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1. Darks

Check all the lights are off around the telescope.

Setup:

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

Using the DTP, take darks:

2. Flats

Ask your SOS to:

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※ 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.

Setup:

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

Using the DTP, take darks:

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.

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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:

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:

How to use IGRINS at the DCT:

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:

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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:

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

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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.

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3. Obtain Sky Spectra

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• .

Additional Options:

1. Looking at your data

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

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