2100‐AD‐015‐0005 Mayall 4 Meter Primary Mirror Removal ... · 2100‐AD‐015‐0005 Mayall 4...

2100‐AD‐015‐0005

Mayall4MeterPrimaryMirrorRemoval/InstallationProcedureJune11,2014

Patrick Dunlop

This procedure describes the processes for removing the Mayall 4 meter primary mirror. The document

includes an overview for planning and preparation, optics removal procedure, and reinstallation.

2100‐AD‐015‐0005 Revision: A Mayall 4 Meter Primary Mirror Removal/Installation Procedure

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Contents

Overview: ...................................................................................................................................................... 3

Dome Lockout Procedure ............................................................................................................................. 3

Optics Removal Materials and Supplies: ....................................................................................................... 4

Removal Procedure: ...................................................................................................................................... 5

Pre‐Removal Assessment: ......................................................................................................................... 5

Position all handling equipment to designated areas on main floor ........................................................ 6

5 ton dome crane can be used for Steps 1‐2 ......................................................................................... 6

Primary Mirror Removal Procedure: ....................................................................................................... 10

Day 1: .................................................................................................................................................. 10

Day 2: Electronics Maintenance ......................................................................................................... 14

Day 3: Electronics Maintenance ......................................................................................................... 14

Day 4: .................................................................................................................................................. 14

Day 5: .................................................................................................................................................. 19

Day 6: Remove Primary Mirror Cell .................................................................................................... 22

Day 7: Lower Primary Mirror to Ground Floor .................................................................................... 33

Day 8: Stripping, Cleaning of Primary Mirror, ..................................................................................... 34

Day 9: Aluminization of Primary Mirror .............................................................................................. 34

Day 10: Aluminization of Primary Mirror (Contingency Time) ........................................................... 34

Day 11: Re‐Installation of 4 Meter Primary Mirror Optics: ................................................................. 34

Day 12 ................................................................................................................................................. 34

Day 13 ................................................................................................................................................. 35

Day 14: Install electronics racks (Electronic Maintenance) ................................................................ 35

Day 15: Install electronics racks (Electronic Maintenance) ................................................................ 35

Day 16: ................................................................................................................................................ 35

Day 17: ................................................................................................................................................ 36

Telescope Checkout Procedure: ............................................................................................................. 36


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Revision Table ............................................................................................................................................. 37

Overview:The following tasks are to take place prior to and during the optics removal process of the 4 Meter

telescope.

Perform a visual inspection of each component to assess overall condition. Document any

anomalies that are observed.

Stage all necessary gear/tools to be used during the removal/installation process (Table 1).

Hold a toolbox meeting each day prior to work start. During this meeting assign the daily

manager, define the goals for the day, and reinforce that above all else the work is to be done in

a safe manner.

Perform the Dome Lockout Procedure after the completion of work for the day.

DomeLockoutProcedure

1. Lockout visitor access nightly to allow the facility to remain open for day tours.

1.1. Select locations may be closed to the public depending on project.

2. Lockout‐Tagout dome rotation and crane operations.

2.1. If loads are left suspended on any crane in the dome, immobilize dome rotation with come‐a‐

longs.

3. Check for people in building.

4. Shut off lights.

5. Padlock exit doors.


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OpticsRemovalMaterialsandSupplies:

The supplies needed for removing the 4 Meter Mirror are shown in Table 1 below and are discussed in the following paragraphs. The tools listed in Table 1 must be located and stored on the main floor in advance of the shutdown.

SuppliesforOpticsRemoval2EAthreadedguidepinsforPrimaryMirrorcell2EAthreadedguidepinsforCoudé#3 2EArailshatchtofloor 4EAliftinganglesforcage 4EAjacksandbracebracketsforcage 4EA¾”eyeboltsforshell Floorplates(2x4)forChamberBottom

2EAfloorplatesforjacksofcoudécart 1. 8x8x12blocksforlowershell(6x6willnotwork)

4EAthreadedrodsforloweringCoudé#3 3EAlinearballbearingsforChamberBottomjacks RubberpadsforPrimaryMirrorjacks CoversforO‐ringsonChamberBottom

WashstandsforPrimaryMirror Hydra‐Set

Tools

Electricimpactwrench’sandkeys(1/2”x4") Airimpactwrench,hose,socketsandextensions LargeAllenwrenches ScrewDrivers PipeWrenchandOpenEndWrenches LargeAdjustableWrenches ⅜”,½”,¾”,and1"socketsandextensions Large Torque Wrench

Digital Level

TorqueMultiplierCoffeepot,cups,sugar,cream,onutilityfloorSafety Equipment

Hard Hats

Eye Protection

Ear Protection

Gloves

Safety Shoes

Fall Protection

Table 1. Supplies and Materials


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RemovalProcedure:The following procedures assume all necessary materials are available and accessible. The order of the

Primary Mirror Removal/Installation Procedure is as follows:

1. Pre‐Removal assessment

2. Removal of the Primary Mirror Cell

3. Removal of the Primary Mirror

4. Reinstallation

Pre‐RemovalAssessment:

The following tasks are performed prior to beginning removal of the Primary Mirror (PM):

1. Check out 5 ton and 50 ton dome cranes.

1.1. Speed Control

1.2. Brakes

2. Clean cranes and drip pans of excess grease, dirt and debris.

3. Clean upper shutter drive gear box drip pans of excess grease, dirt and debris.

4. Damp mop the crane and upper dome platform area.

5. Check and lube primary mirror elevator platform.

5.1. Ball Screw Nuts

5.2. Drive Plate to Mast Spherical Bearing.

6. Check and lube out‐haul crane on 3rd floor.

7. Damp mop all non‐carpeted floor areas.

7.1. Console and Main Floor levels.

8. Check operation of Hydra‐Set.

NOTE: The critical role of the Hydra‐Set is that of a scale. During the 2014 shutdown the lifting functionality of the Hydra‐Set did not work but the 50 ton crane moves slowly enough to make lifting with the Hydra‐Set unnecessary.


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Positionallhandlingequipmenttodesignatedareasonmainfloor

5tondomecranecanbeusedforSteps1‐2

1. Remove north platform stairs and store in north‐west

corner of console floor.

2. Remove center hatch cover.

50 ton dome crane must be used for Steps 3‐4

3. Remove both outer hatch covers.

4. Lift Chamber Bottom and blue wooden support frames

(2 EA) to east main floor. Orient Chamber Bottom with control side northward.

5 ton dome crane may be used for Steps 5‐9

5. Lift Wooden Triangular Frame (Figure 1) and store on north East Console Floor (Seen under the

mirror cover in Figure 2).

6. Lift orange Primary Mirror Handling Fixture (Figure 2) and store in the center of the wooden

triangular frame.

7. Lift Primary Mirror Wooden Cover and position on top of Wooden Triangular Frame (Figure 2).

Figure 2. Primary Mirror Wooden Cover and Orange Primary Mirror Handling Fixture

Figure 1. Wooden Triangular Primary Mirror Support Frame


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8. Lift Triangular Steel Mirror Support Frame (Figure 3) located on cage cart, 2nd floor above

aluminizing area) and store on East Console Floor.

9. Lift Orange Cassegrain Cage Cart (Figure 4. Orange Cassegrain Cage Cart) and store on west main

floor

50 Ton dome crane must be used for 10 – 11

10. Reinstall hatch covers and position Cassegrain cage cart on hatch rails and remove the south guard

rail.

11. Position Newfirm Cage Bottom in the NE corner of Main floor.

12. Move Circulating Fan to Coudé room.

12.1. Unbolt fan from floor.

12.2. Lift with jib crane to install wheels.

12.3. Roll into Large Coudé Room.

NOTE: Although it doesn’t look like it, the fan will fit between telescope base frame and open Coudé Room door.

13. Remove covers from shell.

14. Remove bolts from north, west, and south scab plates.

14.1. Move Telescope North and South to access bolts on lower shell.

14.2. West scab plate bolts must be removed while telescope is movable.

Figure 3. Triangular Steel Mirror Support Frame

Figure 4. Orange Cassegrain Cage Cart


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15. Remove wings and hand rails from Cassegrain ramp. Remove rails hitting them from underneath

with a hammer. Store wings and hand rails on main floor on north wall of dome.

16. Install safety board angle iron to horseshoe using clamps.

17. Install fall protection.

17.1. Install 2 x 20 ft lifting straps from each of the four corners of the Serrurier truss (Figure 5).

17.2. Install 3 x 20 ft safety retractors inside the cage to the mirror cell (Figure 6), for

instrumentation and electronics removal.

17.3. Install 6 x 20 ft safety retractors to the straps hanging from the telescope truss.

NOTE: When not in use, all retractors should be secured to the net guide wires for easy

Figure 5. Straps for Fall Protection Tie‐off

Figure 6. Safety Retractors Inside Cage


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access while the mirror elevator is down.

18. Remove Cassegrain Instrument (Follow instructions for instrument removal in Instrumentation

documentation).


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PrimaryMirrorRemovalProcedure:

Day1:

At a minimum, 6 people are needed to perform this operation, but 8‐10 people are recommended to make the operation smoother and more rapid. The process below assumes 8‐10 people. The entire operation should take about 1 week.

1. Position the telescope to the south east annex.

2. Remove the mask from the F8 mirror.

3. Flip the secondary to F8.

4. Move RA to about 3 hours East so last set of scab bolts can be removed.

5. Position RA to Zenith.

6. Position telescope to Zenith and level telescope using rotator surface and digital level.

6.1. Partially open Primary and Secondary mirror covers for center baffle removal clearance.

7. Attach Dec stay bar (4 people – 1 in basket, 2 on bottom end of Dec stay bar, 1 running crane).

7.1. Take Dec stay bar up in man‐basket; connect to center section first.

7.2. Connect other end of stay bar to horseshoe.

Figure 7: Dec Stay Bar in position


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8. Install R.A. stay bar.

9. Turn off telescope drives, nitrogen and hydraulics.

NOTE: Lock Out drives and Oil Pumps.

10. Remove cage bottom as described in 2100‐AD‐015‐0013 ‐ 4 Meter Cass Cage Bottom Removal

Procedure – store on console floor by SE Annex (Performed by Instrumentation Group).

11. Remove the Cassegrain instrument (Performed by Instrumentation Group).

NOTE: Remove bulkhead panel with He lines. Drape lines against west wall and secure with rope to keep from stressing connections.

12. Install white alignment scope adapter and K&E Alignment Scope to the guider / rotator (Performed

by Instrumentation Group).

Figure 8. Cage Bottom on Cart in Storage Location

Figure 9. K&E Alignment Scope Installed on Rotator


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13. Check alignment of f8 and record below:

NOTE: Telescope power must be turned ON to actuate rotator X: ________ Y: ________

14. Remove alignment scope, fixture, and adapter (Performed by Instrumentation Group).

15. Remove guider / rotator with cart. Stow in Coudé room (Performed by Instrumentation Group).

NOTE: Refer to Guider Rotator Removal Procedure 2100‐AD‐015‐0027

16. From Control Console in Control Room, partially open primary mirror cover (Figure 10) to allow

Coudé Stack to clear mirror cover.

Figure 10: Mirror Covers Partially Open


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17. Loosen the arm on the east limit switch so the ramp can pass by without actuating it (Figure 11).

18. Move the ramp all the way east; tie it off to telescope tube so it won’t fall if drivetrain fails.

Day 1 Complete – Handover to Electronics Maintenance for Electronics Removal.

Figure 11. Cassegrain Ramp Limit Switch Bypass


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Day2:ElectronicsMaintenance

1. Connect jumpers for E‐stop, cranes, dome, and telescope.

2. Shut off all power to Cassegrain cage.

3. Shut off two clean power breakers on mezzanine behind south journal – this disconnects 110 VAC

and 220 VAC clean power.

4. Disconnect cables, air, vacuum, Nitrogen and Helium lines from telescope to cage.

5. Remove racks and cables.

Day 2 Complete

Day3:ElectronicsMaintenance

1. Remove racks and cables (continued).

Day 3 Complete

Day4:

1. Remove cage mounting bolts (75 each).

NOTE: Three people needed for this operation ‐ two to hook into internal safety retractors and go up on mirror elevator to remove bolts, one to operate counterweights from control console. NOTE: The third safety retractor should be taken up to avoid damaging it or stretching it beyond its limit as the mirror elevator rises.

2. Raise the mirror elevator with personnel on board.

3. Move transverse Dec counterweights to East / West positions.

3.1. Move transverse counter weights SOUTH to give access to bolts that could not be reached

when the weights are opposite each other in their East / West position. There are red lines in

the cage that indicate to where the weights must be moved.

4. Remove cage mounting bolts on east and west that are now accessible. There are 20 bolts that lie

between the red lines. Stow counter weights back in their east‐west positions.

5. Disconnect J32 and install jumper. This allows for Dome power.

6. Lower the mirror elevator.

NOTE: Once down, all personnel should hook their safety retractors to the net guide wires.

7. Cut all power to the cage. Verify it has been cut off before proceeding.

8. Refer to EM documentation for the removal of the remainder of the cables at this point.


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9. Move orange cage cart (which should be sitting on hatch rails) to primary mirror elevator and

position it as far SOUTH as possible.

10. Raise the mirror elevator enough to install rail stops on the north end of the rails using a 9/16”

wrench.

11. Continue raising mirror elevator into position under Cassegrain cage so the jacks are flush with the

cage support pads.

NOTE: Six people are required for Cass Cage removal: 2 inside, 4 outside (one at each jack).

NOTE: Connect to 2 of the retractors inside the cage. The third internal retractor may have to be taken up to avoid it being damaged or stretched beyond its limits as the mirror elevator rises. Connect to 4 of the retractors hanging from the telescope truss.

NOTE: The cart will have to be moved north once the north end of the cart has cleared the horseshoe.

12. On the Orange Cassegrain Cage Cart, set the jack height to 20 inches as shown in Figure 13.

13. Move the mirror elevator up so the jack pads nearly contact the Cassegrain cage.

Figure 12. Rail Stops

Figure 13. Nominal Jack Height Setting


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14. Determine the first two pads that will contact the cage and tighten them up against the cage.

15. Tighten the other two jacks against the cage.

16. Ensure all four jacks on cart are tight to the cage bottom and that the safety clevises are installed

before removing the remainder of the upper cage bolts (Figure 14).

17. Remove the remaining 55 upper cage bolts.

NOTE: Double check that all bolts are removed before lowering elevator to remove cage.

18. Lower mirror elevator to remove cage.

NOTE: EM must be present to push cabling through cage as it descends and to tie it off

NOTE: Before lowering mirror elevator all the way down, remove the rail stops (9/16” wrench).

19. Move cage and cart north onto the hatch.

20. Install four Lifting Eye L‐Brackets to the cage (Figure 15). Bolts go in from below with a split lock

washer under their heads. Lift the cage and cage cart using 1 inch shackles, the 4‐way strap, and the

50 ton crane (Figure 16). Stop when all weight is taken by the hoist and retighten the jacks against

Figure 14. Cassegrain Cart Cage Jack


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the Cassegrain cage.

NOTE: When using the crane, the telescope power key switch in the control room must be ON to rotate the dome.

21. Store cage and cart on west main floor (Figure 16). Place 4 x 8 wood blocks on the floor directly

under each jack (Figure 17).

Figure 15. Lifting Eye L‐Bracket Bolted to Cassegrain Cage

Figure 16. Cassegrain Cage and Cage Cart Storage Location on West Main Floor Figure 17. Wood Blocks Under Jacks


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22. Install Shell Jacks inside the cage above the Cass cage cart jacks.

23. Remove mirror dial indicators (Refer to EM documentation)

24. Position chamber bottom with triangular steel frame in place on hatch rails using 50 ton crane

(Figure 19). Ensure the chamber bottom is oriented with the power cable away from the telescope.

Ensure the triangular frame is oriented correctly (“N” indication pointing North).

NOTE: Remember to install the linear bearings in the bearing pockets before setting the frame on the chamber bottom.

25. Finger‐tighten the bolts securing the triangle frame to the support pads.

26. Plug in the chamber bottom drive power cable on the far north side of the dome.

27. Drive the chamber bottom onto the mirror elevator.

Day 4 Complete

Figure 18. Shell Jack Installed in Cage

Figure 19. Coating Chamber Bottom with Triangular Steel Frame Positioned on Hatch


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Day5:

1. Raise the mirror elevator enough to install the rail stops.

2. Install rail stops on mirror elevator rails and tighten using a 9/16” wrench.

3. Continue to raise mirror elevator so it nearly contacts shell.

NOTE: Six people (1 per corner and 2 inside cage) are required to remove lower shell. Each person is to connect to a retractor hanging from the straps on the telescope truss.

4. Center the triangle frame on the opening in the bottom of the shell.

5. Center the pads in their x‐y travel visually.

6. Bring Chamber Bottom jacks up to contact shell.

7. Remove north and south scab plate bolts (east and west scab plate bolts have already been

removed).

8. Remove shell (Figure 20).

8.1. Mark Shell position on chamber bottom for reinstallation reference.

9. Lower mirror elevator and remove rail stops (9/16” wrench) when close to the ground.

10. Drive Chamber Bottom with shell onto hatch.

Figure 20. Shell Being Lowered from Telescope


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11. Install lifting eyes (Figure 21) into shell mounting bolt holes (Figure 22).

12. Lift lower shell with 50 ton crane and store on top of 8” x 8” blocks on top of cage. Ensure wood is

positioned so shell load is transferred directly to the Cassegrain cage jacks.

13. Remove black shield (located inside center baffle) from rotator clamps.

14. Position center baffle cart (Figure 24) on elevator under center baffle.

15. Remove center baffle and store SW of elevator (Figure 25); tie in place with rope.

Figure 21. Lifting Eyes

Figure 22. Installing Lifting Eyes Onto Shell

Figure 23. 8x8 Between Shell and Cage

Figure 24. Center Baffle Cart


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15.1. Shim as necessary to level the center baffle to the cart and use guide pins to locate holes.

16. Remove sheet aluminum fan covers.

17. Remove galvanized ducting covers on North, South, East, West mirror cell mounts.

18. Position chamber bottom and triangular steel frame on PM elevator under telescope (Figure 26).

NOTE: Using chamber bottom jacks to level and mirror elevator for travel; ensure all three jacks are in good contact with Mirror Cell.

Day 5 Complete

Figure 25. Center Baffle on Cart in Storage Location

Figure 26:PM cart triangular steel frame in position


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Day6:RemovePrimaryMirrorCell

1. Drive the Chamber Bottom, with the triangle, on to the elevator.

2. Raise the elevator enough to install the rail stops.

3. Install rail stops on rails on elevator and tighten.

NOTE: 7 people are needed for the mirror cell removal ‐ 5 on the outside of the cart, and 2 on the scaffold in the horseshoe. Connect to 5 of the retractors hanging from the telescope truss.

4. Once up to the horseshoe, use the cart as a platform to stand on and loosen, but don't remove, the

7 bolts on the south bracket (Figure 27).

5. Move the elevator up so the Chamber Bottom is above the horseshoe.

6. Break loose, but don't remove, the 7 bolts on the east bracket.

7. Break loose, but don't remove, the 7 bolts on the west bracket.

8. Drive the Chamber Bottom north.

9. Use the Chamber Bottom as a platform to stand on and break loose, but don't remove, the 7 bolts

on the north bracket.

Figure 27. 7 Bolts to be Removed x 4 Places


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10. Install the guide pins on the east and the west sides (Figure 28).

11. Install the 2 scaffolding boards between the elevator and the horseshoe to enable access to the

bolts on the north side once the Chamber Bottom is in place under the cell.

NOTE: Two people should connect to lanyards attached to the cross bar that is supporting the scaffolding.

12. Bring the elevator up, drive the Chamber Bottom to position it under the cell making sure the

triangle is close to level.

12.1. Use a tape measure to measure vertical distances between the cell and the triangle.

12.2. Make vertical position adjustments to the pads by using the hand paddle buttons to move the

E/W pads together and the N pad by itself.

13. Raise the mirror elevator to bring it up so the Chamber Bottom is flush under the cell.

14. Remove the 4 southern‐most cell ventilation hoses (2 of the 3 on each side).

15. Remove the 28 bolts

NOTE: 28 bolts (1 1/4‐7) at 4 interface locations

Figure 28. Guide Pin


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16. Use the Chamber Bottom jacks for initial cell lowering.

17. Once the cell has been deemed separated, use the elevator to lower the cell.

NOTE: The scaffolding will have to be removed once the cell is deemed separated.

NOTE: The cell will have to be rolled south to avoid the edge of the Chamber Bottom hitting the

horseshoe.

NOTE: The cell will have to be clear of the guide pins before moving the Chamber Bottom south.

18. Lower the mirror elevator almost all the way down.

19. Remove the rail stops.

20. Lower the elevator all the way.

21. Once down, all personnel should hook their safety retractors to the net guide wires.

22. Drive the coating chamber bottom (which is now holding the cell and the primary mirror) over

center hatch.

23. Inspect the mirror and its supports for any damage.

24. Remove the 4 caps off the top of the seismic plates (Figure 30).

24.1. Remove the nuts from the top and bottom of the pin

24.2. Unscrew the pin

Figure 29. Lowering Primary Mirror Cell


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24.3. Remove the inner spring

25. Measure and record mirror location relative to Seismic plate columns at the thinnest location:

North: ______

South: ______

East: ______

West: ______

25.1. Fabricate corresponding shims of HDPE or suitable material for 2 adjacent sides. These will be

used to center the mirror during installation.

26. Remove the 8 exterior mirror thermocouples (orange wire) and the 2 exterior RTDs (white wire)

27. Climb on the Chamber Bottom and underneath the cell to get into center hole.

28. Remove the 8 interior mirror thermocouples (orange wire) and the 1 interior RTD (white wire)

29. Remove the 24 edge supports from mirror.

Figure 30. Seismic Retainer and Two Edge Supports


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29.1. Four stripper bolts (shoulder bolts) connect each H‐bracket to the pads epoxied onto the

mirror for a total of 24 (Figure 31).

29.2. Lean each edge support slowly away from the mirror (Figure 32).

29.3. Record the locations of damaged edge supports for later repair.

Figure 31. Four Stripper (or Shoulder) Bolts at Each H‐Bracket

Figure 32. Edge Supports Leaned Gently Away from Mirror


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30. Screw the lateral pads on the Seismic clips in to prevent the mirror from shifting during lifting

(Figure 33).

31. Attach the Hydra‐Set to the 50 ton crane hook rigged as shown in Figure 34.

Figure 33. Lateral Pads Holding Mirror in Position for Lifting

Figure 34. Hydra‐Set and Accompanying Rigging


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32. Attach the mirror lifting fixture, via 3 straps, and the mirror cover, via 4 straps, to the Hydra‐Set

(Figure 35).

33. Lower the mirror lifting fixture and mirror cover over the mirror.

NOTE: PM cover rests on PM face, and there is enough room for the edges of the cover to clear the metrology ball holders that are epoxied to the edge of the mirror – this was verified in 2014.

34. Climb on top of the cover (3 people required).

35. Remove the 3 locking bolts from the arms on the lifting fixture.

NOTE: Do not remove the Pivot Bolts; the Pivot Bolts are labelled

36. Lower the lifting fixture through the center hole of the mirror.

36.1. Make sure the fixture is centered; adjust the crane and dome as necessary.

36.2. Measure with a tape measure the distance from the lifting fixture center post to the mirror.

37. Once the arms have cleared the bottom of the mirror pivot them so the pads are under the mirror

(Figure 36).

Figure 35. Hydra‐Set and Mirror Cover Being Lowered to Mirror


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37.1. One person must climb under the mirror to rotate the arms, one at a time.

37.2. For each arm, lift the rods until the arms are in place.

37.3. Put the locking bolts back in the arms and snug down.

37.4. Snug down the pivot bolts.

37.5. Lower the rods and thread them into the arms making sure to tighten until the green marks

on the rods nuts and the top of the fixture line up.

37.6.

38. Raise the lifting fixture until it just makes contact with the mirror. Measure and adjust centering

again before lifting.

39. Use the Hydra‐Set to lift the mirror (or use the crane in slow speed) until the Hydra‐Set reads 31.5

thousand pounds – this is the weight of the mirror, the mirror lifting fixture, the mirror cover, and

Figure 36. Mirror Lifting Fixture


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rigging (Figure 37).

40. The mirror will start to lift off at this point.

41. Check the 3 load cells to make sure the mirror is lifting off evenly.

42. Adjust the dome and crane as necessary to center the lifting.

43. Lift the mirror out of the cell.

44. Store the mirror on the east console floor on primary mirror wooden triangle fixture (Figure 1) and

8” x 8” beams.

Figure 37. Hydra‐Set at 31.5 Kips ‐ Mirror, Lifting Fixture, Mirror Cover, and Rigging

Figure 38: Lifting PM from PM Cell


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45. Tie a rope around the top of the edge supports on the mirror cell to hold them in.

46. Drive the Chamber Bottom with the mirror cell back on to the elevator.

47. Seven people are needed for the mirror cell installation back on telescope.

47.1. Five on the outside of the Chamber Bottom, and 2 on the scaffold in the horseshoe.

47.2. Hook up to 5 of the retractors hanging from the telescope truss.

48. Raise the mirror elevator enough to install the rail stops.

49. Install rail stops on elevator rails and tighten.

50. Raise the elevator until the cell is flush with the telescope.

NOTE: The cell will have to be rolled north once the Chamber Bottom has cleared the horseshoe.

51. Drive the Chamber Bottom so the pins line up with the brackets.

52. Install the 2 scaffolding boards between the elevator and the horseshoe.

52.1. Two people should hook up to lanyards attached to the cross bar that is supporting the

scaffolding

53. Reattach the cell with 3 bolts at each bracket

54. Lower the chamber bottom

NOTE: The scaffolding will have to be removed once the chamber is separated from the cell

NOTE: The Chamber Bottom will have to be rolled south to avoid the edge hitting the horseshoe

55. Lower the elevator almost all the way down

56. Remove the rail stops

57. Lower the elevator all the way

58. Once down, all personnel should hook their safety retractors to the net guide wires

59. Drive the Chamber Bottom onto the hatch

60. Use 3 of the 4 way lifting straps and the 50 ton crane to move the triangle off the mirror chamber

bottom

NOTE: Make sure to loosen the bolts securing the triangle to the support pads

61. Store the triangle on the C floor

62. Use the 4 way strap and the 50 ton crane to move the chamber onto its holding rails east of the

hatch

62.1. Rotate the Chamber Bottom 180 degrees before setting it down

63. Place the 6 floor rail covers on top of the rails


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63.1. 2 sections on the lift, 2 on the main floor, 2 on the hatch

64. Install all the railings around the hatch

65. Remove the hatch doors

65.1. Attach the 4 way straps to the center hatch door

65.2. Raise the center hatch and store it next to the cage on the west main floor

65.3. Remove the 4 way straps

65.4. One person, with a safety harness and an SRL attached to the crane, must to attach the 4 way

straps to the left hatch door

65.5. Raise the left hatch and store it in on top of the center hatch


65.7. One person, with a safety harness and an SRL attached to the crane, needs to attach the 4

way straps to the right hatch door

65.8. Raise the right hatch and store it on top of the center hatch


Day 6 Complete


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Day7:LowerPrimaryMirrortoGroundFloor

1. Use the 4 way strap and the 50 ton crane to lift and move the chamber bottom through the hatch all

the way to the ground floor

1.1. Make sure to rotate the Chamber Bottom 90 degrees (the plug towards the chamber) before

setting it down on the rails on the ground floor

2. Drive the chamber bottom under the chamber

3. Remove the 4 way straps from the crane

4. Attach the Hydra‐Set to the 50 ton crane

5. Attach the 3 lifting fixture straps, and the 4 mirror cover straps, to the Hydra‐Set

6. Lift the mirror off the console floor (weight = 31.5 Kips) and lower through the hatch and place on

the 3 wash stands

7. Remove Mirror Lifting Fixture

7.1. Loosen the three pivot bolts on the lifting fixture

7.2. Remove the 3 locking bolts on the lifting fixture

7.3. Loosen and remove the three rods holding the lifting fixture arms in place

7.4. Rotate the arms to their park position and reinsert the locking bolts and rods

8. Raise and suspend the lifting fixture and mirror cover about 10 feet above the mirror

9. Lock out the dome and secure with a come‐a‐long

10. Repair broken edge supports (see Edge Support Repair Procedure Document: 9019‐A1).

Note: May take multiplel days

Day 7 Complete

Figure 39. Mirror Being Set on Washing Stands on Ground Floor


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Day8:Stripping,CleaningofPrimaryMirror,

Refer to NOAO Procedure for Removing Evaporated Aluminum Coatings from Glass or Glass‐Ceramic Mirrors: 7000‐AD‐010‐0001

The following steps pertain to stripping and cleaning on any mirror to prep for being placed in the aluminizing chamber for re‐coating the mirror.

Day9:AluminizationofPrimaryMirror

See Aluminizing Procedure Document:

1. Load mirror on Chamber Bottom.

2. Move mirror to chamber and aluminize.

Day10:AluminizationofPrimaryMirror(ContingencyTime)

Day11:Re‐Installationof4MeterPrimaryMirrorOptics:

1. Drive Chamber Bottom and mirror under hatch.

2. Lift mirror with 50 ton crane; store on east console floor.

3. Lift chamber bottom with 50 ton crane; store on east main floor.

4. Position triangular steel frame on chamber bottom.

5. Re‐install hatch covers and remove railing.

6. Position chamber bottom on hatch railing.

7. Drive Chamber Bottom to elevator.

8. Remove cell from telescope and position chamber bottom and PM cell on center hatch.

9. Clean and inspect PM cell and supports.

10. Remove edge support tie‐off cable.

11. Center primary mirror on top of cell using measurements from seismic plates.

Day 11 Complete

Day12

1. Connect axial supports to air regulator.

2. Install edge supports

NOTE: Check for alignment and proper operation.

3. Remove primary mirror lifting fixture.

4. Position PM on primary mirror elevator.


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5. Install primary mirror on telescope.

5.1. Use large guide pins.

NOTE: Use Chamber Bottom jacks for leveling cell (North and South).

6. Lower primary mirror elevator and position chamber bottom on center hatch.

7. Store primary mirror cover, lifting fixture, etc. on east console floor.

8. Position center baffle and cart on primary mirror elevator.

9. Install center baffle on telescope using guide pins.

Day 12 Complete

Day13

1. Install primary mirror axial dial indicator.

2. Load lower shell on chamber bottom using 50 ton crane.

3. Position on primary mirror elevator and install shell on telescope.

Note: Electronic Maintenance is to guide all cables and wires through proper holes.

4. Store chamber bottom on east main floor.

5. Remove 8” x 8” blocks and jacks from cage, position cage and cart on rails, and install cage on telescope.

5.1. Use guide pins.

NOTE: Counterweight motors have to be moved to install all bolts.

6. Install electronics racks (Electronic Maintenance)

Day 13 Complete

Day14:Installelectronicsracks(ElectronicMaintenance)

Day15:Installelectronicsracks(ElectronicMaintenance)

Day16:

1. Install rotator and guider (Instrumentation Group).

NOTE: Refer to Guider Rotator Removal/Install Procedure 2100‐AD‐015‐0026.

2. Install white adapter, alignment telescope and its fixture, and check centering and collimation with numbers from Day 1.

3. Store cage cart on west main floor.

4. Open hatch and lower all handling equipment (lifting fixture, cage cart, mirror cover, Chamber Bottom, wooden and steel triangular frames, etc.) to ground floor.


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5. Remove white adapter; align telescope and its fixtures.

6. Check Telescope Alignment.

7. Install scheduled instrument.

8. Install cage bottom per 2100‐AD‐015‐0015 4 Meter Cass Cage Bottom Installation Procedure.

9. Turn on telescope oil pumps.

10. Remove R.A. staybar.

11. Lower Cassegrain ramp to its normal position.

12. Install rails and wings on Cassegrain ramp.

13. Remove Dec staybar and steel angle bar.

14. Balance telescope.

15. Move telescope to SE annex, flip and install f/8 mask, flip to f/8.

16. Move telescope through its range of motion checking freedom of movement of radial support.

17. Move telescope to zenith. Turn primary mirror air on and off several times checking the response of mirror.

18. Turn telescope over to computer and instrumentation group.

Day 16 Complete

Day17:

Contingency

TelescopeCheckoutProcedure:

Refer to: Mayall 4 Meter Post‐Shutdown Telescope Checkout Document: 2100‐AD‐015‐0007


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RevisionTable

Revision Description Date Approved

‐ Initial Release 5/2/2014 Patrick Dunlop

A Added references to external procedures (ECR 201505‐0029 5/19/2015 Matthew Evatt

2100‐AD‐015‐0005 Mayall 4 Meter Primary Mirror Removal ... · 2100‐AD‐015‐0005 Mayall 4...

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