oc #: 3500A 015 0001 Revision: Rev€¦ · Wiyn Optics Cleaning Procedure 3500-AD-015-0001.Docx...

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Doc #: 3500-AD-015-0001 Revision: Rev

WIYN Optics Cleaning Procedure

Author(s): Patrick Dunlop

Larry Reddell

Victor Moreno

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Wiyn Optics Cleaning Procedure

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Contents

Contents .......................................................................................................................................... 2

Revision History .............................................................................................................................. 3

1. Purpose .................................................................................................................................... 4

2. Applicable To ........................................................................................................................... 4

3. Scope ....................................................................................................................................... 4

4. Definitions ................................................................................................................................ 4

5. Training .................................................................................................................................... 4

6. Safety ....................................................................................................................................... 4

7. Personnel, Equipment and Materials Required ...................................................................... 5

8. Procedure ................................................................................................................................ 7

9. Procedure Review .................................................................................................................. 20

10. Records .............................................................................................................................. 20

11. References ......................................................................................................................... 20

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Revision History

Rev

Date

Sections Affected

Reason for Change

Remarks and/or Change Details

Name

-- 3/12/2014 Original: Patrick Dunlop

Approved by:

SigEng

Name, ME Title

SigEM

Name, EL Maint

SigSci

Name, SciOps

Signature 28 August 2018 Tammie Lavoie, Safety Manager Date

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1. Purpose

This procedure describes the processes for cleaning the mirrors for the WIYN 3.5 meter primary mirror and .7 meter tertiary mirror. The document includes an overview for planning and preparation, mirror cleaning procedure, and coating evaluation.

2. Applicable To

3. Scope

The following tasks are to be planned to assess and clean the mirror coatings of the WIYN telescope. Perform a visual inspection of each component to assess overall condition. Document and make

notes of any anomalies that are observed. The anomalies include but not limited to items such as

water spots, oil spots, insect residue, coating degradation, scratches, and digs.

Measure reflectance and scatter for each mirror at approximately the locations shown in Figure 1 below.

Clean the mirrors.

Re-measure reflectance and scatter for each mirror at approximately the same locations as for the pre-cleaning measurements.

Repeat the visual inspections and assess the overall condition of each component.

4. Definitions

5. Training

6. Safety

1. JHA Form 2. Daily Briefing Form

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7. Personnel, Equipment and Materials Required

7.1 Contact Cleaning Materials:

The supplies needed for cleaning are shown in Table 1 below and are discussed in the following paragraphs. Acetone, Xylene, and Isopropanol are used for cleaning small non-water-soluble contamination spots either before or after other cleaning. These are available from chemical supply providers. For use, they should be transferred to labeled wash bottles. In addition to separate bottles for each solvent, a 50/50 mixture of acetone and Xylene can be prepared and used as well. Lemon Joy dishwashing detergent or a similar mild non-particulate detergent is mixed with water to spot clean water soluble marks. The solution of 2 drops of detergent to 250 ml of water should also be in a wash bottle. Orvus soap is mixed with water to do mirror contact washing. A mixture of 25 ml of Orvus and 2 gallons of distilled water is placed in a 3-gallon compression garden sprayer available from lawn and garden centers. A second 3-gallon compression garden sprayer is used for distilled water for wetting the mirror and final rinsing. Contact washing of the mirror is done with a natural sea sponge that has been conditioned prior to use by soaking it in a 2-10% hydrochloric acid and water solution (HCL/H2O) until all the coral in the sponge has been dissolved. This minimizes damage to the mirror coating during washing. Only the natural sea sponge is to be used. The sponge should be stored in a clean, sealed, damp container.

Technicloth Wipers (TX609) are used with the solvents for spot cleaning. Kimwipe wipers are used to dry the mirror after contact washing.

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*Conditioned: Soaked in a 2%-10% HCl/H2O Solution until coral dissolved

Supplies for Mirror Wash Procedure

Chemicals

Acetone

Xylene

Isopropanol

Brakeclean

Lemon Joy Detergent 2 drops in 250ml water

Cleaning Materials

Orvus Soap 25 ml in bug spray bottle

Sea Sponge Conditioned prior to use*

609 TexWipes

Kaydry

Long Q Tips

Dust Masks

Hair Net

Nitrile Gloves L

XL

Respirator Cartridge

Water Boots

Water Bib

Distilled Water

Large Spray Bottles 1 with soap mix

1 with distilled water

Visqueen Plastic

3M 764 Orange Tape Or cloth type ductape

Electronics

Laptop Computer

Software

USB Stick

Minolta

Table 1: Cleaning Supplies

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8. Procedure

The following procedures assume all necessary materials are available and accessible. The order of the cleaning procedure are as follows, Pre-Cleaning assessment, Cleaning of the TM, Cleaning of the PM.

8.1 Pre-Cleaning Assessment:

The following is performed prior to any mirror cleaning.

1. Orient the telescope to south facing wash position, rolled south to access ID of the mirror cell.

2. Open the Mirror Covers

3. Install the access platform.

4. Determine a detailed procedure to define both personnel safety and minimization of risk to the telescope components. This procedure will be approved by the designated Responsible Engineer before commencement of operations.

5. Nytril Gloves are to be worn during all stages of the cleaning process.

6. Climb onto mirror cell and or platform to gain access to either mirrors for assessing general conditions and performing reflectance measurements.

7. Assess general condition of Primary Mirror (PM) and Tertiary Mirror (TM) coatings. Perform a pre-cleaning inspection of the PM and TM.

8. Take reflectance measurements of the PM and TM. The PM reflectance measurements are taken across the bottom 1/3 of the OD and ID of the mirror. Measurement locations are depicted in the Figure 1.

a. The platform allows for access to the top half of the PM surface and the TM.

Figure 1: Minolta Measurement positions on Primary and Tertiary mirrors

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8.2 Cleaning of the Tertiary Mirror (TM):

The TM will be contact cleaned only. At a minimum, two people are needed to perform this operation. Four people are recommended, though not necessary, to make the operation smoother and more rapid. The process below assumes four people. The entire operation should able to be completed in about 2 hours. The following steps pertain to cleaning the TM. The telescope should be in the South Facing Wash orientation. 1. Assemble all required materials in the proximity of the telescope.

2. Mix 25 ml of the Orvus soap and 2 gallons of water into one of the compression sprayers.

3. Fill the second compression sprayer with distilled water.

4. Perform pre-cleaning reflectance measurements.

5. On the TM OD, apply 3M orange tape so the adhesive side faces the TM and about half of the width of the tape extends past the mirror surface. This means about 1 inch of tape is exposed. Apply the tape completely along the TM OD perimeter.

6. Apply a second strip of tape to the non-adhesive side of the first strip with about 1 inch of the second strip extending beyond the first strip. Apply the tape along the TM OD from about half way up the PM perimeter, down to the mirror bottom, and about halfway up the other side. The result is an adhesive surface about 2 inches wide to which the plastic sheet will be attached. See Figure 2

7. Cut a strip of plastic sheet to the approximate length and apply one edge to the adhesive side of the tape at the TM OD, leaving about ½ inch of adhesive surface uncovered. See Figure 3

8. After the plastic sheet is in place, apply strips of tape to the plastic and the exposed adhesive surface so as to sandwich the plastic between the two layers of tape. See Figure 3

9. Arrange the plastic sheet along the bottom of the cell support/platform surface to form a pool area near the bottom. The intent is to have the water from washing flow to the pool to be removed with a shop vacuum cleaner. See Figure 4

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Figure 2: Tape Layers on TM OD

Figure 3: Sandwich plastic masking between tapes

½”

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Figure 4: Complete mask of TM

10. Move the shop vacuum cleaner onto the azimuth base so that its nozzle can reach the plastic where the water pools up.

11. Position two people on the platform. One person will spray the water and soap solutions and perform the sponge washing and drying.

12. Position one person on the ground to vacuum water from the pool and help provide supplies to the other people.

13. With all personnel in position, pre-rinse the mirror using distilled water from top down.

14. Clean sponge with H2O

15. Spray the rinsed section with the Orvus soap and water solution

16. Clean the mirror from top down by lightly sweeping the sponge in a figure eight motion over the sprayed section. At the same time, continuously spray the soap solution four to six inches above the sponge to create a constant lubricating surface between the sponge and the mirror surface. See Figure 5

17. Final rinse the cleaned section with distilled water to remove soap residue. See Figure 6

18. To dry the surface, make a ball or loose bundle of Kimwipes and use this to rapidly dab dry the surface. See Figure 7. When the Kimwipe stops absorbing water, discard it and use a new Kimwipe. Perform the drying process quickly from the top down until no moisture remains on the mirror surface.

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Note: Remove Tap at area being dried; Tape removal will likely splatter water onto the mirror when removed. Do not touch mirror with gloved hands during the drying process.

Figure 5: Cleaning of the mirror

Figure 6: Rinsing the mirror

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Figure 7: Dabbing the mirror dry

19. Perform a post-cleaning inspection, identifying spots that need to be addressed with spot cleaning.

20. Carefully remove the plastic sheet and tape masking from the TM OD. Dry any water that gets onto the mirror surface. Look for water in the area between the mirror and pool surface and dry anything that is noticed.

21. Remove all equipment and cleaning materials from the telescope.

22. Perform post-cleaning reflectance measurements.

8.3 Cleaning of the Primary Mirror (PM):

The PM will be contact cleaned only. At a minimum, two people are needed to perform this operation. Four people are recommended to make the operation smoother and more rapid. The process below assumes four people. The entire operation should able to be completed in about 3 hours.

1. Assemble all required materials in the proximity of the telescope.

2. Mix 25 ml of the Orvus soap and 2 gallons of water into one of the compression sprayers.

3. Fill the second compression sprayer with distilled water.

4. Perform pre-cleaning reflectance measurements.

5. Position the access platform within the PM Mirror Cell according to Figure 9.

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6. Remove the ODI (One Degree Imager) Port Baffle from the right dec. axis. Carefully unbolt and left without contacting the mirror surface. Exercise Extreme Caution. See Figure 8 below.

Figure 8: ODI Port Baffle

Figure 9: Work Platform in PM Mirror Cell

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7. On the PM ID, apply 3M orange tape so the adhesive side faces the PM OD, and about half of the width of the tape extends past the mirror surface. This means about 1 inch of tape is exposed. Apply the tape along the complete ID of the PM.

8. Apply a second strip of tape to the non-adhesive side of the first strip with about 1 inch of the second strip extending beyond the first strip and completely wrap the ID. The result is an adhesive surface about 2 inches wide to which the plastic sheet will be attached. See Figure 2

9. Cut a strip of plastic sheet to the approximate length and apply one edge to the adhesive side of the tape at the PM ID, leaving about ½ inch of adhesive surface uncovered. Wrap the top half of the PM ID in plastic. See Figure 10

Note: Attach TM Cover, Protect the TM from water spray during PM Cleaning Process.

10. After the plastic sheet is in place, apply strips of tape to the plastic and the exposed adhesive surface so as to sandwich the plastic between the two layers of tape. See Figure 3

11. On the PM OD, apply the tape so the adhesive side faces the PM ID and about half of the width of the tape extends past the mirror surface. Apply the tape along the PM OD completely around the perimeter.

12. Apply a second strip of tape to the non-adhesive side of the first strip with about 1 inch of the second strip extending beyond the first strip. Apply the tape along the PM OD from about half way up the PM perimeter, down to the mirror bottom, and about halfway up the other side. The result is an adhesive surface about 2 inches wide to which the plastic sheet will be attached. See Figure 11

13. Cut a strip of plastic sheet to the approximate length to cover about halfway up one side, down the bottom of the mirror to about halfway up the other side. Apply one edge of the plastic to the adhesive side of the tape at the PM OD, leaving about ½ inch of adhesive surface uncovered. Figure 12

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Figure 10: PM ID Plastic Wrap

Figure 11: PM Tape Mask

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Figure 12: PM Plastic Mask in place

NOTE: The Mirror is cleaned in two different stages. Top half is cleaned first, followed by the bottom half.

14. Move the shop vacuum cleaner onto the azimuth base so that its nozzle can reach the pool.

15. Position two people on the platform. One person will spray the water and soap solutions as directed. The second person will perform the sponge washing and drying.

16. Position one person on the ground to vacuum water from the pool and help provide supplies to the other people.

17. With all personnel in position, pre-rinse the mirror using distilled water from top down.

18. Spray the rinsed section with the Orvus soap and water solution

19. Clean the Top half of the mirror from top down by lightly sweeping the sponge in a figure eight motion over the sprayed section. At the same time, continuously spray the soap solution four to six inches above the sponge to create a constant lubricating surface between the sponge and the mirror surface. See Figure 13

20. Final rinse the cleaned section with distilled water to remove soap residue from the top down as shown in Figure 14.

21. Remove the orange tape from the top half of the mirror.

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22. To dry the surface, make a loose bundle of Kimwipes use this to rapidly dab dry the surface. See Figure 7. When the Kimwipe stops absorbing water, discard it and use a new Kimwipe. Perform the drying process quickly from the top down until no moisture remains on the mirror surface.


24. Remove the access platform from the mirror cell.

25. Repeat steps 17-21 for cleaning of the bottom half of the PM.

Figure 13: Cleaning the PM

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Figure 14: Rinsing the PM

Figure 15: Drying the Bottom half of the PM

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27. Carefully remove the plastic sheet and tape masking from the PM OD/ID. As you dry mirror from top down, dry any water that gets onto the mirror surface. Look for water in the area between the mirror and pool surface and dry anything that is noticed.

28. Remove all equipment and cleaning materials from the telescope.

29. Perform post-cleaning reflectance measurements.

8.4 Spot Cleaning Procedure:

Spot cleaning with solvents is used as a method to clean the mirror surfaces of non-water-soluble contaminates, and can be used during or in-between mirror cleanings. Areas to look for are fingerprints, spots on the surface with a rainbow-like shine to them, indicating oil residue, and contaminates that were not removed during the cleaning procedure. Spot cleaning can be performed either pre- or post-cleaning. It is important that clean Nytril gloves are worn thought the clean process.

The following steps pertain to spot cleaning on any mirror surface using a solvent.

1. Acetone/Xylene 50/50 mix is the usual choice for spot cleaning.

2. Hold the Texwipe against the mirror surface.

3. Saturate the wipe with the solution.

4. Lightly massage the wetted area with a finger over the wipe, being sure not to allow the wipe to scrub the mirror.

5. If the acetone/Xylene mix does not remove the spot, try acetone, or Xylene, or Isopropanol individually.

6. If those efforts are unsuccessful, do no more cleaning with the solvents.

8.5 Snow Cleaning Procedure

Snow Cleaning benefits are only seen if snow cleaning is done regularly. At the least, a weekly snow wash is recommended; however, daily snow wash is ideal. With weekly snow washings, the scheduling should be based around the weather to reduce the impact of condensation events. If a storm is coming or a rise in humidity is projected, the weekly snow wash should be performed prior to the event. The following steps pertain to snow wash cleaning on any mirror. 1. Liquid Draw CO2 bottles are used for snow cleaning. Takes almost an entire bottle to clean the PM,

TM and SM.

2. Assemble the cap and wand.

3. Turn the CO2 on so that a soft fine spray comes out the nozzle.

4. Hold the head 12-24 inches off the surface of the mirror and spray the entire mirror, should only take a minute or two.

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Figure 16: Snow Cleaning the WIYN Primary

9. Procedure Review

10. Records

11. References

KPNO Emergency Manual

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