tiny field of view. This demand for stability applies not only to the actual mount but equally to the associated tripod or stand which in most cases is the principal weak point of the system.
The requirement of having the greatest functional accuracy possible along with a low vibration setup of course entails a certain level of mechanical stability. The designer can address a critical aspect such as vibration dampening only by using materials of solid construction, and especially a reasonable weight ratio between mounting and telescope tube.
On the other hand, this requirement conflicts with the desire of the user to have a compact, light, and easily transportable unit. The mount must therefore not be too heavy since otherwise the equipment becomes unwieldy. And this is not the only area where the gap between need and necessity becomes very wide. Since the component “mount” is not very high on the list of performance criteria for the scope, the willingness to invest a significant portion of the purchase price in an effective mount is quite low, especially with first-time telescope buyers. Of course, suppliers then react accordingly by offering telescopes with highly impressive apertures and magnifications, but placed on light and cheaply produced mounts. Although these mounts may no doubt be able to hold your scope, it is often out of the question to speak in terms of stable and accurate handling. What must always be taken into account is that the best optics can never be utilized properly if the mount is not worth anything. For example, the constant backlash motion or lack of tracking can cause every observing session at higher powers to become a war of nerves, or even frustrate it entirely.
The best mount is also not of much use if it does not have the right foundation. This is generally supplied in the form of an extendable tripod made of hollow aluminum. Less commonly used as tripod material is wood, which is more effective in attenuating vibration.The steel post that used to be quite common as the support structure is rarely sold now. In the vast majority of cases, the proud owner of a purchased telescope will thus have to make do with an aluminum or steel-tube tripod. Yet it is precisely these that are frequently the weak point in the stability of the overall telescope design. One reason no doubt for this is in part the excessive trend to minimize weight that is spreading to an ever-increasing degree from the telescope itself to the mount and on to the tripod.
In fact, the opposite conclusion would make more sense for reasons of stability, since it is after all only a stable and massive support that can effectively dampen a telescope that has started to vibrate. As a result, it is not surprising when a relatively heavy telescope causes the relatively small mount underneath it to vibrate along with it, instead of being attenuated by it. And this whole system is still supposed to be supported by an overloaded tripod made of thin, light hollow sections. Another reason for this no doubt is the potential for the manufacturer to reduce costs, which can best be saved on the tripod after taking into account the expensive optics and mechanically costly mount.
————《Handbook of Practical Astronomy》
很多飞机也是用木头做的 本帖最后由 sktang 于 2014-3-13 22:20 编辑
看著舒服,穩重有份量
木头架子比一般的铝管架子好多了，只是重一些 Crazyhorse 发表于 2014-3-13 18:40
木头架子虽然看着有点楞，但同样重量下的稳定性可能是最好的（木材硬度上远低于金属，利于吸收微小震动的能 ...
一般测量的经纬仪，最多2、3公斤，用木头感觉纯粹是为了省钱。
tbb1 发表于 2014-3-14 09:38
一般测量的经纬仪，最多2、3公斤，用木头感觉纯粹是为了省钱。
看最后一句，“Another reason for this no doubt is the potential for the manufacturer to reduce costs, which can best be saved on the tripod after taking into account the expensive optics and mechanically costly mount.”
cosmosEX 发表于 2014-3-14 10:38
看最后一句，“Another reason for this no doubt is the potential for the manufacturer to reduce cos ...
这个是针对铝架子说的吧
tbb1 发表于 2014-3-14 11:17
这个是针对铝架子说的吧
是的呢。{:3_207:}
其实木架子自制也不错
tbb1 发表于 2014-3-14 11:17
这个是针对铝架子说的吧
真没见过便宜的木架
cosmosEX 发表于 2014-3-14 11:20
真没见过便宜的木架
看来我还得把手上那个高桥木架子当宝供着，差点嫌他丑劈了当柴烧
tbb1 发表于 2014-3-14 11:34
看来我还得把手上那个高桥木架子当宝供着，差点嫌他丑劈了当柴烧
老兄是哪款高桥脚架？上个图，我有意~
gki2008 发表于 2014-3-13 20:43
很多飞机也是用木头做的
木头不能直接做飞机 都要经过化工处理用合成树脂替代木头中的一些易变质的成分。苏联在二战中大量使用了这种木料，和金属相比强度足够但重量很大只能从别处减重，导致苏联战斗机的性能空间只能局限在低空。而且木头韧性很差，德国战斗机机炮发射的β型薄壳高爆弹可以对苏联战机的木质蒙皮造成巨大创伤。所以说木质只是权宜之计，后期有色金属产量提高之后苏联的拉7拉9战机也开始使用全金属制造。
木头架子震动小。 阵风V-1 发表于 2014-3-18 12:39
木头不能直接做飞机 都要经过化工处理用合成树脂替代木头中的一些易变质的成分。苏联在二战中大量使用了 ...
做飞机的木头,当然要经过必要的处理
不要说是做飞机了,就是做家俱也要经过必要的处理
阵风V-1 发表于 2014-3-18 12:39
木头不能直接做飞机 都要经过化工处理用合成树脂替代木头中的一些易变质的成分。苏联在二战中大量使用了 ...
二战中的英美兵用木制的滑翔机降落在德国。但滑翔机需要轰炸机用绳子拖。能载兵和小汽车。
2片试螺旋桨也有用手雕刻出来的，非常细的工应为不平衡就会震到断。
现代的滑翔机也有木的。
apple1234 发表于 2014-3-19 01:31
二战中的英美兵用木制的滑翔机降落在德国。但滑翔机需要轰炸机用绳子拖。能载兵和小汽车。
2片试螺旋桨也 ...
如果我没记错的话 二战的军用滑翔机应该是金属框架帆布蒙皮
tbb1 发表于 2014-3-14 11:34
看来我还得把手上那个高桥木架子当宝供着，差点嫌他丑劈了当柴烧
好霸气的言论，想起了 石崇和外戚王恺斗富的场景。
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