OBSERVING INSTRUCTIONS FOR MzLS

Still need to incorporate the following instructions:

• Running the guiding loop -- although we typically do not guide on the Mayall for these 1-2 min exposures
• Coverage plots, which we've not yet ported from the DECam version

These are instructions for observing for MzLS.

---

VERY VERY IMPORTANT

1. DO NOT OVEREXPOSE MOSAIC CCDs to LIGHT!

Prolonged exposure can damage and even destroy the devices. The following rules are in effect:

1. Operation on sky is restricted to between 12 deg twilights.
2. Operation is restricted to when OAs or other NOAO technical/scientific staff are present
3. The cameras and MOSAIC software should be shut down when observing / NOAO personnel are not present
4. Sky values should be kept < 40,000 adu (<30,000 adu is preferable).

2. PLEASE TALK TO THE OAs ABOUT SAFETY AT THE TELESCOPE

1. Do not leave the control room at night without telling the OA
2. Do not go into the dome without the OA's permission
3. Do not go exploring by yourself
4. Carry a flashlight and radio at night

---

Read the Manual for MOSAIC operations

To see the Mosaic1.1 manual, go here: ​http://www.noao.edu/kpno/mosaic/manual. Mosaic3 also runs NOCS. We'll hopefully have an updated manual soon.

Some Preliminaries

Observing can only be done from the Mayall control room or from within the KPNO/NOAO network using a VPN.

The telescope and low-level instrument control runs on ​observer@mayall-2.kpno.noao.edu . Log on to the mayall-2 computer:

Username : 4meter
Password : <Ask someone on our team or the staff>

To run MOSAIC3, use the MOSAIC3 Menu GUI. Or you can also log into the mosaic3 computer from mayall-2:

ssh -XY observer mosaic3

and use command-line nocs commands.
PLEASE BE CAREFUL ON THIS COMPUTER - IT RUNS THE CONTROLLERS AND THE INSTRUMENT!!'''

Our observing scripts and data reduction runs on ​mzls@mayall-idl.kpno.noao.edu :

Username : mzls
Password : <Ask someone on our team or previous observers>

These environment variables define the locations of data and code:

$HOME=/home/mzls
$MOS3_DATA= -- This is where our raw data files are written. Should be something like /mosaic3/data2/observer/20160202. This is a network mounted disk on the machine mosaic3.
$MOS3_OBS=$HOME/products/mosaic3 -- This contains the observing product with code and versioned log files.
$PS1CAT_DIR=$HOME/ps1/chunks-qz-star-v2 -- Pan-STARRS1 catalogs used by the IDL DECSTAT routine for computing astrometric offsets and photometry

These path names are set in the .bashrc file, or can be set for example with "export MOS3_DATA=/mosaic3/data2/observer". The $MOS3_DATA directory must be updated to point to the current night's data.

Other directories in the home directory are:

astrometry/, legacypipe, obsbot, tractor, wcslib -- Python code for running copilot
data/ -- Link to the top-level data directory, where each night is stored in subdirectories like "20151213"
exec/ -- Cross-mount to mosaic.kpno.noao.edu:/home/observer/exec
products/ -- Code checked out from the SDSS and the DESI svn repositories

Documentation for the IDL scripts can be printed from the IDL prompt with the DOC_LIBRARY command, for example:

      idl
      IDL> doc_library,'mosstat'

Date convention

All dates in log files are set to the local date of the beginning of the night. For example, any data taken during the night of December 13/14, 2015 will be written as 2015-12-13. This is consistent with how the NOAO Science Archive timestamps and saves the raw data files.

Are we there yet?

The tiles we’d be observing with MOSAIC3 in z-band are tracked in the file ~/products/mosaic3/obsstatus/mosaic-tiles_obstatus.fits with the following cuts:

  IN_DESI = 1
  DEC >= 30
  88 < RA < 301
  PASS <= 3

That’s 44,422 tiles. This will likely be further limited further to the 41,188 tiles at DEC >= 34. About 5% of the tiles have been removed from the list where there's a star brighter than V=6 within 0.35 deg of the tile centers.

---

EXAMPLE RUN THROUGH FOR A GIVEN NIGHT

---

[1] Update everything

Log into the mzls account on the mayall-idl machine.

Update the code, log files and most importantly the tile file:

cd ~/products/mosaic3
svn up
cd ~/products/observing
svn up

[2] Set the paths

The data path must be changed to point to the current night's data. Edit the entry for MOS3_DATA ~/.bashrc file, for example if the start of the night is 13 Dec 2015 change this to

export MOS3_DATA=/mosaic3/data2/observer/20151213

[3] Create nightly plan

Arjun should have provided you with 3 nightly plans for each night, one for pass 1, one for pass 2 and one for pass 3 observing. These have tiles that should be observed under different weather conditions as described at MayallZbandLegacy/ObservingStrategy .

Instructions for creating these files is at MayallZbandLegacy/NightlyStrategy?

[4] Start up mosaic control software

On mayall-2, double click on the MOSAIC3 icon, which brings up the MOSAIC3 Menu on the left edge of the screen.

1. Start the camera control program by pressing the yellow "Start Cameras" button. Wait for this to finish, then dismiss the screen by typing any key as instructed
2. Start the MOSAIC3 NOCS software by pressing the blue "Start MOSAIC" button. This launches a blue xterm. Move it out of the way and watch all the windows come up
3. Rearrange the desktop as needed.

If, for some reason, the buttons do not work, you can start up the software on a command line as follows: On mayall-2 open a terminal window and:

ssh -XY observer@mosaic3
nocs start ccp (this is equivalent to the "Start Cameras" button on the MOSAIC3 Menu)
nocs start all (this is equivalent to the "Start MOSAIC" button on the MOSAIC3 Menu)

Once nocs is up and running, rearrange windows as desired, and check the status of the system by typing the following in a nocs terminal window:

nocs status all
nocs fullstatus ccp

4. Launch CCD temperature monitor from "MOSAIC Temps" icon (CCD and Dewar temps should be around 173C and 90C respectively)
5. Launch TCS acorn monitor from "VDU" icon
6. 4MAPS monitor from "4MAPS" icon
7. Launch Truss temperature monitor from "Truss C" icon

All these icons are on the right side of the left hand screen of the mayall-2 computer display. Rearrange the busy desktop as needed ...

[5] Set the PROP-ID and Project Info

On the NGUI window, press the "Set Project" button and fill out the relevant information. For example,

Principal Investigator: Arjun Dey
PIs Email Address: dey@noao.edu
Actual Observers: Tristram Shandy, Bertram Wooster
Observing Assistant: Karen Butler
OA's Email Address: 4meter@noao.edu
Proposal Identifier: 2016A-0453
Telescope System: KPNO Mayall 4m
Science Instrument: Mosaic 3

Please ensure the Proposal Identifier number is correct''

Then, in one of the NOCS xterm windows, type: "nocs set project"

[6] Take a test image to ensure system is working

Check that all is well by taking a test zero exposure. On the IRAF window, check the image statistics by cd-ing to the correct directory and typing "mscstat <filename>" All rms values should be about 4-6 adu/pix; the exception is amplifier [6] which has an rms~8-10adu/pix. If any one amplifier shows very high noise, then execute the following commands in a nocs window:

nocs reset ccp
nocs init ccp

Then take two more zeros; the first one will be junk, but the second one should be OK.

[7] Take dome flats and zeros

During the afternoon (after 4pm), take dome flats with the telescope pointed at the white spot.

1. Check that telescope is pointed to the white spot with mirror cover open
   
2. Take 10 zero exposures
   
3. Turn on low dome flat field lamps at 100% intensity (~50V)
   
4. Create a dome flat script using the NGUI interface. Exposure times as follows:
   

z-band : 20 sec
r-band : 25 sec
g-band : 20 sec

Take 11 flats in z-band every night; only take flats in other bands if you intend to use them. Counts should be ~18-20k adu.

5. Take 20 zero exposures
   
6. Go eat dinner
   

[8] Just before observing

1. Start the automated script for updating the tile file

The FITS file listing which tiles have been completed should be updated throughout the night. This file is $MOS3_OBS/obstatus/mosaic-tiles_obstatus.fits. The following IDL command will monitor exposures as they are taken throughout the night, automatically updating this file. From a terminal on the mayall-idl compute, in the mzls account, start this running:

idl
   muptiles

At the end of the night, you should check the updated tile file into the svn repository.

2. Start the automated script for monitoring the data quality

From another terminal in the mzls account, start this running:

idl
   mosstat_continuous

This will run mosstat on each frame as it shows up and display the results on the screen.

[9] Observe - start of night

No on-sky observations are permitted before 12 deg twilight.

1. Take a zero image to ensure everything is working
2. At start of night, check telescope pointing and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane).
3. Move to the beginning of the first MzLS tile position
4. Focus the telescope
   • create a focus script using the NGUI
   • run the focus script from the /home/observer/exec directory
   • analyze the focus image using mscstarfocus
     • edit the mscfoc.cl script to correct the name of the image that needs to be analyzed
     • mark about 10 stars around the image; mark the top star in each sequence using "m"; "q" to quit
   • log the Truss temperature
   • set the telescope focus
   • focus the guiders; this way you can use the guider images to monitor focus drifts

Example of a focus sequence

Observe - all night long!

5. From the mzls@mayall-idl window, generate the top-level observing script (tonight.sh) assuming that we have three plan files named pass1.json, etc.

      cd ~/obsbot
      python mosbot.py pass1.json pass2.json pass3.json
   

This will start the mosbot script, which will watch the $MOS3_DATA directory for new images, analyze them, and update FUTURE exposure scripts, choosing the pass number and setting the exposure time.

See MayallZbandLegacy/NotesforObservers/MosBot

6. From the observer@mayall-3 xterm window, start taking exposures using the top-level observing script (tonight.sh):

      cd ~/exec/mosbot
      ./tonight.sh
   

7. Start running "copilot", which is the thing that keeps a beautiful running plot of observing conditions. From any mzls@mayall-idl window:

      cd ~/obsbot
      python copilot.py
   

Whenever a new image is detected in the data directory (as defined by $MOS3_DATA), a new image is generated as ~/obsbot/recent.png . That image can be displayed by anyone that can see this directory. It could be displayed with continuous updating with

   eog ~/obsbot/recent.png

8. Monitor focus by checking the image quality on each frame. Keep track of the truss temperature variation and modify the focus as needed. The Mayall has astigmatism, so one can tell from the shape of the images which way to move the focus. To stop and do a focus sequence:

• Create a file to tell obsbot to quit

     touch ~/exec/mosbot/quit
  

• Wait for the current exposure to complete (at which point the above file is automatically removed)
• Run a focus sequence (DESCRIBE THIS)
  • Example of a focus sequence
• Re-start the observing as described above. *IMPORTANT* make sure to re-run mosbot.py so that you don’t repeat exposures from the beginning of the night!

Keep an eye on the CCD and dewar temps (should be around 173C and 90C respectively)

If you have problems …

See MayallZbandLegacy/NotesforObservers/Problems

Checking the Sky Brightness, Seeing and Transparency

The "copilot" python script mostly deprecates this, but we have IDL code for analyzing the images.

From an IDL prompt, use the MOSSTAT routine to analyze the latest image on disk:

   IDL> mosstat

There are keyword options that allow you to choose different exposure numbers or CCDs within that exposure. For example, to analyze chip 'im16' of the exposure number 12345, type:

   IDL> mosstat, 12345, ext='im16'

The full documentation can be seen with:

   IDL> doc_library,'mosstat'

To just have mosstat run continuously whenever each image appears, use

   IDL> mosstat_continuous

Please write useful human logs

Keep a log about weather conditions, which pass you observed, and telescope problems. Follow the example on the pages at MayallZbandLegacy/ObservingLogs .

Catastrophically bad frames (such as saturated frames, or where the telescope moved) are recorded and svn-checked-in to ~/products/mosaic3/logs/bad_expid.txt .

[10] End of night

No on-sky observations are permitted with MOSAIC3 before 10 deg twilight or after 10 deg dawn. No twilight flats are allowed.

Shut down the software

1. Ensure that the "Shutter" and "ready" are both in the "Dark" position on the MCCD gui
2. Press the red "Stop MOSAIC" button on the MOSAIC Menu GUI. Wait for this to finish.
3. Then press the yellow "Stop Cameras" button on the MOSAIC Menu GUI.

If the buttons do now work, then go to one of the NOCS xterm windows and type:

     nocs stop all (equivalent to pressing the "Stop MOSAIC" button)

Once nocs is shut down, type

     nocs stop ccp (equivalent to pressing the "Stop Cameras" button)

Once this is done, type

     nocs status all
     nocs fullstatus ccp

and make sure everything is shut down. Only when this is done, is it safe for the OAs to put on the lights in the dome.

Check in the updated tile file

At the end of the night, you should check the updated tile file into the svn repository. On the mayall-idl computer:

   cd $MOS3_OBS/obstatus
   svn commit obstatus/mosaic-tiles_obstatus.fits --username <YOUR-NAME>

Create the Almanac and Almanac plot files

At the end of the night, create the Almanac files and check them into svn.

- cd products/mosaic3/logs
- idl
- almanac,<first exp num>
- plotalmanac,'Almanac_date.fits',ps='plot_Almanac_date'
- exit
- svn add *Almanac_date*
- svn commit *Almanac*

For example, for the night of March 26/27, 2015, this is done with:

cd products/mosaic3/logs
idl
   almanac, 424978, 425143
   exit
svn add Almanac_2015-03-26.*
svn commit Almanac_2015-03-26.*

There are actually two versions of this file, one that is an ASCII file (with .txt extension) and one that is a FITS file (with .fits extension).

Thank the OA and go to bed

---

Pages linking to PublicPages/MayallZbandLegacy/NotesforObservers:

• MayallZbandLegacy
• MayallZbandLegacy/NotesforObservers
• MayallZbandLegacy/ObservingSchedule
• MayallZbandLegacy/Run08
• MayallZbandLegacy/Run13
• PublicPages/MayallZbandLegacy
• PublicPages/MayallZbandLegacy/NotesforObservers/Copilot