牛反光轴校准详细步骤

自从入了小黑后，一直很头疼光轴，我想这也是很多爱好者头疼的事。近期找到一篇很好的外文，翻译一下供大家参考，翻译不好的地方还望轻拍

原文链接：http://www.astro-baby.com/astrob ... ewtonian-reflector/

好了，废话不多说，上好文。

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One of the toughest jobs a beginner has to learn is Newtonian telescope collimation.
This needs to be carried out relatively frequently on Newtonian Reflector type telescopes and
it can be a very scary and/or frustrating experience for a beginner using a collimator.

牛顿反射式望远镜经常需要进行光轴校准，然而对于刚踏入天文观测的爱好者来说，光轴校准就像是一场噩梦，
是一个比较棘手却又不得不面对的事。

This guide will take you through the various steps towards perfect collimation.
I have included both diagrams to show you the ideal as well as pictures showing how it will actually look
as beginners are often confused between the idealised views of a well collimated telescope and the views
they are seeing with their own equipment.

本文将详细描述完美光轴校准的各个步骤，并通过图表和图片展示完美校准时的情形和校准操作时从设备上看到的情形，
而这通常是初学者容易混淆的地方。

The scope being collimated in these pictures is a Sky-Watcher 200P with an aperture of 200mm and a focal
length of 1000mm (Focal Ratio f 5).This is a common enough fast reflector and the collimation process is
essentially the same for any Newtonian telescope. Where there are differences between a fast scope and
a slow (high f number) scope I have provided text and pictures to highlight the differences.

本文校准使用的望远镜是Sky-Watcher 200P，其口径为200mm，焦距为1000mm，即焦比为5(常见的快镜)。
本质上其校准过程与其他任何牛顿望远镜一样，当然，也有一点区别，文中会以高亮的方式加以区别和强调。

Fast telescopes are typically of around f5 to f3 or even faster.
You can calculate the focal ratio of your own telescope by the simply dividing the focal length by the diameter
of the primary mirror. The Sky-Watcher 200P has a focal length of 1000mm and a primary mirror diameter of 200mm
so 1000 divided by 200 = 5 ( focal ratio ). Slow telescopes are usually at f6 – f7 or slower.

通常快镜焦比在f5至f3，甚至更快。主镜焦距除以主镜口径即为焦比。例如，Sky-Watcher 200P 焦距为1000mm，口径为200mm，
因此焦比=1000/200=5。慢镜焦比通常为f6-f7，甚至更慢。

To accurately collimate with this guide you will need a Cheshire collimator and a collimation cap.
My own collimation cap is made from a focuser blanking cover with a small hole drilled through the exact centre.
You can make a collimation cap from a 35mm film container or buy them ready made.

为了精确校准，你需要一个Cheshire collimator(不清楚怎么翻译，后面有图)和一个collimation cap(不清楚怎么翻译，后面有图)，
就是一个中心有小孔的东西(类似光轴终结者)。

I have not covered collimation with a laser because my own experience has been lasers seem to create more problems than
they solve as they also require collimation which isn’t always possible with some low cost lasers.
Lasers generally only work well in telescopes which have a high quality focuser with minimal ‘slop’.
The average mass produced telescope very often has a focuser that is too imprecise to make use of a laser.

本文没有涉及使用激光校准器进行校准的相关内容，因为就我使用激光校准器的经验来看，如果是一个廉价的激光校准器，其本身就需要校准，
因此在校准过程中其产生的问题比解决的问题还多。激光校准器通常仅在具有高质量调焦器的望远镜上工作良好。
一般望远镜的调焦器精度往往不足以支持使用激光校准器进行校准。

This guide may look scary – if you take it one step at a time its not that hard.
In order to cover off all of the issues the guide is somewhat larger than some others on the web – many guides
omit various details which can lead to confusion and frustration in the beginner.

本文看起来有点冗长。为了涵盖校准过程中的各种问题，本文可能比其他介绍光轴校准的文章长，但是，如果一步一步操作也不是那么困难。
许多文章由于忽略了各种细节反而会给初学者带来困难。

To collimate the telescope it should be aimed towards a bright but not glaring surface such as a well lit pale painted
wall or fabric in order to get a good image in the telescope and the Chesire should be arranged so that its
shiny angled surface gets a good light.​ Cheshire @ Amazon

为了校准望远镜，必须把望远镜对准一个明亮但不耀眼的平面，例如一面白墙或建筑，以便从望远镜中获得较佳的图像。
同时准备Chesire以使其光滑斜面能够获得足够的光线。



Tips before you start …..
开始前的一些建议：

Rule 1 – Before starting collimation don’t assume that anything is out of kilter and check each element before
adjusting anything. About 90% of collimation errors are down solely to the primary mirror so don’t jump in and
start meddling with the secondary unless you are sure that there is a problem.
Each stage of this guide will show you how to check the various elements – only if they are out of alignment
will you need to make adjustments.

建议1 - 在开始校准前要先检查下每个组件而不要假设所有组件都有问题。通常90%的光轴问题仅仅是因为主镜，
所以不要一开始就乱动副镜除非确定副镜需要调整。本文中，每个校准阶段会先告诉你如何检查各个组件，
仅当这些组件不在正确的位置时才需要进行调整。

Rule 2 – Make sure you have all of the tools you require ready to hand.
Some telescopes will require Allen keys and a screwdriver.
You don’t want to be looking for tools when you halfway through collimation.

建议2 - 确保已准备好需要的所有工具。有些望远镜需要六角扳手和螺丝刀。在校准的中途确保所有工具随手可拿。

Rule 3 – Make sure you have budgeted for enough time. Collimation can be a very time intensive process for a beginner. It can be carried out over successive sessions if you need to but don’t plan on collimating on a night when you want to be observing. It will lead to a rush job and frustration – TAKE YOUR TIME and you will be rewarded with good collimation and better viewing through your telescope.

建议3 - 确保已安排了足够的时间。对初学者来学，光轴校准是一个非常耗时的过程。在某个晚上进行观测时可能需要进行校准，而这并不在计划之列，此时进行校准将会相当匆忙且容易出错。专门花点时间进行校准，在观测时望远镜会回报给你完美观测图像，这是值得的。

Rule 4 – Do not over-tighten nuts and adjusters.
They need to be firm and tight – they DON’T need to be tightened until the threads pop.

建议4 - 不要过度拧紧螺母和调节螺丝，只需上紧即可，切勿拧到螺纹极限。

Rule 5 – Whenever you are working on a telescope ALWAYS work with the telescope tube in a horizontal position.
If you drop things into the tube you don’t want them to impact on the primary mirror.
I also wear cotton gloves when I am working to make sure I don’t damage anything with sweat from my hands.

建议5 - 任何时候调整望远镜，确保望远镜处于水平位置。如果有东西不小心掉进镜筒，你肯定不希望它们碰到主镜。
当我操作时我还会戴上棉质手套以避免汗水破坏任何东西。

Collimation Step 1 – The Spider Vanes and Secondary Mirror Holder
校准步骤1 - 蜘蛛架和副镜座

Before attempting to collimate the secondary mirror it’s essential to get the mirrors holder central to
the tube and the primary mirror. Some scopes allow adjustment of the spider vanes.
If your scope has this facility you need to check whether the secondary mirror holder is held perfectly central
by the spider vanes.

在尝试校准副镜之前，首先要确保副镜座位于镜筒和主镜的正中央。某些望远镜允许调整蜘蛛架，
如果你的望远镜有这个功能则需要检查(或调整)蜘蛛架以使副镜座位于镜筒正中央。

Note: Some scopes require the secondary mirror to be offset from the centre of the tube.
This in itself raises questions. Some telescopes will have the secondary offset on its holder
in which case the centre of the vanes should be centred to the tube while other manufacturers
will opt for the vanes centre point being off centre. The offset on most scopes will be in millimetres and
wont affect collimation by much. You should check whether your telescope requires offsetting with the manufacturer
or supplier. If you cannot get an answer assume that the mirror holder is to be central to the telescope tube.

注意：某些望远镜要求副镜适当偏离镜筒中央，这本身就引发了系列问题。某些望远镜已经对副镜在副镜座上进行了偏轴，
这种情况下，蜘蛛架的中心必须位于镜筒中心。然而，某些生产商可能选择让蜘蛛架的中心偏离镜筒中心。
在多数望远镜上，偏移量一般只是几毫米，不会对校准产生过大影响。你必须和生产商或供应商确认你的望远镜是否需要对副镜进行偏轴处理。
如果不能确定的话，可以假设副镜座必须位于镜筒中心。

There are two methods to accomplish getting the mirror holder central to the tube.
The first is relatively simply which is to measure the distance between the tube and the secondary mirror holder
along each of the vanes. The distance should be identical for each vane.
If the vanes are not equal than adjust them using the vanes attachment / adjustment screws.
The cross head on the central screw makes an ideal reference point.

有两种方法来调整副镜座居中。第一种方法是在每个蜘蛛腿上测量副镜座到镜筒壁的距离。每个距离必须完全相同，否则使用调节螺丝进行调节。
副镜座中间的调节螺丝是一个很好的参考点。




The second method for aligning the mirror holder is a little more complex but more accurate and easier once
the initial work is done.
Cut a piece of card out which is the same diameter as the telescope tube and drill a small hole in its centre.
To find centre on the circular piece of card fold the card into quarters.
The point where the folds cross is the centre. Now look through the hole and the central screw on the secondary
mirror holder should be exactly underneath. If it isn’t adjust the spider vanes until it is.
This provides a simple and reliable method of getting the mirror holder central and once you have made
the piece of card future centering of the vanes will be easier.
To adjust the vanes you will need to slacken the screws and then slowly tighten them in turn to pull
the mirror holder to the centre.

第二种方法有点复杂但是精度更高，如果已做了初始工作，其实也很简单。剪一个和镜筒一样大的卡片并在其中心开一个小孔。
两次对折卡片很容易找到其中心。现在从小孔看过去，副镜座中央的调节螺丝应该就在其后面。否则，调节蜘蛛架调节螺丝。
这种方法简单可靠，而且一旦把卡片做好了，以后调节会更方便。

调节蜘蛛架时，首先松开调节螺丝然后慢慢的依次锁紧它们直到将副镜座居中。

Collimation Step 2 – The Secondary Mirror / Focus Tube Alignment
校准步骤2 - 副镜/调焦筒对齐

The hardest stage of collimation is the secondary mirror alignment.
This is almost always very time consuming but once done should not need readjustment unless the scope is
severely shaken or dropped or the vanes and the secondary are removed for any reason.

校准最困难的部分就是副镜对齐。这通常是最耗时的步骤，但是一旦调教完成则不再需要重新校准，
除非望远镜被严重振动或是跌落或是由于其他原因导致蜘蛛架和副镜移动。

The easiest method to align the secondary mirror is with either a collimation cap or a sight tube.
With my Sky-Watcher 200P I find a collimation cap is the better solution as a sight tube or my Cheshire do not
allow me to see the very edges of the secondary mirror through them.

对齐副镜最简单的方法是使用一个collimation cap或瞄准筒。以我的Sky-Watcher 200P为例，
我发现相对于瞄准筒或Cheshire，collimation cap是最佳的选择，因为使用其它校准器我无法清楚地看到副镜的边缘。

Idealised view through the focus tube
调焦筒下的完美视图



The first object of secondary mirror alignment is to get the secondary mirror directly under the focus tube and
appearing as a circle. The secondary mirror is an elliptical shape but when presented to the focuser at
the correct angle will appear as a perfect circle.
副镜对齐要做的第一件事是将副镜置于调焦筒的正下方，且通过调焦筒看为一个圆。副镜虽为椭圆形状，但是通过调焦筒从正确的位置观看时，
其呈现为完美的圆形。

Many people find the reflections in the mirrors confusing and in truth it can make this stage of the process quite
hard as your eyes can be confused by the multiple reflections between the secondary and primary mirrors which can
create a kind of optical illusion which can make it hard to assess whether the view is circular or elliptical.

很多人发现副镜中的各种反射像非常容易混淆，事实上，这可能会导致校准难以进行，因为副镜和主镜间的多重反射像会混淆视场，
其能够产生一种光学错觉以至于很难判断视场究竟是圆还是椭圆。

A simple solution is to use a piece of white card or paper to block the primary mirrors reflections.
Simply insert a piece of white paper into the telescope tube between the secondary and the primary mirrors.
This will create a view of the secondary as just a white circle. Another tip here is that it’s often quite hard to
see whether the secondary is presenting as a circle against the black background of the tube.
I insert a piece of coloured card or paper behind the secondary which allows my eyes to more readily detect whether
the secondary is appearing as a circle and is centred to the dark circle created by the edge of the focuser.

一个简单的解决办法是使用一张白色卡片或纸以阻断主镜反射。在副镜和主镜之间简单插入一张白纸。这样，视场中副镜将仅仅是一个白色的圆。
因为很难在镜筒黑色的背景下判断副镜是否呈现为圆面，另一个建议是在副镜下方插入一张有颜色的卡片或纸，
这样，会更容易判断副镜是否呈现为圆面且位于由调焦筒边缘产生的黑色圆环的中间。



If the secondary is not centred under the eyepiece you will need to adjust it using the centre screw of
the secondary holder.

在视场中，如果副镜不在中心，则需要通过副镜座中间的调节螺丝进行调整。

This is shown below. You are advised to have the telescope tube near the horizontal position
while you carry out this work in order to ensure that if there is an accident the secondary doesn’t fall down
the tube and into the primary mirror. Keep a hand holding or supporting the secondary mirror holder without
touching the mirror surface itself. Proceed with great care and caution and take your time.
The adjuster screw is quite coarse and the mirror will move quite a lot with each turn.
Be careful not to loosen the screw too much which will cause the secondary to disengage from its holder and fall off.

为了确保安全以防止副镜跌落镜筒因而破坏主镜，建议在调节时将望远镜调整至水平状态。用手握住副镜座但不要碰到副镜镜面。
千万小心且需要耐心，调节螺丝精度很低，每旋转一点可能会产生较大的位移。不要将螺丝松动太多以防止副镜从副镜座脱离并跌落。

Adjusting the secondary mirror centre screw
调节副镜中心螺丝



The centre screw adjusts the secondary mirror both up ( away from the primary mirror ) and
down ( towards the primary mirror. To adjust this you may have to loosen the screws or Allen keys which control
the tilt of the secondary mirror. These are also visible in the picture to the left.
Be careful not to apply too much force and go slowly.

副镜座中心螺丝用于调整副镜高低(远离主镜或靠近主镜)。为了进行调整，首先应松开控制副镜倾角的螺丝，动作缓慢且不要太用力。

Simple collimation cap on focus tube

Then use a collimation cap in the focuser to force your eye central to the focus tube and rack the focuser tube
as far out as possible.
Now move the mirror up or down the tube using the central adjusting screw on the mirror holder until you have
the secondary mirror centred.

然后将collimation cap放入调焦座以确保眼睛位于调焦筒的中间，并通过调焦将其调焦至足够远。现在调节副镜座中央螺丝移动副镜，
直到副镜居中。

You will also need to rotate the mirror until it presents as good a circle in the focuser as possible and adjust
the tilt screws to to achieve a good circular shape on the secondary.

同时还需要旋转副镜，直到在视场中其呈现为一个近乎完美的圆面，最后调节副镜倾角螺丝使之呈现为完美的圆。



You should eventually get to a view which is similar to that shown on the left – this view is not perfect as it
was taken with a small digital camera but it should serve as a rough guide as to how things should be looking
if you have adjusted the secondary correctly.
Once the mirror is aligned correctly under the focuser lightly tighten the tilt screws.

最后，你视场中的影像将非常类似于下图。该图使用一个小数码相机拍摄，虽然不是那么完美。但作为一个粗略的向导以展示是否已调节好还是足够的。一旦副镜正确对齐调焦筒，轻轻锁紧倾角调节螺丝。



You can now proceed to the second stage of the secondary alignment which is aligning the secondary
to the primary mirror

下面可以进行副镜对齐调整的第二阶段，将副镜和主镜对齐。

Collimation Step 3 – The Secondary Mirror/Primary Mirror Alignment
校准步骤3 - 副镜/主镜对齐

Aligning the secondary mirror to the primary is easily the hardest task. Still using the collimation cap in the
focuser you now align the secondary using its tilt adjusters and occasionally a slight amount of rotation on
its main centre screw ( you may need to loosen the screw tightly and twist the secondary mirror round by grasping
its holder – DO NOT TOUCH THE MIRROR ITSELF ) to get the secondary centred onto the primary.
This process is covered in the pictures below.

对齐副镜和主镜显然是最困难的任务。仍然使用collimation cap，现在通过副镜倾角螺丝进行调整，可能也会需要轻微地旋转中央调节螺丝(轻微地松开中央螺丝并抓住副镜座旋转副镜，注意，不要碰到镜面)以使副镜主镜完全对齐。



First remove the coloured card and the white ‘baffle’ card in the telescope tube.
Now look into the collimation cap and using the tilt screws get all of the primary mirrors retaining
clips into view and at the edge of the secondary mirror.  IGNORE ALL OTHER VISUAL INFORMATION !  
All you are trying to do at this stage is get the secondary mirror centred on the primary mirror.

首先移除之前放置在镜筒中的彩色卡片和白色卡片。然后通过collimation cap观察并使用倾角调节螺丝进行调节，
使主镜的所有固定爪出现在视野中并位于副镜边缘。忽略所有其他可视信息！本阶段要做的仅仅是使副镜主镜对齐。



This diagram shows the classic view of the mirror clips showing in the secondary mirror which are equally spaced
and equally proud. Not all scopes will have three mirror clips – larger scopes maye have 6 or even eight.
It may be that to achieve this view the tilt screws alone may not be enough and you may have to
apply a small amount of rotation to the secondary mirror by slackening slightly the centre screw and
applying a small amount of rotation to the mirror.
Don’t worry about this as it may just show that your visual check was ‘off’ by a small amount.
In the diagram above there is a circle marked in yellow. This is the likely extent of your view
if you are using a Cheshire eyepiece at this stage.
I personally prefer a collimation cap which provides a slightly wider view of the secondary.

上图是主镜固定爪在副镜中的典型视场，其是均匀分布的。并不是所有的望远镜都有三个主镜固定爪，大型望远镜可能有6个甚至8个。
为了调节至图中的这种状态，仅仅调节倾角螺丝可能还不够，还需要轻微地松开中央螺丝并旋转副镜。

在上图中有一个黄色的圆，这是使用Cheshire目镜时的视场环，我更喜欢collimation cap，其能提供稍微比副镜大一点的视场。



This photograph shows what the actual view should be like at this stage of the process.  
Note the three mirror clips are all visible and are all equally close to the edge of the secondary mirror and
the secondary is showing round and centred to the focuser tube ( the dark area at the edges of the picture)
You may need to move your focuser in or out to achieve a good view but the image should be very similar to
this photograph.

这张照片展示了本阶段调节过程中的实际视场。注意三个主镜固定爪都可见且等距且靠近副镜边缘，
而且副镜显示为圆面且位于调焦筒(照片边缘的黑色区域)中间。你可能需要结合调焦以获得一个好的视场，但是不管怎么样，
看到影像应该非常类似这张照片。
When all three clips are in view (and some scopes may have more clips) and shown at the edge of the secondary mirror
with equal space around them this part of the collimation process is complete.
Tighten down the tilt adjusters and take a final check.

当所有三个主镜固定爪(某些望远镜可能更多)同时出现在视场中且等距位于副镜边缘时，本阶段校准完成。锁紧倾角调节螺丝并最后检查一遍。

The tilt adjusters can be set quite tight but be careful not to apply too much force and bend the spider vanes.
As with the previous step its best to have the telescope horizontal during this step in case an Allen key is
dropped into the tube.

完全锁紧倾角调节螺丝但不要过分用力以免弯曲蜘蛛架。如前所述，调节过程中最好将望远镜置于水平状态以防止六角扳手掉落镜筒。

Once the primary mirror clips are shown reflected in the secondary and the tilt screws have been tightened
take a final check using the procedures in stage 2 that the secondary still shows as centred and circular.

一旦主镜固定爪反射像处于副镜中且锁紧了倾角调节螺丝，使用阶段2的方式重新检查一遍以确保副镜依然处于对齐状态。

If the secondary has shifted then you will need to realign using the procedures in stage 2 and then run through the procedures in stage 3 again. Its not uncommon for some rotation error to creep into the mirrors position while the tilt screws are adjusted. Take your time, be patient and continuously go back over your work and make sure all is well at each stage before continuing.

如果副镜发生了偏移，那么就需要按阶段2的方式重新调节然后再执行阶段3。通常，在调节倾角螺丝时可能会引入一点误差。花点时间和耐心重复之前的步骤，在开始下一步之前确保每个步骤都完美完成。

When you are satisfied that the mirror is centred and true as in step 2 AND all the mirror clips from the primary are in view as per step 3 you can now tighten the adjusters down, these need to be firm but do not apply so much force that you strip threads. A standard Allen key is best rather than an Allen headed screwdriver or a multi tool as it will limit the force you can apply. Take care also that you do not apply too much force and cause the spider vanes to bend.

当调节满足步骤2中描述的副镜对齐状态以及步骤3中主镜固定爪都在视野中时，这时可以锁紧调节螺丝，但不可用力过度。

Now you should check using a small mirror that the secondary adjustment is more or less equal and that
no one screw is causing the mirror to be canted too far over as per the diagrams below.

现在，你需要准备一个小镜子以检查副镜调节量是否大致相等，且没有螺丝导致副镜倾斜过度。


Collimation Step 4 – Aligning the Primary Mirror
校准步骤4 - 主镜对齐

The final step in collimation is the primary mirror. This is relatively simple to carry out and the cause of
most ‘in the field’ collimation errors.

校准的最后一步是主镜校准。这一步相对简单但也是多数校准误差的根源。

At the rear of the telescope you will find three pairs of screws.
These are the primary mirror tilt adjusters and their respective lock nuts.

在望远镜的后端有三对调节螺丝。它们是主镜的倾斜调节器以及相应的锁紧螺丝。

Note: Some telescope manufacturers (Sky-Watcher for instance) cover the collimation adjusters with a steel plate.
This will need to be removed before collimation can proceed.

注意：某些望远镜生成商(例如信达)会用一块钢板盖住校准调节器，因此，在开始校准之前将其移除。



For this stage you will need the Cheshire collimator. Insert this into the focuser and take a look
through the collimator. You should see a pattern similar to the one shown below right – this is from
a telescope that is in collimation.

在本阶段，你需要一个Cheshire校准器，将其插入调焦筒并通过其进行观察、校准。你应该看到如下右图的模式：



It may be that that the pattern is offset and will show the cross hairs as being adrift from the central
circle created by the Primary Mirrors centre spot and that the centre spots are adrift.
If this is so then you will need to adjust the primary mirror.

可能你看到的模式已发生偏移，十字丝与主镜中心点对应的圆环已发生偏移，这时就需要调节主镜。



If collimation of the primary mirror is required loosen the lock screws off and adjust the primary mirror
using its adjuster screws until you see a pattern as per the diagrams and pictures below.

如果需要调节主镜，松开锁紧螺丝然后调节主镜调节螺丝直到看到如下所示的图片。

Take care when using the adjuster screws that you do not allow the mirror to come too far forward on
adjustment as the screws may disengage and also take care that the collimation screws and lock screws
aren’t tightened down to a point which may cause the primary mirror to become ‘pinched’ or distorted.
They should be finger tight only.

调节时防止螺丝脱落或锁紧螺丝过紧导致主镜变形。锁紧螺丝只需用手拧紧即可。

Bear in mind the collimation pattern may be slightly different depending on the f ratio of your scope.
For more information see below.
望远镜焦比的不同，校准模式会有轻微的不同。详见以下内容。

A note on spider vanes in the view…………

视场中的蜘蛛架：

When collimating the spider vanes, apart from the inistial stage of making sure they are holding the secondary mirror central, are not relevant to the collimation procedure. Ignore them – you should only be looking at the Cheshires cross hairs and making sure that the cross hairs intersect the primary mirror centre spot.

在校准蜘蛛架时，除了在开始时确保其使副镜座居中之外，其它均与校准过程无关。你仅需关注并确保Cheshires的十字丝与主镜的中心点重合。

Fast Slow Telescopes

快慢镜：

You should note that fast scopes of f5 and above are less tolerant of collimation errors and
they also show slightly offset collimation patterns. These are shown below as a guide.

焦比为5甚至更快的望远镜对光轴校准误差更为敏感，且校准模式有轻微的偏移，如下图。






This photograph shows what the actual view should be like at this stage of the process.  
Note the three mirror clips are all visible and are all equally close to the edge of the secondary mirror and
the secondary is showing round and centred to the focuser tube ( the dark area at the edges of the picture)
You may need to move your focuser in or out to achieve a good view but the image should be very similar to
this photograph.

这种图片展示了本阶段应该看到实际视场图。主镜的三个固定爪都可见，且等距位于副镜边缘。
副镜呈圆形且位于调焦筒(图片边界处的黑色区域)中间。你可能需要通过调焦才能获得一个完美的视场。

Slow' telescope when collimated
慢镜校准：



This is an actual photograph taken through a Cheshire and shows a near perfect collimation pattern for a fast (f5)
Newtonian. It is in fact my own Sky-Watcher 200P Note that the centremost circle is made up of the primary mirrors
centre ring and its associated reflection. The cross hairs exactly intersect the centre circle.
Note also the offset typical of a fast Newtonian.

[本段描述的似乎还是关于快镜的，感觉作者是不是写错了！！]

When collimation of the primary has been achieved and the Cheshire pattern is correct tighten down the
locking nuts and recheck. Do not over-tighten the lock nuts. They should be firm but do not require massive
amounts of pressure. I usually feel for them coming into contact with the mirror cell and then add a small amount
of pressure.

当主镜校准完成时，锁紧螺丝并重新检查。锁紧螺丝只需保证其稳定不动而不要过分用力。通常只需锁紧螺丝贴合主镜再增加一点点压力即可。

Replace any protective plates and remove the Cheshire collimator.

移除任何保护板和Cheshire校准器。

When this step is completed and all of the alignment patterns shown in this guide are true then the telescope
is collimated to within the limits of what you can achieve with a Cheshire and you should find the telescope
is perfectly well collimated for use.

当本步骤完成，且所有组件如本向导中描述的那样对齐时，在你使用的Cheshire校准器的精度下，你的望远镜已完成光轴校准。

You may wish to carry out a ‘star test’ to verify this and/or to make any fine fine tuning adjustments.
Star testing is simple enough to carry out and there is a section below which will explain this and show
the most common problems.

你可能还希望进行一次星点测试以确认是否还需进一步微调。星点测试非常简单，下一节将详细展开。

So – get it as good as you can but do not overly worry if there is some small element which isn’t perfect.
My own collimation via a Cheshire is always a little ‘off’ – star testing confirms the scope as being spot on
so bear this in mind.

尽你最大的努力进行校准，但是如果还有些小的偏差也不用担心。我自己的校准也经常会有一些小偏差。

Star Testing Your Telescope

星点测试

When collimation is complete you may wish to carry out a star test which will confirm the collimation or
show small errors which can be fine tuned out.

当校准完成后，你可能希望进行一次星点测试以确认校准精度或进行微调。

To star test you will need a bright star and good seeing conditions. Polaris is the best star to test on
but almost any bright star will do. You will need your telescope to have cooled down to the ambient
temperature and also to be away from obstructions such as houses which may cause air thermals.

星点测试需要一颗亮星和好的视宁度。北极星是很好的选择，其它亮星也可以。望远镜需完全冷却且远离能引起空气扰动的障碍物，例如房子等。

Get the star centred in your view using a low power eyepiece. Now use a very high power eyepiece
( or the highest powered you have available) and defocus VERY slightly. You should see a classic Airey disk
as shown in the pictures below. Ideally the Airey disk will be perfectly formed for both sides of the perfect
focus (Extrafocus and Intrafocus) but in reality most telescopes wont do this perfectly owing to slack within the
focus mechanism or atmospheric turbulence but you should see an Airey disk on at least one side of the perfect
focus position.

首先使用低倍目镜将亮星置于视场中间，然后更换高倍目镜(你能获得的最高倍目镜)并使之轻微失焦。这时你会看到如下图所示的经典艾里斑。
理想情况下，在焦点两侧(焦外和焦内)艾里斑都会完美形成，但是实际情况下，由于调焦机制和大气扰动的影响，多数望远镜很难做到焦内焦外
都形成完美的艾里斑。不管怎么样，你应该在焦点某侧(焦外或焦内)看到艾里斑。

The optimum magnification for star testing is at 25x per inch of aperture to start with and then fine tune at 50x
per inch if seeing permits – you will need a very stable sky to get maximum magnification.

开始星点测试的最佳倍率是每英寸(口径)25X，如果视宁度好的话可增加至50X，为了使用最大倍数你需要一个稳定的夜空。

If you are not seeing an Airey disk this then there are several reasons why. This may be due to faulty
collimation or other conditions which may not be correctable.

一些原因，例如，校准失败或其他一些未考虑到的条件，可能会导致看不到艾里斑。

A list of common conditions and their corrective responses are shown in the tables below.

下表列举一些常见的情况以及对应的现象。

Be aware that in UK skies atmopsheric turbulence will be very often the pattern you will see.
Unfortunately the typical turbulence pattern is very similar to the pattern you will see with a badly
damaged mirror. Unless you have reason to believe the mirror IS damaged then there is no need to panic.

Even a turbulent atmosphere pattern will allow you to see whether the circles are concentric or whether
they are off centred and non-concentric.

完美星点：


Airey disk shows neat concentric circles.  The innermost are dark due to the telescopes central obstruction caused
by the secondary mirror.

艾里斑完美同心。最内层的黑色区域是由于副镜带来的中心遮挡导致的。

校准偏差：


Results such as these suggest the primary mirror is not well aligned. This is simple to correct in the field by
adjusting the primary mirror collimation screws. Small adjustments only are needed.

这样的星点表示主镜没有完全对齐。这种情况只需微调主镜调节螺丝即可。

大气扰动：


The air around the telescope and in its line of sight is being disrupted by rising heat or by higher altitude
turbulence. You cannot star test with this present.

望远镜周围及镜筒所在光柱存在大气扰动，这种情况下不能进行星点测试。

过渡锁紧：



this is the classic ‘heart’ shape indicating the primary mirror has become stressed. Initially check that the
collimation adjusters are not over tight.
If the problem persists you will need to remove the primary mirror cell and make sure the clips holding the mirror
to the cell have not been over tightened.
Another common cause of ‘pinching’ is often over tight tube rings.
这是经典的心形星点，表示主镜承受的压力过大。首先检查主镜调节螺丝是否过度锁紧。如果问题继续出现，可能需要将主镜从镜筒取下以
检查主镜固定爪是否过度锁紧。还有可能是镜筒过紧。

望远镜冷却：

the telescope has not cooled sufficiently to the outside air temperature.
Allow the telescope more time to cool down.
望远镜冷却不充分，花点时间继续冷却。

像散：


Astigmatism can be caused by poor collimation but also by poor quality optics.
Secondary mirrors which are not flat either because of bad collimation or bad polishing are typical causes.
像散可能由校准失败导致，也可能是望远镜光学组件质量太差，例如副镜表面不平。

Zonal Error：


Usually caused by incorrect figuring of the primary mirror.
This cannot be corrected by the user. It indicates faulty optics in the mirrors design or production.
通常是主镜形状不正确导致。这种情况无法校准。表示望远镜的光学组件有缺陷。

Optical surface damaged:


These show typical patterns for mirrors with poor optical surfaces.
This may be caused by roughness of the mirror caused by poor polishing or damage from poor cleaning.
This is not correctable.

这通常表示光学组件表面有问题。可能是低质量的制作工艺或清洁，这种情况无法校准。

未完待续，休息一下，翻译的眼睛疼

建议调下字体颜色，黑底白字看着好累

坐等楼主更新

辛苦啊

纠结者粗调，星点细调，简单高效

辛苦楼主

造福大家，赞！

周末犯懒没更新，今天补上，全文完

新手的福音啊

oca电子光轴· 简单，结了~

辛苦了。好贴收藏！

qiaokeli 发表于 2020-11-18 14:52
辛苦了。好贴收藏！

牛反就是折腾，不过折腾好了确实不错

578721687 发表于 2020-11-17 10:55
新手的福音啊

一起进步

给楼主点赞！

刘明刘明，感觉很有用

学习了，慢慢摸索。

学习了，感谢楼主辛苦翻译。

先留，有时问慢慢看