SHARP SETUP AND BREAKDOWN

How to set up at the start of a SHARP run, and break things down at the end

Giles Novak, Oct. 2006
John Vaillancourt, updated Nov. 2006
Darren Dowell, version 3, Apr. 2007 -- default HWP angles, uipd.com command
Giles Novak, version 4, April 2008 
Giles Novak, version 5, June 2008 -- added SHARP removal instructions
Giles Novak, version 6, April 2010 -- cleaned things up a bit 
Giles Novak, version 7, October 2010 -- fake observing, other minor changes 
Giles Novak, minor updates, November 2013 -- removed fake observing details providing reference to new document
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A. SET-UP TASKS: 

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(A1) Find stuff and unpack it

 - locate SHARP boxes not mounted, bolts to connect SHARP boxes

 - unpack boxes; inspect everything, e.g. mirrors 

 - locate aperture plates (grey disks) -- in wooden cabinet in lounge

 - locate LN-2 cold load (bucket with two tubes sticking out) and its bracket 

 - locate safety harness.



(A2) Install all SHARP boxes except for Box 4

 - Box 1 is usually always mounted.  A few notes in case it is not:

      - front screw for Box 1-to-0 washer does not fit

      - hold-down bolts that secure Box Zero to Box 1 should not be over-tightened.  

           - If they are over-tightened, box 1 bottom plate could get bent.

      - the height and lateral translation of Box 1 should be set as follows:

           - vertical gap between box 0 and box 1 has typically been about 0.13"

           - the front edge of Box 1 is separated by 2.375" from front edge of Box 0

                - by "front edge" we mean the edge that faces SHARC-ii 

           - when you are done, the gap between Box 4 and the M4 box should be about 1.1"

 - Box 2 and Box 3 are easiest to install with the help of the day crew using the crane

      - Ed and Steve have helped with the crane in the past

      - Identical bolts are used for Box 4 to Box 3, Box 3 to Box 2, and Box 2 to Box 1

      - Special instructions for Box 3 (see also the SHARP installation video): 

           - set it down vertically with HWP module extension pointing toward the telescope

           - then flip it forward 

                - this works best with one person on either side

                - use the harness for the person on the far side, of course

      - Box 2: Two countersunk bolts secure Box 2 to Box 1.  These are inside Box 2

      - Box 3: Two countersunk bolts secure Box 3 to Box 2.  These are inside Box 3


 - OPTIONAL: Level the boxes using NU electronic level (both axes).  

NOTE 1 ON LEVELING: Remember to rotate level 180 degrees and take an average of the
two measurements. This is because of zero-point offset of level. (Alternatively, 
there is a way to null this.)

NOTE 2 ON LEVELING: To fix any leveling problems you will probably have to remove 
boxes, then adjust the 3 screws on the bottom of box 1, then add the boxes back and 
re-check.  Such adjustments will requires loosening the "hold-down"screws bolting 
box 1 to box 0.  Remember to re-tighten but DO NOT overtighten - see note above.  
Also, the hold-down bolts prevent the front-heavy SHARP tower of boxes from tipping 
over, so beware of adjusting the hold-down bolts unless all boxes above Box 1 are 
removed.


(A3) Hook up the HWP electrical connections

NOTE: you may want to refer also to Megan's document "HWP Control Box"

 - first connect white ethernet cable and AC power to HWP control box

 - (don't turn on the power switch however)

 - ensure that EDAS analog outputs (angle and stat) are connected to the SHARCII data system.

 - locate the BNC cables that run to the HWP heaters

 - put on the harness and climb over to the far side of Box 3 

      - bring wire clippers, electrical tape, cable ties, run heater BNCs through 

 - connect the encoder, motor, and heater cables to Box 3

 - the encoder connector is fragile and its pins are easily bent, so take your time; be careful



(A4) Test HWP motion 

NOTE 1: see also Megan's document "HWP Control Box"

NOTE 2: see also "SHARP Troubleshooting" that discusses failure modes

There are two ways to test the HWP motion (the first is the usual way):

I. using client/server (leave HWP box set to EDAS-mode)

 - do a few test moves

 - make sure that analog hwp angle is recorded in data files 

      - see SHARP cheatsheet for instructions on how to do this check

II. using paddle (need to set HWP box to paddle-mode):

 - Power on

 - type "space" followed by "CR".  This will give you the "#" prompt

 - type "+/- number" followed by "CR" to move HWP.


NOTE: you can check the HWP heaters with an Ohm-meter


(A5) Install Box 4, all remaining box side-covers, and set up HWP heaters

 - Install box 4 (see separate document on installing and removing box 4)

 - OPTIONAL: Perform SHARC-II beam alignment before installing box 4. 

      - see separate document: "SHARP alignment instructions"

 - OPTIONAL: After box 4 is on, level in center of box.

      - do this along both long and short horizontal axes.

      - see "NOTE 1" and "NOTE 2" on leveling, given above

      - typically, box 4 tilts downward by 0.1 degree and we ignore this problem

 - OPTIONAL: To check the translation, mount NU laser on the front of box 4

      - laser emits a beam along SHARP chief ray.  

      - test centering by using the grey exit aperture disk 

           - this disk installs into the elevation tube during SHARC-II alignment tests

      - height and lateral degrees of freedom are adjusted in Box 0 and/or Box 1

 - check that that clearance between box 4 and M4-box is set to the value given in the above 
   instructions for mounting Box 1.

 - check clearances to counterweight at hwp module, box1, box zero, etc, for various 
   different elevation angles.

 - install cardboard side panel to Box 3 

 - install and test HWP heater power supplies

      - one of them has a broken current meter (intermittent) 


(A6) Test the system via "fake observing" to make sure all computers are talking:

It is a good idea to make sure that all the computers are talking.  One way to do this is to 
do "fake observing".  This can be easily in the day-time without moving the telescope much.  
It can be done with or without the chopper.  Instructions for fake observring are posted 
separately on the teamsite.  At the conclusion of "fake observing" you should shut down the 
system so that you can later start it up in "real observing" mode.

In case of problems during fake observing, here are some details that may be good to know:

EDAS i.p. number should be: 128.171.86.86.

EDAS has now has two versions of code written by Peter: "dummy" and "real".  The default 
is "real".

To change the startup hwp angle in IRC, edit the following line in

sharcii:/home/sharcii/sharc/irc/v1_8/app/server.plist:
     # initial angle in tenths of degree
     sharc.polarimeter.initialAngle=500

to change default values for IRC scripts, edit the file

kilauea:/home/kilauea/sharc/.irc/sharc_v1_5/resources/sharc/xml/default_command_procedures.xml


(A7) Carry out SHARP alignment: see separate document called "SHARP alignment instructions"


(A8) Test data analysis code: see separate document on "rough mountaintop data analysis"


(A9) Miscellaneous

confer with previous observers and day crew - is SHARC-II, tau-meter, and
CSO working OK?

 - To fix tau meter see Hertz web page

   (http://astro.uchicago.edu/polar/Hertz/taumeter.html) or type: TYPE
   SYS$NEWS:STARTING_TAU_METER.TXT at a UIP> prompt


(A10) Test the chopper.  


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B. GRID TESTS (See also John's document "Measuring the HWP zero-angle...":

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NOTE: When mounting the calibration grids on the gray aperture plate, tape
only onto the long sides of the grids.  Do not tape the solder/glue on the
short end.  In the past, this glue, along with a few grid wires, have 
come off when removing the tape.

Use grid mounted to plastic disk, at the "M3-end" of the elevation hole.

(B1) Measure HWP every run:

Measure "HWP" (zero angle flag in John's code), by measuring V-null (see
posting to logbook dated Aug. 30, 2006).  Grid wires should be vertical.

(B2) Check rotation direction and efficiency, every other run:

Measure V-null with grid rotated from vertical position by roughly 20
degrees.  Rotation should be clockwise, as viewed from M3.

Take a full hwp cycle in engineering mode with Grid wires vertical.

Repeat with grid wires roughly 45 clockwise, and roughly 45 degrees
counter-clockwise.

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C. ON-SKY TESTS:

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(C1) Faint point-source (Uranus in Fall '06)

pointing offsets for both H and V (adjust to match if needed)

focus

beam size with chopper on and with chopper off 


(C2) IP calibrator (Saturn, Jupiter, and/or Mars):

need 50 cycles, equally spaced over a 50-degree range of elevation


(C3) RGM 


(C4) H,V alignment, and relative rotation, scale: Darren's software


(C5) During observations, monitor beamswitching accuracy, half-wave
plate accuracy, and L/R balance.  See cheatsheet for details.


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D. AT END OF RUN:

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There are two possibilities as far as how much of SHARP comes off:


(1a) Only box 4 off:  

- remove and store brackets (that connect box 4 to M4-box) and associated 
hardware

- remove box 4 - usually it is held by two bolts kitty-corner

- Install the metal cover on top of box 3


(1b) Boxes 2, 3, and 4 off:

remove box 4 (see above)

remove box 3: 

- first harness up and climb around to the far side of SHARP to disconnect the 
motor (military connector outside of box 3), encoder (black plastic connector 
attached to encoder which is on the hwp module plate), and two BNC cables for 
heater voltages.  Make sure hwp box and hwp heater power supplies are powered 
down before disconnecting these.

- as shown in the video (on SHARP teamsite page) there is a specific method for 
removing box 3.  The idea is to first stand it up on its back end.  Then use the 
hoist (with Ed's help) to lift it off.  (This can be done without the hoist but 
the hoist is much preferred.)  Box 3 is also held to Box 2 by two bolts.  As 
shown in the video, you need to have one SHARP investigator on each side of box 
3, so this requires one person to harness up and go around to the far side of 
SHARP.

- remove box 2 (also held by two bolts)

- install the cover onto box 1.  This is cardboard and labelled as "cover to box 
1 or box 3".


(2) other things to do:

- after powering off the HWP box, unplug the hwp AC cord and ethernet cable

- pack the grids carefully as shown on the SHARP video (teamsite page)

- Store SHARP, and label crates as "SHARP boxes: Do not move without
contacting Hiroko Shinnaga or Giles Novak".   

- Some stuff may need to get shipped or hand-carried back to NU.  Contact Giles.

- Note the location all shipped, hand-carried, and stored items onto the 
inventory document on the teamsite.  Especially, don't lose the bolts needed for 
the box 4 brackets and to bolt the boxes together.  Also don't forget to pack the 
heater power supplies.

- Make sure that the grey disks (both of them) get back in the SHARC-II drawer in 
the lounge, and put the cold load bucket and its bracket in the receiver side-cab room.

- E-mail spreadsheet logbook to data analysis group.