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| 1. Remove the witness samples |
Remove the telescope cover and
recover the witness slides stored at the top of the
focus motor housing next to the flat field lamp.
Put them in a labeled envelope ("on telescope until DATE")
and put the envelope in the PT filter storage box
(in the computer room).
Replace the telescope cover.
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| 2. Pin the DEC axle |
Insert the DEC lock pin.
The pin is stored in the toolbox in a labeled drawer.
The DEC pin is the longer of the two and has a really long flag.
The telescope may need to be jogged a bit north or south to do this.
Once pinned, it's important that you don't run the drive motors
to avoid damaging the drive disk.
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| 3. Release the DEC drive.
| Unscrew the DEC axle tension screw
until all pressure is off the drive wheel and the telescope
wobbles freely N-S.
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| 4. Pin the polar axle |
Insert the short pin into the
hole on the front of the polar axle drive wheel cover.
You may need to jog the telescope E-W to line it up.
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| 5. Turn off drive power |
Turn off power to the telescope
motors (HALT MOTORS button IN, DRIVES switch OFF).
There is no need to turn off the motor driver chassis power
and you should not turn off the main power switch.
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| 6. Remove the dewar |
See Jon Brinkmann.
Power off the CCD controller.
Disconnect the ion pump power cable.
Disconnect the saddlebag cables (leave the
saddlebag on the dewar).
Undo the CryoTiger hose clamp on the west side DEC axle.
Clip off the hose clamp tiedowns on the fork.
Remove the dewar.
Do not move the three centering screws; the dewar
will come out easily if allowed to move straight down.
The dewar should be stored safely out of the way,
pointed up with a cover over the lens.
Don't point it down or sideways; this will keep
dust off the CCD.
Legs can be attached to the dewar sides and the
feet screwed into a small optical bench.
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| 7. Install bottom cover |
This round plate (labeled "moth blocker") is stored
in the bottom drawer of the toolbox.
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| 8. Disconnect the filter box air hoses |
See Jon Brinkmann.
First remove the high pressure air supply by disconnecting
the quick-release air line (red hose) just to the left of
the regulator feeding the flow meter on the east wall of
the dome (photo).
The other end of this hose can then be disconnected at the filter box.
Then disconnect the purge air hose at the filter box.
You should leave it running or plug the end of the hose
after turning it off.
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| 9. Disconnect filter box cables |
Disconnect the shutter and filter wheel cables from the south
side of the filter box.
Secure the cable ends out of the way.
Also unscrew the cable clamp on the side of the filter box
(the one that holds the saddlebag cables) and secure those
cables out of the way.
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| 10. Prepare hydraulic lift |
Unbolt the expanded metal platform from the steps
and from the lift. Lift it off and set it aside.
Place spreader bars across the forks of the lift,
positioned to support the filter box.
Raise the jack up underneath the filter box, checking
to be sure the spreaders are correctly located to
securely support the filter box.
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| 11. Remove the filter box |
Unscrew the bolts connecting the filter box to
the telescope primary mirror cell.
Lower the lift and the filter box;
cover it with a large plastic bag;
then store the filter box on blocks
located on the table top.
The blocks are needed to keep the dewar clamps
off the table.
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| 12. Remove corrector lens |
Remove the twelve large cap screws
holding the C1 corrector.
Store this in a covered box.
Clean the lens, if needed, before reinstallation.
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| 13. Remove primary baffle |
Unscrew this from the back of the
mirror cell (four small cap screws).
It's nearly two feet long.
Pull it straight out to avoid scraping the paint.
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| 14. Remove three large plugs |
There are three rubber plugs with metal clips that fill
the large diameter holes in the primary mirror cell.
Remove these.
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| 15. Release Invar spacers |
Remove the four 1/4-28 cap screws
(see page 26 of the PT logbook) that are at the extreme
circumference of the back of the mirror cell.
These screws connect to four Invar rods inside
the telescope tube.
The rods will hang in place when you remove the primary cell.
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| 16. Attach lifting brackets |
Remove the two lifting brackets from the bottom drawer
of the rollaway along with qty. 6, 3/8-24x1" cap screws
from the "inst. bolts" container. With three of the cap
screws attach the smaller triangular piece to the bottom
surface of the cell, on the north side of the cell, pointed
away from the telescope fork. The hole near the tip of the
triangle should be directly above the north fork of the
lift. Attach the larger piece to the hole pattern on the
bottom of the cell opposite the pattern used for the small
triangle. The outer edge of this bracket should be directly
above the south fork of the lift.
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| 17. Attach the lift |
Remove the 3 long steel standoffs from the bottom drawer
of the rollaway (1" hex bar 10" long, plus threads
on both ends).
Screw the short end of the standoffs into the tapped holes
in the forks which align with the holes in the brackets
installed in the previous step.
With an inverted flange nut and a flat washer on the
upper threads of the standoffs, pump the jack up until
the standoff threads are thru the lifting brackets and
the jack is pushing up on the cell with about 40 lbs.
at each standoff.
The nuts can be adjusted as needed to equalize this load.
Install nuts on the top of the standoffs.
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| 18. Set up the rollaway |
Remove the upper tool box from the tool box/rollaway
set and set it aside. Place the rollaway between the
forks of the lift, directly under the telescope. Arrange
the mirror tripod on the rollaway with the nylon pads up
(the pads will support the cell) and in a way that guarantees
that the feet will not go through the holes in the mirror cell.
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| 19. Detach mirror cell |
Remove eight 1/4-28 cap screws that
hold the mirror cell to the telescope center section.
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| 20. Lower the cell |
The four Invar rods extend about eight inches from
the telescope's center section so slowly lower the
cell until these are clear of the cell.
The primary mirror cell should come to rest on top
of the mirror tripod stand; do not let the tripod
legs pass through the mirror cell.
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| 21. Touch up the black paint on the rods |
Check the Invar rods for shiny spots where the paint
has fallen off and apply some flat black spray paint
if needed (paint doesn't stick too well to these rods).
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| 22. Remove earthquake restraints |
Remove the four triangular mirror "bumpers" from
the front inside of the mirror cell.
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| 23. Measure and record the mirror edge depth |
Wipe clean the top surface of the mirror cell and
attach the steel reference plates.
Use the depth micrometer to measure the primary
mirror position (photo)
at the three locations.
The correct distance is 4.555 inches at all points.
Record the actual numbers in the log book.
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| 24. Loosen two transverse supports |
Loosen two of the transverse support cylinders using
the Allen-head screws centered in the black disks around the outside of
the cell. If you loosen only two, say those at the west and north, then
the mirror will return to approximate collimation upon reassembly.
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| 25. Remove the mirror |
Jack up the cell and mirror off of the tripod;
rotate the tripod until the legs line up with the large holes in the
bottom of the cell; then gently lower the cell over the tripod. The
mirror will be left sitting on the tripod at the top of the cell.
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| 26. Box the mirror |
Move the mirror from the tripod
into its gray foam-lined plastic storage case.
Keep the optical surface up and do not turn the box over
during the move to the Sunspot coating chamber.
Cover it with tissue before closing the lid.
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