Mosbot

Mosbot is a python program that tries to adjust our observing scripts to adapt to changing conditions through the night.

Run it by logging in to the mzls@mayall-idl machine and then running:

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

You will need to keep that window open, because you want mosbot to keep running all night. pass{1,2,3}.json are the 'plan' or 'JSON' files that Arjun should have given you; they contain lists of exposures we want to take depending on what the conditions are doing. It is probably most convenient to run mosbot from a Terminal window on the mayall-2 display. You don't need to read any of the output it produces, but you should check periodically that it is still running; the code is under development and some bugs remain.

Mosbot Description

Mosbot does two things:

• On startup:
  • reads the pass{1,2,3}.json files given on the command line
  • discards exposures that are meant to be taken before the current time
  • writes an "overall" script for the night, ~/exec/mosbot/tonight.sh, which runs mini-scripts for each exposure
  • writes "default" mini scripts for each exposure

• Then:
  • waits for new images to appear in the $MOS3_DATA directory
  • when a new image appears:
    • measures sky, seeing, and transparency from the image
    • decides which pass number to observe in the upcoming exposures
    • computes exposure times for the upcoming exposures
    • overwrites the mini scripts for these upcoming exposures

The observers run the tonight.sh script on the mayall3 computer. Throughout the night, Mosbot overwrites the mini-scripts for upcoming exposures to adapt to the conditions.

How to stop and restart

If you want to stop and restart observing (eg, to take a focus sequence), you need to stop both the tonight.sh script, and Mosbot:

• to stop tonight.sh:
  

On the mosaic3 computer where you are running the tonight.sh script:

   touch ~/exec/mosbot/quit

The tonight.sh script checks for that quit file after each exposure, so it can take a while before it actually exits, but you won't lose any data this way. The tonight.sh script deletes that quit file just before it exits.

• to stop Mosbot, just ctrl-C it.

To restart,

• FIRST restart mosbot. It will write out a new tonight.sh
• THEN run the new tonight.sh script

During the night

To Restrict to Pass 2 and/or 3

If, say, the weather has worsened and is highly variable, then you can force Mosbot to always choose a given pass for upcoming exposures by creating files:

  touch ~/exec/mosbot/forcepass2

or

  touch ~/exec/mosbot/forcepass3

OR, if you want to forbid pass 1, but allow Mosbot to choose between pass 2 or 3, you can create the file:

  touch ~/exec/mosbot/nopass1

These files are NOT deleted by the tonight.sh script or by Mosbot, and will remain in effect until you delete them!

Note that it is Mosbot that pays attention to these files (not tonight.sh); they affect what it chooses to schedule for upcoming exposures.

Mosbot command-line options (not usually needed)

• --rawdata=RAWDATA Directory to monitor for new images; $MOS3_DATA by default
• --script=SCRIPTFN Write top-level shell script, default is ~/exec/mosbot/tonight.sh
• --no-write-script
• --ext=EXT Extension to read for computing observing conditions, default im4
• --tiles=TILES Observation status file, default obstatus/mosaic-tiles_obstatus.fits
• --pass=PASSNUM Set default pass number (1/2/3), default 2
• --exptime=EXPTIME Set default exposure time, default is to use whatever exposure time is in the JSON files, usually 80 sec
• --no-cut-past Do not cut tiles that were supposed to be observed in the past
• -h, --help - show this list

Comments:

• Mosbot by default starts with PASS 2 observations. And by default, we set all the exposure times to our minimum exposure time of 80 seconds.

• THEREFORE, if you kill mosbot after it has written out the tonight.sh script and run the default tonight.sh script, you will observe pass 2 with short exposures all night long. This is almost certainly not what we want to happen!!

• You can change the default pass number with --pass, and the default exposure time with --exptime. For example, if you are restarting in the middle of the night and you know the conditions are pass 3, you might want to do this. These default exposures are what will run ONLY until the first image is taken and appears on disk. After that, Mosbot will be choosing the pass and exposure time.

• The tonight.sh script is not smart. If you kill and re-start tonight.sh, you will start from the beginning of the night (or the last time Mosbot was run). If you have to stop the tonight.sh script, PLEASE re-run Mosbot to regenerate an appropriate tonight.sh script.

• The tonight.sh script writes to a file ~/exec/mosbot/seqnum.txt to indicate which exposure it is currently running. The mosbot.py script reads that file to figure out which upcoming exposures it should update. Mosbot by default writes exposures 1 through 10 ahead of the current sequence number.

• Each exposure is split into two scripts. For example, exposure 3 happens in expose-3.sh, which takes the exposure, and then slewread-4.sh slews to exposure number 4 while reading out exposure 3.

About git:

• the ~/obsbot directory is a git checkout of the repository: ​https://github.com/legacysurvey/obsbot
• There is a "MzLS Observer" github account set up to log in with an ssh key, so you should be able to *git commit* and *git push* any code changes without having to know any passwords.