瞄准镜

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从4x放大看到的景象

望远镜式瞄具英语:Telescopic sight),俗称瞄准镜英语:scope),別稱准镜綾鏡,在中国大陆也称白光瞄准镜,是一种利用折射望远镜原理的光学瞄具。瞄准镜可用于各种需要精确观瞄的系统,但与其它形式的瞄具如机械瞄具红点镜激光瞄准器等一样,最常见的还是在单兵武器尤其是步枪上使用。瞄准镜的光学系统通常在合适位置配备有标线,能够给使用者提供精确的瞄准参照,其光学部分可结合其他光电原件成为在低光和夜视情况下使用。近年皮卡汀尼导轨的出現让瞄具的安裝和使用更方便,目前各国军队的制式步枪几乎都能搭载光学瞄准镜。

历史[编辑]

二战时期瑞典m/1941狙击步枪上装配的德制ZF Ajack 4×90瞄准镜

用光学仪器协助射手瞄准枪械的试验其实最早在17世纪早期就开始了,并且之后两个世纪内出现过许多设计,但因为当时的技术水平这些瞄具的性能十分有限,基本上从来就没有用于过实践。随着文艺复兴时期玻璃镜片制造技术的不断进步,利用光学折射原理进行放大观测的复杂光学仪器开始出现,比如16世纪末发明的光学显微镜。1608年,最早的折射望远镜由三个荷兰眼镜技师发明,并在之后三年内先后被伽利略开普勒两人进行了设计上的改进。而18世纪上页消色差透镜的发明,使得便携尺寸的望远镜开始出现。因为望远镜能让人观测到肉眼很难看清的远处目标,因此被广泛用于天文、航海和战场侦查观测上。随着线膛枪的发明,火器的精度和有效射程不断上升,因而用望远镜辅助枪械进行远程观瞄的需求也越来越高。

真正意义上的枪械瞄准镜是于1835至1840年间发明的。根据1844年出版的《The Improved American Rifle》一书记载,旅美英国工程师约翰·R·查普曼(John Radcliffe Chapman,1815~1899)和当时著名的美国枪匠摩根·詹姆斯(Morgan James,1815~1878)两人合作设计发明了被称为“查普曼-詹姆斯瞄具”(Chapman-James sight)的望远镜式瞄具。1855年,纽约工程师威廉·马尔科姆(William Malcolm,1823~1890)将瞄准镜的设计改进并商业化,使用了望远镜所用消色差透镜,增加了风偏修正和仰角修正。这些瞄具的放大倍数在3至20之间(也许更高)。马尔科姆公司设计的6倍放大瞄准镜(当时称为Hi-Lux型)和其它相似规格的瞄准镜——比如同时期佛蒙特州珠宝商L. M. Amidon生产的瞄准镜,以及同时期的大卫森(Davidson)和帕克黑尔(Parker Hale)瞄准镜——早在南北战争中就成为精确射手步枪上的常见配具。[1][2][3][4]

1880年,奥地利施特龙斯多夫的皇家林业委员August Fiedler发明了早期的小型化望远瞄准镜。[5]之后长适眼距的瞄准镜开始出现,比如二战时期德国Kar98k步枪上的Zf-41瞄准镜。最早用于实战的便携式低光/夜视瞄准镜是二战时期德意志国防军配备StG44突击步枪使用的Zielgerät 1229“吸血鬼”瞄准镜,从1944年一直服役至二战结束。

种类[编辑]

望远镜式瞄具的规格通常用光学放大倍数物镜直径两组参数来形容,比如“10×50”就代表了10倍放大、50毫米(2.0英寸)的物镜直径。一般来说,大的物镜由于能收集更多的光线,能提供长的适眼距,因此目镜的图像更为清晰。固定放大倍数的瞄准镜需要根据具体需求决定放大倍数和物镜直径。

有些瞄准镜则具有可变倍率的功能,可以应对不同距离、目标和光线条件下的观瞄需求。比如低倍数放大具有更广的视野。可变倍率瞄准镜的型号表示为:最低倍数-最高倍数×物镜直径,比如“3-9×40”代表着可在3~9倍之间变换的40毫米物镜直径的瞄准镜。

让人容易糊涂的是,历史上德国(以及其他欧洲国家)的老式瞄准镜曾使用另一套描述系统来形容规格。第二段数字不表示物镜直径,而表示“采光度”。比如一款“4×81”的瞄准镜的图像要比“2.5×70”明亮。但是物镜直径对图像亮度没有绝对的直接联系,因为亮度也可以受放大倍数影响。早期的瞄准镜物镜也通常比现代瞄准镜要小,“4×81”的物镜直径大约是36毫米,“2.5×70”则是大约21毫米。(采光度等于出瞳直径的平方,出瞳直径等于物镜直径除以放大倍数。比如(36/4)^2=81.)

光学参数[编辑]

因为瞄准镜通常是根据用途来制定设计指标的,因此经常会迎合一些专业的光学参数, 比如:

  • 放大倍数(magnification):物镜目镜焦距比。10倍的放大倍数所产生的图像相当于缩短目标距离10倍后观察到的图像。放大倍数应根据使用目的决定:小倍数具有宽视野,且受震动影响小,但不利于观察目标细节;高倍数放大的图像分辨率很高,但视野较窄且对稳定性的要求高。
  • 物镜直径(objective lens diameter):物镜的直径决定的了瞄准镜采光率,也就是目镜图像的明亮度。物镜直径通常以毫米为单位来测量。
  • 视野(field of view): 瞄准镜的视野由其光学设计决定。常用的表达形式为长度比(每100/110能看到多少米/英尺宽度的范围)或者视角值。
  • 出瞳直径(exit pupil):光线经过目镜汇聚后,在目镜后形成的亮斑的直径。瞄准镜内部的镜片和光阑会将收集到的光过滤集中到一道光束上,这就是出瞳光。出瞳光束的直径相当于物镜直径除以放大倍数。因为任何从目镜汇聚放射出的光线必须经过人眼瞳孔后进入视网膜成像,因此为了能最有效的让人看到最明亮清晰的图像,出瞳直径应该等于人类瞳孔的直径(白天大约为3毫米,夜晚最大可达7毫米左右)。越大的出瞳直径,给人感觉成像的亮度也越大。大于瞳孔直径的出瞳直径会导致光束周边多余的光线都被虹膜阻拦而被“浪费”掉;而如果出瞳直径小于瞳孔直径或仅部分出射光被瞳孔接收,则会产生晕影现象使得有效视野缩水,大大增加观瞄的难度。另外,较小的出瞳直径意味着眼睛必须在目镜后方确切的位置,这不仅使得瞄准速度下降,更会使射手感到疲惫。因此,绝大多数使用者在选择瞄准镜时都会考虑选用稍微大于瞳孔直径的出瞳直径。
  • 适眼距(eye relief):能在避免晕影清楚看见影像的情况下眼睛与目镜间所允许的最大距离,目镜焦距越长,适眼距越长。常见的望远镜的适眼距可以在25毫米(0.98英寸)到100毫米(3.9英寸)以上。枪械上所用的瞄准镜通常为了避免观瞄时稳定困难或者目镜因为后坐力而磕碰使用者的脸和眼睛,都会采用较长的适眼距。手枪或一些特殊设计的枪械,比如侦查步枪(scout rifle,比较著名的例子是斯泰尔斥候步枪),甚至会使用150毫米(5.9英寸)以上适眼距的瞄准镜。戴眼镜者由于眼睛与目镜距离更长,因此有可能需要长适眼距的瞄具。

主镜筒[编辑]

不同的瞄准镜有着不同的主筒尺寸、材料、制造工艺和表面加工。镜筒的外直径通常在19毫米(.75英寸)至40毫米(1.57英寸)之间,但现今市面上最常见的是25.4毫米(1英寸)和30毫米(1.2英寸)两种。镜筒的内直径影响了光线可以通过的面积、镜片等部件可安装的体积,以及仰角和风偏调节的极限。用来做长距离或低光环境下观瞄的瞄准镜通常拥有更粗的镜筒。同时更大的镜筒直径还可以在不牺牲内部空间的情况下增加筒壁厚度,增加整个镜体的耐用性。

标线[编辑]

各种类别的标线
俄制PSO-1瞄准镜的标线
PSO-1标线左下角可以用来估算一个170厘米高目标的距离的标尺

标线(reticle,在英国也称graticule)是瞄准镜上最重要的部分之一,因为它直接为使用者提供了可靠一致的目测参照物。瞄准镜的标线种类很多,从最简单的十字线到可以用来准确估算目标距离、补算子弹下坠和风偏的复杂标尺。利用标线,射手可以校正瞄准角度,也可以估算目标物体的距离和大小。

从制造工艺上来说,瞄准镜的标线主要有丝线式(wire reticle)和蚀刻式(etched reticle)两种。丝线式标线是最老的款式,由金属丝或布丝制成,通常安装在镜筒内合适的位置;蚀刻式标线则是将标线图案直接刻画到镜内的光学部件之中,与瞄准镜的光学系统成为一体。如果加以背景照明,丝线式标线通常会反射一部分照明光,因此不会保持完全黑暗的高对比度;蚀刻式标线则会在背景照明下保持完全黑暗,因此蚀刻式标线更佳。蚀刻式标线还可以提供更加灵活的图案设计,一些制造商甚至提供客户自己设计的特制图案。在高端型号和价码的瞄准镜中,通常是蚀刻式标线一统天下,但是丝线式标线仍然在低端价格的瞄准镜中占有一席之地。

十字线[编辑]

最简单也是最原始的标线是十字线(crosshair),最初是由天然的毛发(其英文名称的来源)、丝线甚至蜘蛛丝制造,现今通常使用可以塑形调整宽度的金属丝或复合材料来制造,或者使用蚀刻在镜片内的墨线。绝大多数现代瞄准镜标线其实都是从十字线基础上衍生出来的设计。

十字线简单廉价、耐用可靠,适合用来瞄准高对比度的简单目标,但是在较细的十字线在复杂背景前会发生看不清的问题。较粗的十字线通常不会失落在复杂背景中,但是会更加遮挡目标图像,并且没有细十字线的精度高。因为这个原因,现代十字线设计通常会使用两种方案来应对:一种是目标点(target dot)或圈标线(circle reticle),也就是在较细的十字线的中心设置一个相对较粗的准心,或在准心周围设置一个同心圆圈,这样即使看不清十字线也有瞄准参照;另一种是重叠十字线(duplex crosshair),也就是使用较粗的十字线但在接近中央的区域改为较细(如同粗细两条线叠加起来一样)来追求精确,而且即使看不清准心也可以用周围的粗线迅速目测到正中位置。

一些重叠十字线还可以用来估算距离,比如“30/30标线”就是在距离准心上下左右30角分的位置改变十字线粗细,这样使用者就能以此为参考估算目标周围的距离。相似的例子还有Leupold制造的16角分重叠十字线,在180米距离时视野中心相对的两条粗线端点的距离为大约83.8厘米;若已知物体大小约为40厘米,在瞄具中的图像占据了端点至端点的空间,那么物体大约在90米的距离外,这样射手就可以补充子弹下坠(通过距离估算)以及补充风偏影响(通过风速仪或旗帜等物品估算)。当然需要注意的是在山坡上射击时有时需要刻意举高或举低,修正时需要知道山坡的斜率。而且单纯依靠没有刻度的十字线去估算弹道,误差会很大,特别是在远距离瞄准时。

密位式标线[编辑]

许多现代瞄准镜标线在设计上都可以利用基线测距(stadiametric rangefinding)原理来估算目标距离,或通过已知距离来估算物体的大小,其中最有名也是最受欢迎的设计就是密位式标线(mil reticle)。而最常见的是密位点标线(mil-dot reticle),也就是在十字线的基础上于距离准心每个毫弧度密位)的间隔位置上布有一个小点[6]让使用者可以在已知目标尺寸的基础上利用密位值反向估算出大概精确的距离,并且用来补算子弹的下坠和风偏度。在北约国家的军方和警方中已经广泛使用密位点及其类似的密位刻度标线(mil-hash reticle),并且统一使用手动调整值为0.1密位的瞄准镜,同时狙击小组中观测手与射击手之间的计算通话也以密位为单位标准。

利用密位点估算距离的数学公式是“目标距离=目标长度或宽度÷目视密位值×1000”,一个尺寸为1米的物体在1000米距离上恰好是占有1密位。举个例子,如果使用者在瞄准镜中看到一个高度为1.8米的物体占了3密位的高度,那么目标距离就是1.8米÷3×1000=600米。

与密位式标线相似的是角分式标线(MOA reticle),也就是在距离准心每个角分的间隔位置上布有一个小点或刻度,在几何学原理上和密位式完全相同的,唯一的差别是刻度间距的标准不同。角分式标线在北美的民用市场比较常见,原因是一角分在100距离上大致等于1英寸(其实是1.047英寸),相比起通常用于计算公制单位的密位式标线,仍然使用旧式英制单位美国民间对角分主观上更加习惯认同一些。

聚焦平面[编辑]

瞄准镜内部设计的示意图,其中L1和L2镜片间的焦点处(红箭头)为第一(前)焦平面,L3和L4镜片间的焦点处为第二(后)焦平面
5倍放大
25倍放大
施密特-本德5-25×56 PM II/LP瞄准镜上使用的基线测距标线
注意:因为是前焦面设计的瞄准镜,标线会随着放大倍数变化也跟着一起被放大

因为瞄准镜是以折射望远镜的原理为基础设计的,因此镜内有两个聚焦平面(focal plane)可以用来放置标线:物镜与正像镜之间的第一焦平面(first focal plane,简称FFP,也称前焦面或物方焦面),以及正像镜与目镜之间的第二焦平面(second focal plane,简称SFP,也称后焦面或像方焦面)[7]。在固定放大倍数的瞄准镜上,标线放在哪个焦平面上都无所谓;但是如果是可变倍数设计的瞄准镜,位于第一焦平面的标线会随着目标图像一起同步放大或缩小,而位于第二焦平面的标线则会忽视目标保持自己的尺寸不变。

在使用测距型标线(比如密位点)的时候。因为标线和目标间的尺寸比例依赖于放大倍数,第二焦平面设计的标线只在一个指定倍数(通常是最大倍数)上才会发挥可靠的瞄准校正作用,一旦倍数改变就会导致标线上的刻度变得不准。因此计算公式必须考虑到倍数差,成为“目标距离=目标长度或宽度÷目视密位值×1000×(当前倍数÷指定倍数)”。第一焦平面设计的标线则没有这个问题,但是因为标线随着放大倍数同步变化,会出现标线变得太粗或太细导致使用者在观瞄的时候无法同时看清目标和标线,特别是在低光环境下。此外,第一焦平面设计的制作成本通常要高于同等质量水平的第二焦平面设计,因此目前市面上绝大多数主流瞄准镜除非特殊标明,基本上都是第二焦平面设计的产品。

虽然通常价码较贵,但是因为使用起来更加方便可靠,越来越多追求精度的射手仍然倾向于第一焦平面的瞄准镜设计。同时为了解决第一焦平面标线在极端倍数过粗过细干扰图像的问题,现在一些厂家已经试着推出新的双焦面(dual focal plane,简称DFP)设计的高端产品,只在第一焦平面放置刻度标码,准心和十字线被挪到了第二焦平面,使用时两个焦平面的图像重叠。这种新设计的成本要远远高于普通的第一焦平面和第二焦平面产品。

标线照明[编辑]

在低光条件下使用时,标线往往会因为整体亮度太低而难以看清,因此就有了照明标线的需求。能够根据使用情况来调节照明的亮度是至关重要的,因为太亮的标线会导致射手的瞳孔收缩使其无法看清目标背景。

标线照明通常是由干电池供电的发光二极管提供的(但也有用其他类型的电子光源),通常由后向前照射在标线上,然后反射到使用者的眼里。因为红光对人眼在低光情况下的影响最少,因此通常使用的都是红光。放射性同位素,比如,也可以被用来作为照明标线的光源,通常可以坚持8~10年才会因为放射性衰变丧失亮度。使用氚光源的著名产品有Trijicon的ACOGELCANC79和Trilux的SUSAT等等。此外,一些产品则使用光导纤维来收集并强化环境光来达到照明效果。

视差校正[编辑]

视差效应的原理,图中十字星所对应的是瞄准镜标线的准心

如果目标图像没有处在与标线一致的光学平面上(目标的焦面在标线的焦面前方或后方),就会出现视差效应。在这种情况下,人眼在目镜后方观察位置的细微变化(比如头部稍有移动)都会导致标线和准星发生移动到目标的不同位置上,使得瞄准时产生误差,影响射击精度。为了应对这个问题,中高端的瞄准镜通常都有视差校正设计,也就是让准镜内部的光学部件可以移动,来调整将标线和目标挪到同一焦面上。视差校正的设计通常有两种:

  • 可调物镜式(adjustable objective,简称AO),用可以移动的物镜来调整前后焦平面与标线重合;
  • 侧面调焦式(side focus,简称SF),用主管侧面(通常是左边)的拨盘移动管内的正像镜来调整前后焦平面与标线重合。一些追求能够细微调校的型号会使用较大直径的波轮,因此也称侧轮式(sidewheel)。这种设计比AO式更复杂、成本更高,价码也更昂贵,但是人机工效更优也更受消费者欢迎,因为使用者不需要改变射击姿态就可以随意进行调整。

在观测较远距离的目标时人眼位置变化产生的视线角度变化,要大大小于观测较近距离目标时的视角变化。如果只用来瞄准远距离目标,瞄准镜即使没有视差校正设计精度也不会太受影响。因此市面上大部分用来打猎的中低端价位瞄准镜通常只设计有一个固定的最佳视差距离(通常在100码),因为打猎距离通常不会超过300码,对远程精度的要求并不是那么严格。一些比赛用或军用的瞄准镜可能会有固定在200或300码的视差设定,在比这个距离稍远或稍近的距离上,即使有细微的视差也通常不会太影响射击效果。但如果是在凸缘底火枪械、气枪手枪霰弹枪前膛枪这类有效射程较短的武器上使用,视差造成的影响就不可小视了。因此这类短程武器上使用的瞄准镜,通常都要求带有视差校正的设计,有些特殊型号甚至可以把视差设置调整到个位数距离。

弹著补助[编辑]

一些为指定型号枪械和弹药所设计的瞄准镜上有弹道补助(bullet drop compensation,简称BDC)的设计,来补助测算平射情况下子弹的飞行下落。这种设计也就是制造厂家在设定一个标准枪口初速空气密度条件下,将子弹在不同目标距离上自由飞行的下落距离预先测试好,并且在瞄准镜的标线上刻画出来,让使用者可以更加方便迅速的估算射击时所需的弹道仰角

因为弹道补助设计依赖于预先假设的外弹道条件,因此通常只对某些指定的枪管-弹药组合有效,如果枪械的型号状况和弹药的口径性能发生了变化,就不再准确了。因为军用制式枪械和弹药的型号搭配通常比较标准化,因此在专门为军用设计的瞄准镜(比如美制的ACOG和苏制的PSO-1)上经常会在标线和调整拨盘上画有预先校对的在特定距离上的弹道补助刻度。在枪械型号和弹药搭配更加多样化的民用市场,弹道补助较为少见,但是如果客户愿意提供枪弹信息一些制造厂家也会提供相应特制的设计选项。同时弹道补助设计基本上不考虑偏离预设条件以外的环境因素,潜在误差在长距离上更为明显,因此通常只用于不太追求极致精度的中近距离射击。追求高精度远程射击的高端射手基本上不会考虑选择弹道补助设计。

调节控制[编辑]

施密特-本德 PM II LP瞄准镜上的手拨调节旋钮

因为瞄准镜其实是有额外特殊功能的折射望远镜,是一种复杂的光学仪器,因此能够细微调控各个部件对发挥所有的潜能来说非常重要。通常在设计上,瞄准镜会有以下的手动调节控制:

  • 目镜焦度(Ocular diopter,也称ocular focus):用来调整标线的聚焦和清晰度。通常处于目镜周围。
  • 仰角(Elevation):用来调整标线和准心的垂直位置。通常处于镜管中央的上方。
    • 现今一些高端瞄准镜会在仰角调整旋钮上设计有“归零”(zero-stop,也称zero reset或turret reset)功能,让使用者可以在将瞄准镜校准后根据自己枪械和使用情况手动将校定的瞄准点锁定为极限,使得在调整仰角时无法将标线调低于锁定点,无论如何拨弄都不会失去归零点。这种设计在长距离射击需要修正瞄准点时非常有用。
  • 风偏(Windage):用来调整标线和准心的水平位置。通常处于镜管中央的右边。
  • 放大倍数(Magnification):用来调整图像的光学放大程度。通常处于目镜管前方与镜管连接的地方。
  • 视差(Parallax):用来调整标线和目标图像的焦面差。通常处于物镜周围(AO式)或镜管中央的左边(SF式)。
  • 照明(Illumination):用来调整标线照明光的强度。通常处于镜管中央左边(如果没有SF式视差调节)或目镜管的上方。

差不多所有现代瞄准镜都有前三个调节控制,第四个必须是可变倍瞄准镜上才能找到,而第五和第六个则属于特殊设计的高端瞄准镜上才会出现的选项。因为调节旋钮属于精密的机械部件,随着时间可能出现积尘、生锈、磨损老化的情况,因此使用过度或过少都会造成问题。

一些老式瞄准镜甚至没有仰角和风偏调节功能,而是依赖特殊设计的镜环或安装基座来提供调节。一些现代的安装基座(比如皮卡汀尼导轨)则特别设计有固定前后高度差(比如前倾20角分、40角分甚至60角分)的款式,来辅助瞄准镜本身进行比较极限的仰角调节,以防对镜体内部的部件造成太大的机械负担。一般来说,可调式基座的适应性更强,但固定倾斜度的基座在面对射击后坐力时更加牢固耐用和可靠。

附件[编辑]

装配在PGM Hécate II狙击步枪上的Scrome LTE J10 F1瞄准镜,目镜配有遮光罩物镜配有翻开式保护盖

瞄准镜通常可以配有的附件包括:

  • 遮光罩(lens hood):安装在镜头外端来遮挡可能干扰图像清晰度的杂光,通常安装在物镜上用来遮挡强烈日光或是清除枪管热气产生的蜃景。一些用有弹性材料制造的遮光罩还可以装在目镜一侧来缓冲后坐力防止镜框撞到射手的眼睛和脸上,并方便射手迅速找到最佳适眼距
  • 保护盖(lens cover,也称lens cap):罩在镜片外部用来保护物镜和目镜不因为裸露在外而受到意外损伤,通常有嵌入式(clip on)、套入式(slide over)和翻开式(flip open)三种。
  • 滤光器(optical filter):可以在不同光线条件下有选择性的过滤所采集到的光谱以便优化图像质量。
  • 蜂巢孔滤光板(honeycomb filter):也称KillFlash®,用来减少物镜反光来防止暴露射手的位置。
  • 防激光过滤片(laser filter):用来保护使用者的眼睛不受外来激光照射伤害,通常在制造时就安装在瞄准镜内部。
  • 拨轮(index wheel):可以替换或套在调节旋钮的外面来方便细微手动调节。
  • 保护套(scope cover):罩在瞄准镜外面来保护整个镜体不受日晒雨淋的外套

光电技术[编辑]

集成式激光测距仪[编辑]

In 1997 Swarovski Optik introduced the LRS series telescopic sight, the first riflescope on the civilian market with an integrated laser rangefinder.[8] The LRS 2-12x50 sight can measure ranges up to 600米(660 yd).[9] The LRS sights are currently (2008) not produced anymore, but sights with similar features are commercially available from several manufacturers.

弹道辅助仪器[编辑]

An integrated ballistic computer/riflescope system known as BORS has been developed by the Barrett Firearms Company and became commercially available around 2007. The BORS module is in essence an electronic Bullet Drop Compensation (BDC) sensor/calculator package intended for long-range sniping out to 2,500米(2,700 yd) for some telescopic sight models made by Leupold and Nightforce. To establish the appropriate elevation setting the shooter needs to enter the ammunition type into the BORS (using touch pads on the BORS console) determine the range (either mechanically or through a laser rangefinder) and crank the elevation knob on the scope until the proper range appears in the BORS display. The BORS automatically determines the air density, as well as the cant or tilt in the rifle itself, and incorporates these environmental factors into its elevation calculations.[10]

The SAM (Shooter-supporting Attachment Module) measures and provides aiming and ballistic relevant data and displays this to the user in the ocular of the Zeiss 6-24x72 telescopic sight it is developed for.[11] The SAM has different sensors integrated (temperature, air pressure, shooting angle) and calculates the actual ballistic compensation. All indications are displayed in the ocular. It memorizes up to 4 different ballistics and 4 different firing tables. So it is possible to use 1 SAM with 4 total different loads or weapons without an additional adjustment.

感光耦合组件和液晶显示技术[编辑]

A totally different approach has been applied in the ELCAN DigitalHunter Digital Rifle Scope series which combines CCD and LCD technology with electronic ballistics compensation, automatic video capture, 4 field selectable reticles and customizable reticles. In 2008 a DigitalHunter DayNight Riflescope that uses infrared light captured by the CCD to enhance low light capabilities became available. It is also possible to attach infrared light sources to use this telescopic sight as an active night sight in total darkness, though the image quality, and overall performance is poor. Some jurisdictions however forbid or limit to use of night vision devices for civilian or gun aiming use.

安装[编辑]

柯尔特蟒蛇左轮手枪上后期装配的瞄准镜

As very few firearms come with built-in telescopic sights (military designs such as the Steyr AUG, SAR 21 and the H&K G36 being exceptions) mounting a scope to a firearm requires additional equipment. Equipment is available to mount scopes on most production firearms. A typical scope mounting system consists of two parts, the scope base and the scope rings. By picking the appropriate combination of scope base to fit the firearm and scope rings to fit the scope, a wide range of scopes may be mounted to most firearms. With the appropriate combination of adjustable scope bases and scope rings it is also possible to mount several telescopic sights on the same gun to make the gun more versatile. However, it is important to take into consideration whether or not a gun is particularly hard to mount. If it is or if a gun is intended for long-range shooting, it could be that the amount of vertical adjustment range is smaller than required. This can be solved with the help of a vertically canted base or canted rings. Typical cant angles offered by mounting components manufacturers are 20 and 30 MOA.

准镜基座[编辑]

The base is attached to the rifle, usually with screws, and is often designed to have a low profile, and to allow use of the iron sights if the scope is not present. Some manufacturers provide integral bases on many of their firearms; an example of such a firearm is the Ruger Super Redhawk revolver. The most commonly encountered mounting systems are the 3/8 inch (9.5 mm) and the 11 mm dovetail mounts (sometimes called tip-off mounts), commonly found on rimfires and air guns, the Weaver type base and the STANAG 2324 (MIL-STD-1913 "Picatinny rail") base. Ruger uses a proprietary scope base system, though adapters are available to convert the Ruger bases into Weaver type bases. Scope base and mounting systems are also manufactured in Europe. Specialized manufacturers like Ernst Apel GmbH[12][13] offer an elaborate program of mounting solutions for many different guns. Some of the European mounting solutions are virtually unknown and hence rarely applied in America. Many European gun manufacturers also developed and offer proprietary scope base systems for their guns, for example Sako has tapered dovetails and Tikka uses 16mm dovetail.

准镜调整环[编辑]

In addition to needing the right type of connector to attach to the desired base, scope rings must be used to hold the scope to the mount. The rings must be of the proper size to fit the scope; common sizes are .75英寸(19.05 mm), 22 mm(0.87英寸), 1英寸(25.40 mm), 26 mm(1.02英寸), 30 mm(1.18英寸), 34 mm(1.34英寸) and 40 mm(1.57英寸). Red dot sights commonly are found in larger sizes, such as 40 mm, and these often use ringless mounting systems designed to fit dovetail or Weaver type bases. Rings are also available in a variety of heights and materials. Ring height is chosen to place the scope high enough to clear the firearm, and at a height comfortable for the shooter.

准镜导轨[编辑]

European telescopic sight manufacturers often offer the option to have mounting rails underneath the riflescope to provide for mounting solutions that do not use scope rings or a single scope ring around the objective of the scope. These rails are an integral part of the scope body and can not be removed. The mounting rail permits the riflescope to be securely and tension-free mounted at the preferred height and correct distance from the shooter's eye and on different guns.

There are several mounting rail systems offered:

The traditional standard prism mounting rail system requires to have the scope rail drilled from the side for fixture screws. The more recent propriety systems mainly offer aesthetic advantages for people who have problems with redundant drill holes in sight in case the riflescope is used on different guns. To avoid drilling the scope rail, the propriety rail mounting systems have special shape connections machined in the inside of the rail. These shape connections prevent ever showing any exterior damage from mounting work on the rifle scope. The propriety rail systems use matching slide-in mount fasteners to connect the riflescope to the gun. Some propriety rails also offer the possibility to tilt the scope up to 1° to the left or right.

导轨界面系统[编辑]

安装在PGM 338 Mini-Hécate狙击步枪机匣上方皮卡汀尼导轨上的施密特-本德 PM II瞄准镜

For mounting telescopic sights and/or other accessories to guns several rail interface systems are available to provide a standardized mounting platform. Probably the best known rail interface system is the Picatinny rail or STANAG 2324 rail or MIL-STD-1913 rail used by NATO forces and other official and civil users. The name of this interface system, which dates back to 3 February 1995, comes from the Picatinny Arsenal in New Jersey, where it was originally tested and was used to distinguish it from other rail standards at the time. The Picatinny rail comprises a series of ridges with a T-shaped cross-section interspersed with flat "spacing slots". Telescopic sight mounting rings are mounted either by sliding them on from one end or the other; by means of a "rail-grabber" which is clamped to the rail with bolts, thumbscrews or levers; or onto the slots between the raised sections.

Another commercially available rail interface system is the Weaver rail mount from Weaver Optics. The only difference between the Picatinny rail and the Weaver rail is the size and spacing of the slots, although almost all rail-grabber-mounted accessories are manufactured such that they can mounted on either type of rail.

The NATO Accessory Rail (or NAR), defined by the new modernization agreement STANAG 4694 approved by NATO on 8 May 2009, is a new rail interface system standard for mounting auxiliary equipment such as telescopic sights, tactical lights, laser aiming modules, night vision devices, reflex sights, foregrips, bipods, and bayonets to small arms such as rifles and pistols.[14] The NATO Accessory Rail is backwards-compatible with the STANAG 2324 or MIL-STD 1913 Picatinny rail.

安装问题[编辑]

Scopes for use on light-recoiling firearms, such as rimfire guns, can be mounted with a single ring, and this method is not uncommon on handguns, where space is at a premium. Most scopes are mounted with two rings, one in the front half of the scope and one on the back half, which provides additional strength and support. The heaviest-recoiling firearms, such as Thompson Center Arms Contender pistols in heavy-recoiling calibers, will use three rings for maximum support of the scope. Use of too few rings can result not only in the scope moving under recoil, but also excessive torque on the scope tube as the gun rolls up under recoil.

Scopes on heavy-recoiling firearms and spring piston airguns (which have a heavy "reverse recoil" caused by the piston reaching the end of its travel) suffer from a condition called scope creep, where the inertia of the scope holds it still as the firearm recoils under it. Because of this, scope rings must be precisely fitted to the scope, and tightened very consistently to provide maximum hold without putting uneven stress on the body of the scope. Rings that are out of round, misaligned in the bases, or tightened unevenly can warp or crush the body of the scope.[15]

Another problem is mounting a scope on a rifle where the shell is ejected out the top of the action, such as some lever action designs. Usually this results in the scope being offset to one side (to the left for right-handed people, right for left-handed) to allow the shell to clear the scope. Alternately a scout rifle type mount can be used, which places a long-eye-relief scope forward of the action.

A firearm may not always be able to fit all aiming optics solutions, so it is wise to have a preferred aiming optics solution first reviewed by a professional.

用途[编辑]

狙击步枪瞄准镜中观测美国海军陆战队汉森营训练场
装配了亨索尔特4×24 M1瞄准镜的瑞典AK4OR自动步枪
德制G36A1突击步枪上装配的附加反射红点的ZF 3×4°双重战斗瞄具系统

Telescopic sights have both advantages and disadvantages relative to iron sights. Standard doctrine with iron sights is to focus the eye on the front sight and align it with the resulting blur of the target and the rear sight; most shooters have difficulty doing this, as the eye tends to be drawn to the target, blurring both sights. Gun users over 30 years of age with keen eyesight will find it harder to keep the target, front sight element and rear sight element in focus well enough for aiming purposes, as human eyes gradually lose focusing flexibility with rising age, due to presbyopia. Telescopic sights allow the user to focus on both the crosshair and the target at the same time, as the lenses project the crosshair into the distance (50 m or yd for rimfire scopes, 100 m or yd more for centerfire calibers). This, combined with telescopic magnification, clarifies the target and makes it stand out against the background. The main disadvantage of magnification is that the area to either side of the target is obscured by the tube of the sight. The higher the magnification, the narrower the field of view in the sight, and the more area is hidden. Rapid fire target shooters use reflex sights, which have no magnification; this gives them the best field of view while maintaining the single focal plane of a telescopic sight. Telescopic sights are expensive and require additional training to align. Sight alignment with telescopic sights is a matter of making the field of vision circular to minimize parallax error. For maximum effective light-gathering and brightest image, the exit pupil should equal the diameter of the fully dilated iris of the human eye — about 7 mm, reducing with age.

军用[编辑]

Though they had been used as early as the 1850s on rifles, and even earlier for other tasks, until the 1980s, when optical device and assault rifle combinations such as the Austrian Steyr AUG and the British SUSAT mounted on the SA80, became standard issue, military use of telescopic sights was restricted to snipers because of the fragility and expense of optical components. Additionally the glass lenses are prone to breakage, and environmental conditions such as condensation, precipitation, dirt, and mud obscure external lenses. The scope tube also adds significant bulk to the rifle. Snipers generally used moderate to high magnification scopes with special reticles that allow them to estimate range to the target. Since the 1990s many other armed forces have adopted optical devices for general issue to infantry units and the rate of adoption has increased as the cost of manufacture has fallen.

Telescopic sights provide some tactical disadvantages. Snipers rely on stealth and concealment to get close to their target. A telescopic sight can hinder this because sunlight may reflect from the lens and a sniper raising his head to use a telescopic sight might reveal his position. The famous Finnish sniper Simo Häyhä preferred to use iron sights rather than telescopic sights to present less of a target. Harsh climate can also cause problems for telescopic sights as they are less rugged than iron sights. Many Finnish snipers in WWII used iron sights heavily because telescopic sights did not cope with very cold Finnish winters.

The market for military telescopic sights intended for military long-range shooting is highly competitive. Several high end optics manufacturers are constantly adapting and improving their telescopic sights to fulfill specific demands of military organizations. Two European companies that are active this field are Schmidt & Bender and Zeiss/Hensoldt. American companies that are also very active in this field are Nightforce, U.S. Optics Inc. and Leupold.[16] These high end sighting components generally cost €1500 / $2000 or more. Typical options for military telescopic sights are reticle illumination for use under adverse light circumstances and the presentation of scope settings or ballistic relevant environmental measurements data to the operator through the sights ocular.

The former Warsaw Pact members produce military telescopic sights for their designated marksmen and developed a range finding reticle based on the height of an average human. This stadiametric rangefinder reticle was originally used in the Russian PSO-1 4×24 rifle scope and is calibrated for ranging a 1.7 m tall target from 200 m to 1000 m. The target base has to be lined up on the horizontal line of the range-finding scale and the target top point has to touch the upper (dotted) line of the scale without clearance. The digit under which this line up occurs determines the distance to the target. The PSO-1 basic design and stadiametric rangefinder are also found in the POSP and other telescopic sight models.

The Israeli military began widespread use of telescopic sights by ordinary infantrymen to increase hit probability (especially in dim light) and extend effective range of standard issue infantry rifles. Palestinian militants in the al Aqsa Intifada likewise found that adding an inexpensive scope to an AK-47 increased its effectiveness.

Today, several militaries issue telescopic sights to their infantry, usually compact, low-magnification sights suitable for snap-shooting. The US military issues the Advanced Combat Optical Gunsight (ACOG), designed to be used on the M16 rifle and M4 carbine. American soldiers in Iraq and Afghanistan frequently purchase their own combat optics and carry them from home. The British army fields the SA80 rifle with the SUSAT 4× optical sight as standard issue. The Canadian Forces standard C7 rifle has a 3.4× Elcan C79 optical sight. Both Austria and Australia field variants of the Austrian Steyr AUG which has built an integral 1.5× optical sight since its deployment in the late 1970s. The German Army G36 assault rifles have a more or less built in dual combat sighting system consisting of a ZF 3x4° telescopic sight combined with an unmagnified electronic red dot sight. The dual combat sighting system weighs 30 g(1.1 oz) due to a housing made out of glass fibre reinforced polyamide. All German G36 rifles are adapted to use the Hensoldt NSA 80 II third-generation night sight, which clamps into the G36 carry handle adapter in front of the optical sight housing and mates with the rifle's standard dual combat sighting system.

参见[编辑]

外部連結[编辑]