This is a summary of normal IGRINS use for observers at the McDonald 2.7m telescope 

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1. Check and zero the telescope pointing

   1. If TCS has not been reset since the prior night of observing, your pointing will be easier to find than if TCS was reset during the day.

   2. Follow either of the directions outlined here:

      1. How to zero the telescope pointing in TCS

      2. Telescope Pointing Procedure

   3. Note: Since IGRINS has returned to McDonald Observatory in late 2024 the pointing has been difficult to obtain because the zeroes are often far off when TCS is reset. Be prepared to spend several hours in the beginning of the night pointing (particularly spiraling around using the paddle in the DTP), especially if you are not an experienced user of McDonald HJST. Our advice to make pointing easier is to pick a star near zenith that has several surrounding bright stars (see example 29 Peg) because if the telescope is very far off in pointing nearby bright stars clustered by dim stars are easier to identify in the slit view camera images than clusters of all dim stars. Remember to take into account the slit rotation when looking at finder charts!

2. Check telescope focus [Note: need to outline this procedure--20241204]
   

   1. Use the hand paddle to adjust the telescope focus

   2. Make sure there is a star near the center of the SVC field of view that is bright enough to measure the FWHM of its PSF but not so bright it saturates the detector

   3. It might be useful to set up a spreadsheet to record your focus values VS. star PSF FWHM

   4. Select minimum and maximum range of focus values to check [Note: need to add a reasonable range of values], start at the lowest range

   5. Start at the minimum and loop through the following procedure (there is hysteresis in the system so we always step through the same way)

      1. Step up in values of 100-200

      2. Take a slit view camera image

      3. Click the star to measure its FWHM

      4. Keep an eye on the shape of the star’s PSF and make sure it looks reasonable

      5. Write down a table with the focus value the FWHM of the star

      6. Repeat the above steps, filling up your table, until you reach the maximum focus value to check or you are confident you are out of focus

   6. Find the focus value that gives the best FWHM (it might be useful to plot your table in a spreadsheet)

   7. Go back to the minimum value in your chosen range

   8. Slowly in small steps raise your focus value until your reach the value that gave you the best FWHM

   9. Take another exposure of your star and double check you get the expected FWHM

   10. If you are confident the PSF FWHM is good, you are now in focus!

   11. Note: If there are large changes in temperature over the night and/or you notice stellar PSFs in your SVC images look bad, you might want to refocus
       

Setting Up Guiding

On Slit Guiding

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1. Move the telescope to Zenith

   1. Using the TCS select Next → Zenith and click yes on all of the pop-up windows

2. Close the IGRINS window cover

   1. Rotate IGRINS back to a PA of 90 degrees, if needed

   2. Raise the east platform using the yellow hand paddle

   3. Close the IGRINS window cover using the handle

   4. Be sure to secure the handle using the velcro strip

3. Stow the telescope

   1. Using the TCS select Next → Stow and click yes on all of the pop-up windowson all of the pop-up windows

   2. Press and hold the button on the dome floor console to move the telescope to the stow position

4. Close the Mirror Window Cover

   1. Using the button on the Colossus Console (the console in the dome with all the red buttons). You should hear the motor stop when it is fully closed.

5. Close the dome

   1. Using the button on the Colossus Console. There will be a loud sound when it finishes closing.

6. Put any wind screens that are over the dome slit back to their stow positions using the handpaddle

7. Park the dome

   1. Using the TCS select Tools → Park Dome and click yes on all of the pop-up windows

8. Close the dome doors

9. Close the dome vents

   1. Using the control panel on the East side of the dome near the door

10. E-stop the telescope

    1. Using the button on the Colossus Console

11. Turn on the passage lights (only once dome is closed fully)

    1. Using the button on the Colossus Console

12. From the control room

    1. Log-out of ATLAS

       1. Click the power button on top right hand side of the lower monitor

13. Turn off the heater in the observing room

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