auto collimator

Operation manualAutocollimatorAKR 300/65/14,7

-------------------------------------------------------------------------------------------------------------------------------------------------MÖLLER-WEDEL OPTICAL GmbH, Rosengarten 10, D-22880 Wedel, GermanyOperation manual AKR 300/65/14.7-------------------------------------------------------------------------------------------------------------------------------------------------

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ContentsPage

1. General 3

2. Unpacking and cleaning 3

3. Preparation for operation 3

4. Initial installation 5

5. Function description of the instrument 6

6. Maintenance 10

7. Trouble shooting 11

8. Spare parts 13

Annex


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1. GENERAL

Autocollimators are used for high precision angle measurements, alignment of optical components or systems, testing of optical quality, radius measurement,measurement of straightness, flatness and rectangularity.

2. UNPACKING AND CLEANING

The autocollimator is a precision angle measurement instrument which interacts with mirrors or prisms.Unpack equipment carefully.No humidity, no shock stress!

Keep clean the optical components such as lenses of the objective and of the eyepiece, and mirrors. Remove dust protection caps only for use of the equipment and attach after use.

No finger prints!

For cleaning glass surfaces from dust best a blower or painting brush with soft and grease-free hairs. If the contamination is of rigid nature breathe to the glass surface to produce a thin liquid coating and wipe off using a piece of soft leather- do not use force!

orUse a mixture of approx. 20 parts ether and one part alcohol and wipe off-but only after having removed dust beforehand.

When realizing damages when unpacking don´t repair yourself otherwise our guarantee will expire. Contact our distributor or our factory.

Important hint for the use in tropic regions

The equipment is not to be used under tropical conditions.Unpacking should be carried out in closed, air conditioned rooms with a relative humidity not exceeding 75%.

3. PREPARATION FOR OPERATION

Standard illuminationInsert the lamp socket with bulb (is supplied separately) into the autocollimation eyepiece.The cable of the lamp socket (illumination 6V) only to be connected to transformer 220VAC/3,5...6VDC or 110VAC/3,5...6VDC.


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Cold light sourceConnect the light fiber with the cold light source.Insert the other end of the fiber into the autocollimation eyepiece.

Remove protection cap from tube.

Insert the autocollimator into the fixtures D65. Clamping or loosening can bedone with the aid of the fixing screws of the fixture.

Switch on the illumination.

Temperature equalization

Even slight temperature differences in glass lead to stress which will reduce by annealing. For accurate measurements it is, therefore, recommended tostore the autocollimator, mirrors and prisms one day beforehand in themeasuring room.

Objective tube f=300/65 Autocollimation eyepiece Illumination


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4. INITIAL INSTALLATION

Ready for operation after unpacking.When used in tropic region, please refer to hints in chapter 1.

First of all, a suitable positioning for the telescope should be chosen. The type of the positioner is determined by the measuring set-up. Unless prepared in anticipation by the user clamp fixtures are recommended.

When using the clamp fixtures take care when tightening the clamping screws: Do not fasten the barrel clamp screws with excessive force to avoid strain being transmitted to the telescope objective. This would lead to deterioration of the image quality.

If the temperature of the telescope is below 15°C, the same phenomena will occur. In this event the telescope should be kept approx. 30 minutes with room temperature till the telescope has adopted the required temperature through and through. The objective should have the same temperature inside and outside.

Those autocollimators that have the special requirement with regard toaccurate alignment of the optical axis to the outside barrel diameter better than30 microns do not allow free interchange of "Objective tube with objective" andautocollimation eyepiece. If the said modules will be disconnected thealignment is deteriorated and no guarantee can be claimed in such a case.

Pre-Adjustment for initial set-up

In normal applications, an autocollimator interacts with a mirror (autocollimation mirror).

The mirror should always to placed as close as possible to the autocollimator for metrological reasons.

The mirror should be positioned nominally at right angle to the optical axes. When viewing through the autocollimator eyepiece both eyepiece reticle and the illuminated collimator reticle should be seen. If the collimator reticle does not appear in the eyepiece either the autocollimator or the mirror are to be tilted accordingly.


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5. FUNCTION DESCRIPTION OF THE INSTRUMENT

Construction feature (shown for straight viewing AKG type)

The autocollimator is essentially a telescope focused at infinity and fitted with means for illuminating an internal target reticle. The illuminated target reticle is situated in the focal plane of the objective and the emergent beam is directed along the axis of the telescope by means of a beam splitter. The reflected beam having passed through the beam splitter is brought to a focus of the eyepiece reticle and both the eyepiece reticle and image of the target reticle are viewed simultaneously through the eyepiece.

What is autocollimation?

The autocollimator projects the image of a reticle in a parallel beam (collimated light) onto the mirror, which reflects the beam back into the autocollimator. This is the autocollimation image. If the mirror is perpendicular to the optical axis, the beam is reflected back into itself.

If the mirror is tilted through the angle λ, the reflected beam falls into the lens at an angle. Depending on the inclination of the reflected beam, the autocollimation image is displaced to a greater or lesser degree.

The displacement of the autocollimation image in x- and y-direction provides a measure of the angular displacement of the mirror.

Autocollimation means parallel light. The measuring result is independent on the distance.


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Normally the autocollimators are set to infinity at visible wavelength λ=546nm. Use of the autocollimator at other wavelength causes a shift of the focal plane due to the changed optical path.

For use the autocollimator at a wavelength which is different from 546 nm it is necessary to adjust the collimator and eyepiece reticle at a distance which is different from the standard distance (Zero setting).

In the annex you find the calculated chromatic focal shift for the described instrument.

Quality of mirrors

For autocollimation measurements only mirrors of high grade flatness are suitable. Mirrors dia. 63 mm should have a flatness of 0.05 microns.The measuring accuracy will deteriorate when using mirrors of minor flatness tolerances.

General hints

Turbulence of air between Autocollimator and mirror lead to spurious deflection of the light bundle thus falsifying the measuring results.

Range between Autocollimator and mirror

The angle display and the measuring accuracy are independent of the range.With increasing range between Autocollimator and mirror only the measuring range will decrease.

The standard version of the Autocollimators with focal length 1100 mm and tube dia. 105 mm the max. range between Autocollimator and mirror is 20 m.

Reticles

Autocollimators include two reticles. These are the eyepiece reticle and the collimator reticle. The eyepiece reticle is in the most cases a double crossline or an angular graduated scale nd can be observed when viewing through the eyepiece with the illumination switched off and the dust protection cover removed.The collimator reticle (single crossline) appears in the same plane as the eyepiece reticle but can only be observed with the illumination switched on and with the aid of a mirror being placed in front of the Autocollimator rectangular to the optical axis.


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Angle reading

Depending on the version of the Autocollimator the angle of the mirror tilt can be read off as follows:

Autocollimator with angle reticle

5 Collimator reticle 2,5

2,5 5 Eyepiece reticle

The Autocollimator should be adjusted in such a manner that the collimator reticle indicates zero degrees when the mirror is in its datum position. The tilt of the mirror will cause deflection of the collimator reticle (also called autocollimation image) which can be read off the scale.

See sketch: vertically 4’ horizontally 2,5’

The eyepiece reticle S422 for autocollimator AK 300/65/.. gives correct readings in autocollimators that interact with a mirror. If the autocollimator is used as a telescope the angle value taken from the scale must be multiplied by 2.

Autocollimators with double micrometer

Using an autocollimation eyepiece with double micrometer the displacementcan be read out very precisely.

One division of micrometer graduation corresponds to 5µm. Depending on the focal length of the autocollimators it corresponds to the following angle shown in table 1.

focal length in mm 200 300 500 1100corresponding angle in arcsec 2.5 1.75 1 0.5


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By turning the micrometer screws on the x- and y-axis, the eyepiece reticle (double-cross-lines) is moved out of reference position so that the double lines lie symmetrical to the single lines. The distance moved is equal to the travel of the cross-lines and can be read off at the micrometers.

Between displacement x resp. y read off at the micrometers, and the angular change in mirror position, there is the following relationship:

α = Y/2f

α = mirror inclination (radian) Y = distance of autocollimation image from its zero position f = focal length of autocollimator lens

x x

y y

For Autocollimation Telescopes of focal length f = 1100 mm and micrometers with the smallest graduation interval of 0.005 mm we obtain:

1 graduation interval at micrometer=

0.5“ mirror inclination

Autocollimators with programmable digital gauges

These instruments also have the single- and double-cross-lined reticules with mechanical adjustment of eyepiece reticle positions. They are also equippedwith micrometer screws with digital measuring gauges that are programmable.The reading can be directly in angular units, if using as angular unit arcsec, thedisplayed value must be multiplied by 10. As the resolution of the digitalgauges is 1 µm, the angular resolution is 5 times better than with normalmechanical micrometer.


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6. MAINTENANCE

If the instrument is treated carefully as is usual with optical instruments the autocollimator will not need maintenance.Outer surfaces of objective and eyepiece may be contaminated in the course of the time. If so, clean as follows:

First remove particles from the dust from the surfaces using a blower. Wipe over with a dry piece of fine linen. If this fails, but only then, the surface should be cleaned with a mixture of approx. 8 parts by volume of ether and one part of alcohol.Handle with care! The mixture is inflammable.

The outer surface of the objective tube does not need maintenance.


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7. TROUBLE SHOOTING

Trouble RemedyAutocollimation image ofpoor contrast

a) The objective has fog formation or is contaminated. Clean objective.b) Eye lens of the eyepiece contaminated. Clean the same.c) The autocollimator optic too cold. Wait for approx. 30 minutes till the optical components have adapted the determined temperature through and through.d) Autocollimator mirror has not the required planeness. Use better mirror (planeness approx. λ/5 or better over diameter 60 mm)

Autocollimation image andeyepiece reticle do notappear equally well defined

a) Autocollimation mirror not sufficient plane. Replace.b) Objective not positioned correctly relative to the reticle. refer to item 5 for setting the objective.c) Autocollimation eyepiece disadjusted. Return to supplier for repair.

Autocollimation imageappears astigmatic

The means, the autocollimation eyepiece appears sharponly partly in the field of view.a) Autocollimation mirror not sufficient plane. Replace.b) Autocollimator optic too cold. Wait for approx. 30 minutes till there is same temperature in the instrument through and through.c) Autocollimator is clamped with excessive force near the objective thus introducing stress into the glass.Attach barrel not to strongly.

Lines of the reticles are notpositioned parallel to eachother

The reticles do not have proper image erection and haveto be rotated. Send instrument to supplier.

Reticle image appears withpoor resolution

Objective positioned out of focus. Set objective.Note:The following procedure may deteriorate thecoincidence between the tube axis and the optical axis.The reticle center with regard to the tube axis(mechanical) will remain.This repair should not be made with instruments wherethe coincidence between optical axis is accuratelyspecified. Repairs under guarantee are excluded in thisconnection if this adjustment is made by the customerhimself.


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1 - Ring (4,7: blackened zone)2 - Objective3 - Screws M2x35 - Tube6 - Mount8 - Clamp ring9 - Cover ring 6/300 with thread10 - Dust protection cap

Remove dust protection cap and cover ring No. 9,loosen (do not remove) three screws No. 3, rotate mountNo. 6 (Two engagement crews with simple self-madetool) till proper focusing is achieved.Re-assemble in reversed manner.

6) No lens displacementwhen rotating diopter Ringof the eyepiece

Unscrew the eyecup and tighten the three small screws(metrical thread M2x2-DIN 914) that are exposed afterremoving the eyecup. Attach eyecup.

Inspection points Twice a year the infinity setting should be tested using aplane mirror with flatness λ/5 at diameter 2 inches. Incase of misadjustment the autocollimation image won´tappear clearly defined.Further inspections normally not applicable.


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8. SPARE PARTS AKR 300/65/14,7

8.1. Modulare replacement units

Ident-No. Description Quantity211 301 Objective tube with objective 1

f=300 mm, D65219 120 Autocollimation eyepiece 1

AKR-Ok. 14,7 includingcollimator- and eyepiece reticleeyepiece f=14,7 mmillumination 6V/5W

217 015 Eyepiece f=14,7 mm 1

8.2. Replacement parts

Ident-No. Description Quantity123 103 03 Bulb 6V/5W 1217 306 Adapter with condensor and 1

green filter217 307 Bulb mount with cable 1217 015 05 Eyepiece cover ring 1

(M28x0,75)211 222 02 Objective cover 1135 101 02 Eyepiece cover 1122 104 74 Fuses for transformer 220V 1

6V/5W


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ANNEX 1

Table of chromatic focal shift for autocollimators with achromatic objectives(paraxial)

λ innm

Line Lamp Back focal length difference (Focal shift in microns)

Focal length in mm 50 90 140 200 300 500 1100365 i Hg +0.517 +0.932 +1.470 +2.119 +3.189 +5.484 +10.439405 h Hg +0.206 +0.372 +0.586 +0.846 +1.276 +2.218 +4.282436 g Hg +0.095 +0.173 +0.272 +0.392 +0.595 +1.049 +1.983480 F´ Cd +0.024 +0.043 +0.068 +0.098 +0.151 +0.277 +0.501546 e Hg +0.000 +0.000 +0.000 +0.000 +0.000 +0.000 +0.000644 C´ Cd +0.028 +0.048 +0.077 +0.110 +0.161 0.252 +0.700707 r He +0.059 +0102 +0.163 +0.234 +0.344 +0.550 +1.497852 s Cs +0.149 +0.298 +0.417 +0.599 +0.888 +1.452 +3.8031014 t Hg +0.257 +0.535 +0.747 +1.076 +1.599 +2.639 +6.8001064 +2.8801540 +7.301

auto collimator

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