This is a summary of normal IGRINS use for queue observers at Gemini South Telescope.

Observing timelines: 

  • An hour before sunset, begin the Start of the Night procedures.
  • 30 minutes before sunset, take calibrations.
  • 20 minutes before 12 degree twilight, your SOS will open and perform tuning if the weather is good. This should take 20 minutes.
  • at 12 degree twilight, your IGRINS on-sky time begins (nightly observing procedures).
  • at most, you can observe 50 minutes until sunrise.
  • when your SOS is ready, you will take calibrations (about 30 minutes).

    The order of operations should be  test, darks, flat offs, flats ons (this order is necessary to reduce persistence from the flat lamps on the calibrations), science.

Start of Night:

1. Wake up the observing iMac and login.

2. From the iMac: Screen share to the ICC. From the screen sharing program, open another screen share connection to the DSC. If this one isn't loading well, change the "view" tab to "full quality". After it loads, change back to "adaptive". Everything else following will be done on the ICC or DSC through the screen sharing.

3. On the DSCTurn on the IG proxy.

> cd ~/igrins_admin
> sh
When it launches, the proxy window will pop up. Leave the rotator box checked.

If the VII connection is working, you should see the heart symbol beating and correct coordinates displayed. If it is red or otherwise, you have to ask the SOS to restart the VII.

4. On the ICC: Close the HPK and IGRINS Hub windows on the Desktop if they happen to be open. There are several scripts you must begin now, each in a new terminal window.

  • Typically, begin at (c). (a) and (b) should already be done, but just in case are described here.

 a. Mount the detector computers

 > cd ~/igrins_admin
 > sh mntrun

b. Upload the temperatures to the web with firebase

 > cd ~/igrins_admin
 > sh

c. Turn on the IG software (HKP house keeping package, SCV slitview camera, DTP data taking package) by opening a new terminal and typing:

> cd ~/igrins_admin
> sh
When it launches, the "IGRINS Hub" window will pop up.

You should see the "check Mount" and "check Proxy" change from "..." to "Okay" status.

Start the HKP (click "run HKP"). In the HKP gui, click the “periodic monitoring”  and, below that, the “Send Alert (T>20)” buttons.

Once you see that the HKP status says "connected" in the Hub, start the SCP (click "run SCP"). You should see the SCP window pop open.

Once you see that the SCP status says "connected" in the Hub, start the DTP (click "run DTP"). You should see the DTP window pop open.

d. Turn on the ICC audio  

> cd ~/igrins_admin/misc
> sh
Once you run this, then you can open a browser on the observing iMac. Make sure to push play on the bottom and that the speaker on the iMac is on!

e. Fill the digital logs

> cd ~/igrins_admin/misc
> sh 2018A_Gemini

 It will pop open a web browser with the log opened.

5. On the ICCCheck the software

In the SCV, check if you are receiving the TCS information or not (blue values on the upper right, including RA, Dec). 

Note -  TCS will not be running without your TO. Images and cals can still be taken but headers will be incomplete.

In the Status box, the following lines (for the SVC, and then for both H and K in the DTP) should appear:

      •  “[time] NFS connection succeeded”
      •  “[time] Detector Status Check”
      •  “[time] Detector is Ready” 

6. Test Exposures

Change the observer name to your Last Name. No single quotes or special characters. Commas are ok.

Change the object name to 'test'.

Take a test image on both SVC and with the HK detectors to test readout.

      • Turn off ‘automatically save’ if you prefer
      • Use shortest exposure 1.63s

If you see noise pattern or low-resolution image, repeat the short exposures or contact observing support.


The recommended calibrations are listed in the following table, and the procedure below. It should take ~25 minutes in total.

You should get 10,000 counts in the H band and 8,000 in the K band. You must have more than 4,000 and no more than 20,000.


Typeexposure time (s)numberNumber of Fowler Reads
Flat off10106

Flat on


※ How to put the program ID into fits headers of IGRINS daily/SKY calibration frames

'Daily calibration' is usually the first frames of each nights.

Procedure to put Program ID:

  • We use pseudo object named ‘GCAL IGRINS Dark/Flat-off/on’ in OT.
  • Copy object ‘GCAL IGRINS Dark/Flat-off/on’ from 'IGRINS Calibrations and Tellurics library' or daily calibration programs of previous IGRINS nights.
  • Paste ‘GCAL IGRINS Dark/Flat-off/on’ to today’s daily calibration program.
  • RA value should be similar to current LST. (wrong coordinate doesn’t cause any errors but this makes the SOS’s work easier.)
  • All required setting for the calibration is listed in the 'Yellow Note' of the object.
  • after click Queue in OT, tell SOS that we want this program ID but telescope need to be stayed at Zenith.
  • now you can follow the process below.

1. Darks

Check all the lights are off around the telescope.


    • dome is closed
    • fold mirror parked
    • mirror cover closed
    • all lights are off

Using the DTP, take darks:

  • OBJ name = DARK, OBJ type = DARK
  • Click automatically save to save images

 Don't forget to start the paper observing log.

2. Flats

Ask your SOS to:

    • unpark the fold mirror and put it so that it is in position for the GCAL lamps (“GCAL 2, visitor 4” is the techinical)
    • use the ND1 filter

A. FLAT OFF: Take flat offs before the flat lamps are on (required for pipeline). SOS are familiar with term "Lamp Off"

Wait for your SOS to make sure the telescope is ready.

Using the DTP:

    • OBJ name = FLAT OFF, OBJ type = FLAT OFF
    • Click automatically save

If you see emission lines in the spectra, then a light has been left on somewhere.

B. FLAT ON: Take flats with the flat lamps on (also required for pipeline).

Kindly ask your SOS to turn on the GCAL lamps on (the ND1 filter should still be in place, and the fold mirror directing the light to the visitor IGRINS port). Quartz lamp.

Using the DTP:

    • OBJ name = FLAT ON, OBJ type = FLAT ON
    • Click automatically save 

How to use IGRINS at the Gemini South Telescope:

1. Telescope Pointing Procedure

A. Ask your SOS to slew to the target (give program ID and target ID).

B. Once on target and the SOS has finished setting up the guiding, take a test image with the SVC (see below).

C. Check that you are pointing to the correct field.

2. Using the SVC

You will break guiding if you move more than 30"

A. Taking an SVC image using the SCV:

    • Set the desired exposure time.
    • Standard practice should be to click "compress" (10% the file size). Otherwise if not compressed, unless absolutely required for your science, please disable the autosave feature on the slit camera viewer. This will save ~30GB of space each night. 
    • Click either "Single" (best for target acquisition) or "Continuous" (if you are guiding, this is good to track what is happening)
    • If you save any images, be sure to record them on your observing log.

B. Using the SCV to move the telescope:

    • On the right side under TCS control, you will see a sort of compass with an empty box in the middle and the cardinal directions as buttons around it. 
    • Enter the distance you would like to move in arcseconds.
    • To move, then click on the button for the direction desired (so E for east, etc.).
    • Dither directions:
      A command to go 50 arcseconds north moves the telescope 50 arcseconds north, and your object will move 50 arcseconds south.
      So, if your target is to the north of the slit, then you need to move north to get it into the slit.
    • Make sure to check any movements by taking an image.

C. Using the SCV to move your target to the reference position:

    • Click on your target in the center image window. A green box should appear on top of it.
    • On the right side under the TCS Control section, click on the "Go R". This will move your object to the reference position, which is the green circle to the west of the slit on the images.
    • Take an image to verify, and you can make corrections using the steps in B to move the telescope.

For further information about the SCV options (such as scaling, Gaussian fitting, etc.) see the "How to Use IGRINS software" page.

3. Using DTP to obtain spectra

A. Move your Target onto the slit

Either use the SCV to nudge your target onto the slit, or begin the process described in the C section below to use the software to put it in the A or B position.

B. Taking H/K spectra:

    • Enter in all observers
    • Enter in the desired exposure time, Fowler Sampling (16 is optimal for science), and repeat number. Note that H and K are synched.
    • Make sure that "Automatically Save" is clicked on.
    • Click the "Start Exposure" button when ready.
    • When all exposures have completed, you should hear the computer voice  "H Finished" then "K Finished"
    • Do not forget to record in the observing log.

      Note: The RA and DEC boxes in the DTP must be populated in order for the frames to be saved. If they are missing you will waste a full exposure time.

C. Nodding or using AB positions:

Nodding will produce better results in data reduction. Using an ABBA pattern is the most common. 

    • Place your object in the reference position using the SCV (see above), then once confirmed, click the "Set Reference Ready To Guide" button in the SCV in the lower right corner.
    • In the DTP in the lower left, click the "Move A" then "Start AB Box". This will move your target to the A position on the slit, and the program will keep track of offsets from the centroid. Any offsets from this point on will be listed in the SCV Status window. Note however that these offsets are not reported to TCS, so you are not guiding without further action.
    • Take any exposures desired in the A position. 
    • When finished, click the "Stop Guiding" button next to the "AB Box" one.
    • To then move to the B position, click on "Move B" then "Start AB Box".
    • Take any exposure desired in the B position.
    • Repeat for whatever nodding pattern that you are using. ABBA is the most common.
    • Note: While keeping your observing logs, track the A or B location of your frames.

Nightly Observing Procedures:

1. Focus

The focus does not need to be changed at GST.

2. Obtaining Spectra for Targets and Standards

The standard procedure for obtaining data with IGRINS should be:

  • Move to the target
  • Take an SVC image and verify that it is your target by comparing to finding charts
  • Take the desired spectra. 

The most common observation will be to obtain an ABBA (or quad) orientation. This means the object is placed on the slit in the A position for the first spectra, then moved to B for a second (then again in reverse). The resulting 4 spectra using this ABBA combination will provide optimal background subtraction for point sources. There are simple scripts available for performing an ABBA observation (see the Additional Options section). Another common observation, particularly for extended sources, will be On-Off. To perform On-Off observations, obtain a spectra with your target on the slit, then another spectra with your target moved entirely off the slit.

  • Move to a nearby A0 star at similar airmass. Similar airmass is the most important thing if there are not many options.
  • Take spectra of the A0 star for calibration. Aim for 1000 counts with a snr of 250.

    Note - if you will be your target observations will last for more than an hour, then you should bracket the observations with an A0 star (get spectra of an A0 both before and after your target observations).

3. Obtain Sky Spectra

You need at least one 300s sky frame each night for the PLP to work correctly. A faint target can be substituted, but if you only observe bright objects then get a sky.

'SKY' is usually the last object of each nights. Telescope setting for SKY requires 5-10 min to be prepared, so we recommend to take SKY in the end of the night slightly after twilight.

SKY Procedure:

  • We use pseudo object named ‘ZENITH SKY’ in OT.
  • Copy object ‘ZENITH SKY’ from IGRINS Calibrations and Tellurics library or daily calibration programs of previous IGRINS nights.
  • Paste ‘ZENITH SKY’ to today’s daily calibration program.
  • RA value of the target in OT should be similar to the current LST.
  • after click Queue, tell SOS that we want this program ID but telescope need to be slewed to the Zenith.

  • Important: when SOS sends telescope to zenith, science fold is automatically parked while we want the fold in. Make sure that science fold is in position before start of exposure.

  • Also check SVC image to avoid any star on the slit.

Additional Options:

1. Looking at your data


files will automatically open in ds9 if you click on them in Finder

data is stored in 'obs_data'

this folder is conveniently found in any Finder window on the top left

2. Changing the PA

The default PA is East-West (90 degrees, which should be included in your target list regardless). To use different PAs, you have to input it into the OT (and should already be in there for most programs). It is best do this before you slew to the target. If you need to change it even after you have slewed to the target, then change the value in the OT, synch, and add to the OT queue. The SOS will then have to slew again to the target. It will be slow to rotate.

4. Guiding

A. Facility Guiding

For almost all observations, we expect to use the facility guiding at Gemini. 

B. Non-facility Guiding

See other IGRINS wiki pages, as this should be highly unusual.

5. Using the ABBA scripts

There are two available scripts to observe an ABBA quad, which will gain the observer time for preparing for their next source, etc.

Simplest (abba_simple_no_guide.script) - no guiding and relying on the tracking, best option to use for relatively bright sources

Simple with guiding (abba_simple.script)  - best option when you also need to use guiding, and is compatible with both on-slit and off-slit guiding.

To use these scripts, in the DTP:

  • Click the "Use Script File".
  • Click "Load" right beneath that, then in the window that pops up, select the "igrins_scripts" folder on the left under favorites. Select which script you would like and open it.
  • Make sure that you enter the desired exposure time, as you would in non-script observing, and that "Automatically Save" is clicked on.
  • When ready, click "Run Observing Mode".
  • You will be prompted to begin the script mode, and if using the script with guiding, you will be prompted each time the target is moved to either A or B.

If you decide you need to cancel (change the name of the file or exposure time or something), it will not run again unless you unclick the "Use Script File" and then click it again.

6. Observing at the Parallactic Angle

This is an advanced mode. 

To observe at the fixed parallactic angle:

  • In the OT, check the chart for the approximate parallactic angle.
  • Be sure to enter that into the OT for the target before you synch it and queue it.
  • You should now working at the fixed parallactic angle.

If you want to double check that you are indeed at the parallactic angle, you can move your target onto A/B then have your TO input a CE offset. Take another SVC image and verify that the target moved in the slit direction.

You are free to observe as usual, nodding in ABs etc.

7. Saving data

We are working on a best method for distributing data to observers. Do not concern yourself with this.

All IGRINS FITS files are 16.8MB. The average file size of a 1 night run is ~32GB, but this varies depending on your choice to automatically save all the SVC files. The spectroscopic files require ~5GB of disk space each night.

Eventually, the data will be available in the Gemini archive.

End of Night:

1. Close the IG Proxy, then the DSC screen sharing.

2. Close the QLP, SVC, DPT, HPK, and the IGRINS Hub windows (and anything else that is opened other than terminal windows).

3. If it is the morning of Mon-Fri (and not a holiday), then please restart the ICC as a preventative measure. Wait a few minutes, and re-open the screen sharing.

if it does not restart, contact Greg, Hwi, and ask the Gemini observer to leave a note that you need someone to turn

otherwise, perform the following:

  •  On the HKP gui, make sure that the “periodic monitoring” (which will say "pause" if it is already selected) and, below that, the “Send Alert (T>20)” buttons stay in effect and that this package stays open and running
  • Mount the detector computers (follow description in start up)
  • Upload the temperatures to the web with firebase (follow description in start up)

4. Close the ICC screen sharing. You are done!

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