NEWFIRM Manual

Here we describe the NEWFIRM observing GUI and discuss other information relevant for observing.

• Startup
  • NEWFIRM Observing GUI
  • NEWFIRM IRAF Interface
• Daytime Calibrations
  • Dome Flats
  • Darks
• Telescope Pointing
• Telescope Focus
• Observing
• Shutdown

Startup:

NEWFIRM Observing GUI

• Open VNC viewers [NEWFIRM Obs and NEWFIRM IRAF and NEWFIRM NICC (optional)]
  • The NEWFIRM support scientist of Telescope Operations support staff will help
• Start NEWFIRM GUI in Obs VNC viewer

• Press "Start of Night"
  • This should open the environmental cover.

• Check that environmental cover is open on the NEWFIRM NICC vncviewer.  At present the environmental cover sensor is not working so the NEWFIRM Observing GUI always has the status "Closed".

• Turn on the detector power

• Open the filter tool

• Initialize the filters and close when done

• Check that the current filter position is set to "DARK".  Move filter position to "DARK" if the dark filter is not in position.

• Set Proposal ID (PropID)
  • This will load the proposal PI and co-Is
  • No images can be taken unless the PropID is set to a valid PropID

• Take a junk image to reset image counter/number
  • The image counter does not reset to 1 at the beginning of the night
  • Make sure dark filter is in place
  • Under Exposure Control:
    • Set Basename to "ajunk_"
    • Set Title to "Junk"
    • Set Exp. Time to "2.000"
    • Set Repeats to "0"
    • Set Coadds to "1"
    • Set Fowler to "1"
    • Set Sequence to "1"; This must be the last step.
    • Click "Expose"
    • The image counter will now be reset and calibration data will start with image number *0002*

NEWFIRM IRAF Interface

• Open NEWFIRM IRAF VNC viewer

• Start IRAF window by clicking on the IRAF icon and click open

• The IRAF terminal should now be on your screen.

• Open the IRAF ds9 window

• The ds9 window should now be on the screen.

• Change directory to the current data directory:
  "cd /data/UTYYYYMMDD"

• Start the IRAF mscred and nf packages in the IRAF ecl window.

Daytime Calibrations

Dome Flats

• Change the filter from "DARK" to filter of the first flat to take.  In general, this is "JX".
• Select the filter from the menu and click the "FILTER MOVE" button.

• After completion, the "JX" filter will be in position.

• Open the "FLATS" tool

• This opens the "Flats" dialog box where predefined scripts to take the flats exist.  Pre-existing scripts to obtain a sequence of flats can be found by clicking the folder icon.

• Choose the flat script you want to run and click "OK".

• Click "Load" to load the script and "GO" to execute the script.

• Press "QUIT" when the dome flat sequence is complete.

Additional Details for Observers

The configuration files to take flats are located in the directory "/home/newfirm/flats/" and should serve most purposes.  Custom flat configuration files can be made.  As is customary for NIR observations, flats are taken with the dome lamps turned "On" and "Off".    The default configuration file takes flats for the following filters: JX, HX, KXs, 1644, 2124, and 2168.  The currently used values for the exposure times and lamp intensities are given in a table below.  The format of the configuration of a sequence for the JX filter is:

[1]
title="Dflat J On"
exptime=15.000
nimages=11
fowler=1
coadds=1
filter="JX"
lamp="QUARTZ"
intensity=100.000000

[2]
title="Dflat J Off"
exptime=15.000
nimages=11
fowler=1
coadds=1
filter="JX"
lamp="QUARTZ"
intensity=0.000000

The "exptime" parameter determines the exposure time of the image. The "nimages" parameter controls how many images are taken.  The "filter" parameter selects the filter and the "intensity" parameter sets the dome lamp intensity.  The permitted filter names are in the table below.  The number of "fowler" samples and "coadds" should be "1".  The custom configuration file can be uploaded and used to take flats as described above.  It is not recommended taking flats directly using the GUI.

Flat Name	Exposure Time (s)	Lamp Intensity (%)	Expected Counts (DN)
JX	15	100	~5600
JX	15	0	~750
HX	3	100	~6900
HX	3	0	~200
KXs	2	100	~6300
KXs	2	0	~3000
J1	10	100	~6300
J1	10	0	~450
1066	480	100	~4900
1066	480	0	~10
1187	240	100	~4400
1187	240	0	~150
1644	45	100	~6300
1644	45	0	~50
2096	30	100	~4900
2096	30	0	~1200
2124	20	100	~4100
2124	20	0	~1600
2168	20	100	~4400
2168	20	0	~2200

Darks

• Change the filter to "DARK" by selecting the DARK filter in the menu and click "FILTER MOVE".  Wait until the DARK filter is in position.

• Open the "DARKS" tool.

• This opens the DARKS dialog box where you can choose the dark script to run.  Pre-existing scripts to obtain a sequence of darks can be found by clicking the folder icon.

• Choose the dark script you want to run and click "OK".

• Click "Load" button to load the script and "GO" to execute the script.

• Press "QUIT" when the dark sequence is complete.

Additional Details for Observers

The configuration files that take the dark exposures are located in the directory "/homenewfirm/darks/".  The darks need to be taken in the same observing configuration as the science observations of the night, i.e., matching the exposure time, number of coadds, and fowler samples.  The format of a darks configuration file is:

[1]
title="Dark 001s01c01f"
exptime=1.000
nimages=5
fowler=1
coadds=1

for a dark with an exposure time of 1 second, a Fowler sample of 1, and 1 coadd.

[2]
title="Dark 180s02c08f"
exptime=180.000
nimages=5
fowler=8
coadds=2

for a dark with exposure time of 180 seconds, a Fowler sample of 8, and 2 coadds.  The dark configuration file for observations can be loaded and executed by following the procedure described above.  It is not recommended taking darks directly using the GUI.

Telescope Pointing

At the beginning of the night, the first task is to check the telescope pointing.  This procedure is detailed below.

• Move to a bright star (6th-8th mag)
• Put the JX filter in place by selecting the JX filter from the list and press the "FILTER MOVE" button.

• Use the GUI interface under "Exposure Control" to take an image of the field with the following values:
  • Filter = JX
  • Exp Time = 2 s
  • Repeats = 0
  • Coadds = 1
  • Fowler = 1
  • ObsType = "object"
  • Filename = "zp_"
  • Title = "Telescope Pointing"

• Take an exposure by pressing the "EXPOSE" button.

• Use the IRAF window to display detector 3.  If the pointing is close, the bright star will be located in the detector gap. To display in IRAF:
  nf> display zp_0156[3] 1 zs+

• To place the bright star on a detector (detector 3 to be exact), use the NEWFIRM GUI to perform an offset of 60" N and 60" E.  Enter the offset values in "System Control" panel and press the "TCS OFFSET" button to move the telescope.  North/East offsets have a positive (+) sign and South/West offsets have a negative (-) sign. Take an exposure once the offset is complete.

• Use IRAF to display the new image for detector 3.
  nf> displ zp_0157[3] 1 zs+

• Use the IRAF nf.zp task to calculate the offset of the star to the center of the detector gap.  The "zp" task is a wrapper to the "imexam" task.  Follow the on-screen instructions to determine the offset.  The "zp" task can only calculate the offset if the star is in detector 3.

• Use the NEWFIRM GUI to perform an offset of 60.3" S and 96.3" W.  Enter the offset values in "System Control" panel and press the "TCS OFFSET" button to move the telescope.  North/East offsets have a positive (+) sign and South/West offsets have a negative (-) sign. Make sure to include the minus sign for these South/West offsets.  When the offset is completed, ask the Telescope Operators to perform a telescope zero-point.  Take a new image after the Operators have completed the Telescope Zero-Point.

• Check the quality of the telescope pointing of the last image by loading the image into a ds9 window.
  • Open the FITS File as a "Mosaic IRAF" image.
  • Select the file, e.g. "/data/UT20250513/zp_0158.fits". Make sure the path is for the current data directory.
  • Change the image scaling from "Min Max" to "ZScale" in the ds9 "Scale" menu so you can see the stars.
  • Open the Analysis/Catalogs/Infrared/2MASS Point Sources catalog in ds9.
  • Create a source filter in the 2MASS Point Sources window, e.g. "$Jmag < 13" (or 12 or 14) and press "Filter" to display stars in the 2MASS Catalog with a J magnitude less than 13 mag (or 12 or 14 mag).  The filter magnitude can be changed as necessary.
  • You will see the 2MASS Point Sources overlaid on the mosaicked ds9 image.

• The Telescope Pointing is now complete.

Telescope Focus

• The Telescope Focus is performed at the beginning of the night after the Telescope Pointing check is complete.  It is normally done on the same field as the Telescope Pointing. 
• The Telescope Focus depends upon the ambient temperature and the selected filter.  All focus exposures should be taken using the JX filter.
• Since re-commissioning NEWFIRM, we have maintained a spreadsheet on a shared Google Drive where the best focus in JX and temperature are recorded.  That spreadsheet can be found here.
• Before running a focus sequence it is suggested to change the telescope focus manually to the best focus value predicted by the spreadsheet for the current temperature.
  • Set filter to JX.  It should already be JX after the Telescope Pointing procedure.
  • Check the temperature.
  • Use the spreadsheet to predict the best focus for that temperature.  Enter the temperature in the cyan box below "Temp".
  • Set the focus in the NEWFIRM GUI.  The NEWFIRM focus tool only performs relative offsets from the current focus.  Calculate the focus offset (Offset = Desired Focus - Current Focus) and enter the value in the box below "TCS FOCUS".  Press the "TCS FOCUS" button when done and you should see the current focus change.
  • Take an image.
    • Filter = JX
    • Exp Time = 2 s
    • Repeats = 0
    • Coadds = 1
    • Fowler = 1
    • ObsType = "object"
    • Filename = "focus_"
    • Title = "Focus Test"
  • DIsplay the image in IRAF and inspect the image in IRAF with imexam. Pressing the "e" key in imexam with display a contour plot.  If the image is close to focus, the contours will appear round.
    nf> displ focus_0159[3] 1 zs+
    nf> imexam
• Take a focus sequence.  Even if the focus looks good from the previous step, taking a focus sequence records the current temperature value into a database that can be rad by the observing GUI and will alert the observer to temperature changes that require a focus offset.
  • Set the observing parameters for the sequence (JX filter, 2 sec exposure time, 0 repeats, 1 coadd, 1 fowler) in the "Exposure Control" panel.
  • Select the "nf_focus_wide" script in the "scripts" menu.
  • Enter the expected focus value in the "args" box.
  • Press "exec".
  • This script will take nine focus images centered on the input expected focus value.
• Determine the best focus using the NEWFIRM IRAF "nffocus" task.
  • The "nffocus" task is a wrapper to the IRAF noao.obsutil.starfocus task.  It cannot use the Multi-Extension FITS (MEF) files that the NEWFIRM control software writes to disk.  It can only work on one detector.
  • The NEWFIRM "nf_focus_wide" (and "nf_focus_narrow") task writes a list of the files taken during a focus sequence.  This file is "/tmp/focuslist"
  • Edit the file "/tmp/focuslist" so the "nffocus" task will only work on one detector.  This is done by appending "[n]" to the end of the file names where n=1,2,3, or 4, corresponding to detector 1, detector 2, detector 3 or detector 4. The text editors available are: vi, gedit, and nano.
    • Before editing, the entries in the file look like:
      /data/UT20250513/focus_0174.fits
      /data/UT20250513/focus_0175.fits
      /data/UT20250513/focus_0176.fits
      /data/UT20250513/focus_0177.fits
      /data/UT20250513/focus_0178.fits
      /data/UT20250513/focus_0179.fits
      /data/UT20250513/focus_0180.fits
      /data/UT20250513/focus_0181.fits
      /data/UT20250513/focus_0182.fits
    • After editing, the entries in the file should look like the following to select detector 3:
      /data/UT20250513/focus_0174.fits[3]
      /data/UT20250513/focus_0175.fits[3]
      /data/UT20250513/focus_0176.fits[3]
      /data/UT20250513/focus_0177.fits[3]
      /data/UT20250513/focus_0178.fits[3]
      /data/UT20250513/focus_0179.fits[3]
      /data/UT20250513/focus_0180.fits[3]
      /data/UT20250513/focus_0181.fits[3]
      /data/UT20250513/focus_0182.fits[3]
  • Execute the IRAF "nffocus" task.
    nf> nffocus
  • The "nffocus" task will automatically display the first image of the focus sequence.  The task will then prompt the observer with the following:
    ** Select stars to measure with 'm' and finish with 'q'.
    ** Additional options are '?', 'g', and :show.
  • Select a star and press "m".  A graph showing a plot of FWHM vs Focus and Ellipticity vs Focus will appear in the irafterm window.
  • After pressing "q", the "nffocus" task will quit and display the results in the IRAF ecl window.
  • Set the telescope focus to the value determined by the "nffocus" task.  Calculate the offset between the desired focus and the current focus (Offset = Desired - Current) and enter the value in the box below "TCS FOCUS".  Press "TCS FOCUS" to change the focus value.
  • The software will also record the temperature.  During the night it will compare the current temperature to the temperature during the focus sequence and display a warning if the temperature changes enough to affect the focus.
  • The NEWFIRM filters are not parfocal, so the telescope focus needs to be changed when changing filters.  The focus offsets have been determined during engineering time with stable and good (<1.2" FWHM) seeing.  The offset values relative to JX are given here. The NEWFIRM GUI has an "AutoFocus" option that will change the focus when the filters are changed.  Enable the AutoFocus tool by checking the box for "AutoFocus" for filters.
• The Telescope Focus sequence is complete.

Additional Details for Observers

We will discuss how to check image quality using imexam during a focus sequence.

We will discuss how focus differs for observations near zenith with respect to observations at higher airmass.

We will discuss how focus changes with temperature.

The telescope focus offsets, relative to the JX focus, is given below.  The table can also be found here.

FILTER	Focus Offset (relative to JX)
JX	-
HX	+100
KXs	+220
J1	+50
1066	-50
1187	+50
1644	+100
2096	+80
2124	+165
2168	+175

Observing

• Using GUI (not recommended)
• Using GUI scripts
• Using GUI sequences
• Using CLI observations

Shutdown

• Put the "DARK" filter in place.
• Turn off the detector power.
• Close the environmental cover.  Pressing the "End of Night" button should do this.  You can check on the NEWFIRM NICC vncviewer.
• Exit the NEWFIRM GUI.