Observer Cookbook - DCT 4.3m
This is a summary of normal IGRINS use for observers at DCT
Before You Begin:
Check IGRINS is healthy, verify with your TO.
Observing timelines:
First half of the night:
- 1 hour before sunset: Follow Start of Night, then take calibrations.
- 20 minutes past sunset, your TO will open, do wavefront tests, and perform a nightly pointing check. This should take 20-30 minutes.
- 40 minutes after sunset, your IGRINS on-sky time begins (nightly observing procedures).
- 5 minutes before your time is up, begin the End of Night procedure.
The order of operations should be tests, darks, flat offs, flat ons, opening and TO checks, science.
Second half of the night:
- Begin with Start of Night, then begin your IGRINS on-sky time (nightly observing procedures). You can observe 30 minutes until sunrise.
- 20 minutes after sunrise, your TO will close, during which they will move the telescope to zenith. Then, you will take calibrations (about 1 hour).
- 80 minutes after sunrise, your TO can shut down the telescope.
- Then, follow the End of Night procedure.
The order of operations should be test, science, flat offs, flats ons (this order is necessary to reduce persistence from the flat lamps on the calibrations). Darks are not needed.
Full night:
Follow the first half of the night timeline (calibrations are only needed at the start of the night).
Start of Night:
1. Wake up ICC on the right (a big iMac) and close these windows (HKP, DTP, SCP, QLP, IGRINS Hub) on the Desktop if they happen to be open. HKP and the IGRINS Hub should have been open, make sure to close them now. Do not touch any terminals that have tmp350.py, sh_to web.sh, and test_mnt running, just in case they happen to be visible - these will often be running on a different Desktop window so you do not see them. As such, your work should be be limited to Desktop 1 and 3.
2. Turn on the IG proxy by clicking the icon on the top right corner of the iMac desktop.
3. Turn on the IG software (HKP house keeping package, SCP slitview camera, DTP data taking package) by opening a new terminal and typing:
> cd ~/igrins_admin
>sh run_icshub.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.
4. Check 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”
5. 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.
Calibrations:
The recommended calibrations are listed in the following table, and the procedure below.
Note - if TCS is not running (run by TO), the header information will not be complete. There will be error messages about the missing header information if exposures are saved, but that can be ignored.
*UPDATED SEP 2017 - Use the two 600 W flat lamps turned all the way up. Do not use the LMI lamps because they are likely to fault and give inconsistent flux.
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.
Type | exposure time (s) | number | Number of Fowler Reads |
---|---|---|---|
Dark | 45 | 10 | 16 |
Flat off | 45 | 10 | 16 |
Flat on | 45 | 10 | 16 |
1. Darks
(May be done without a TO.)
Check all the lights are off around the telescope.
Setup:
- dome is closed
- instrument cube is closed
- all lights are off
Note - the telescope has to be at zenith to close the cover.
Using the DTP, take darks:
- OBJ name = DARK, OBJ type = DARK
- Click automatically save to save images
Don't forget to start the observing log.
2. Flats
(TO is required)
Ask your TO to:
- move the telescope to flat position
- open the telescope and instrument cube
- put in the IGRINS fold mirror
- turn on TCS
A. FLAT OFF: Take flat offs before the flat lamps are on (required for pipeline).
Wait for your TO 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 (like the stair well).
B. FLAT ON: Take flats with the flat lamps on (also required for pipeline).
Kindly ask your TO to turn on the IGRINS Flat lamps (all lamps).
Using the DTP:
- OBJ name = FLAT ON, OBJ type = FLAT ON
Click automatically save
How to use IGRINS at the DCT:
1. Telescope Pointing Procedure
A. Define your pointing
Preferred - use a target list as described in the Additional Options section:
Tell your TO that you are using a target list, and they will screen share with the IG computer. Then you will highlight the target entry on your list and click "Send to TCS". Your TO can then move to your target.
Alternatively - you may tell your TO the coordinates of your object, and they will point the telescope accordingly.
B. Once on target, take a test image with the SVC (see below).
C. Check that you are pointing to the correct field.
2. Using the SVC
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
- For on-sky sources, click the "RA/Dec from TCS next" button to populate information. Otherwise, fill it in.
- Enter in the desired exposure time, Fowler Sampling (16 is optimal for science), and repeat number. Note that H and K can be synched.
- Make sure that "Automatically Save" is clicked on.
- Click the "Start Exposure" button when ready.
- When all exposures have completed, you will 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
Begin your night with verifying or finding the focus for the IGRINS instrument.
- Using the Telescope Pointing Procedure, go to a brighter target or A0 star (K mag ~ 5-8).
- Then using the SVC (see section below for how), take a test exposure of the target. If it is positioned near the edge of the field of view, move into into the field and take another test image. There is no need to save those acquisition images.
- Measure the FWHM of the star by clicking on it in the center SVC image window, and a profile should appear in the window above it - for more information on how to use these features in the SCV then read the "How to Use Software" page.
- The default focus for IGRINS is 1140, if you suspect that it is not in focus (especially if the FWHM > 1.5"), then you may want to test different focus values.
- You can politely ask your TO change the focus (steps of 100 or 50 are a good idea) and then take SVC test images at each value, measuring the FWHM. Settle on the focus that provides the smallest FWHM, but don't worry about perfecting it (focus steps of less than 25 are not necessary). Make sure to record the focus that you adopt on the observing log.
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 300s exposures using 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. Get 300s exposures using an ABBA setup.
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. If you will not get one of these for your science, then please get one to help with reductions.
Additional Options:
1. Looking at your data
ds9:
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
Quicklook:
> cd igrins/igrins_admin
>sh run_qlp.sh
This will open two different windows (each H and K). In the K window, click 'OPEN' and go to the 'obs_data' directory (this folder is conveniently found in the window that opens on the top left) and find the K image that you want. Do the same with H.
Checking the "fits" button will enable you to look at a specific image, or alternatively, the "Auto Refresh" button will update with each newly obtained spectra.
Click on the thumbnail image on the right (a yellow box overlay will appear). Adjust the scale, etc. as needed and hit apply, but you must click again on the thumbnail image to update the larger image.
2. Automated digital log sheets
If you prefer digital log sheets instead of the hand writing or want to have it as a backup, automated digital log sheet is available.
> cd igrins/igrins_admin/misc
> sh run_log_uploader.sh yyyymm
You should run log uploader before you take the first exposure. If you want to create sheets for December 2018, you can type 'sh run_log_uploader.sh 201812'. New Safari window will pops up with an empty google sheet. Log will be updated by every new exposure you take. You can add comments or notes to the google sheet. Since these sheets are managed by IGRINS team, please avoid sharing the sheets with your personal account directly. You can download them as file or create a copy when you finish your run.
3. Using a target list
Loading in your target list:
- Target lists need to be in the correct format, see ....[example file]
- Connect to the USB Hub on the IG Mac .
- Upload lists into the directory on the IG machine Desktop/"Observer Target Lists" (you will both upload and find these files here later).
- Open the Observer Target List gui (icon on the right side of the desktop).
- Click on File > "open target list" using the Observer Target List gui. Find the list(s) you want from the above directory.
Pointing to a target on your list:
- Your TO will screen share with the IGRINS machine.
- Highlight your choosen target in the Observer Target List gui.
- click "Send to TCS".
- verify with your TO that they have recieved the correct information and can then slew to your object.
4. Real time field of view
> cd igrins/igrins_admin/misc
> sh run_tcs_next_monitor.sh
Then you can check the FoV at https://igrins-jj.firebaseapp.com/status in the web browser. This page is saved in the Bookmarks/IGRINS/ in the Safari on ICC.
Every time you click "Send to TCS" in target list, this page will refresh. Offset made in SCP is applied in FoV unless you click "Clear Offsets" button in target list.
5. 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 two options:
- Include the desired PA in your target list. Any alternative value can but used.
- Ask the TO to change the PA to the value that you desire.
6. Guiding
A. No Guiding
For exposures less than 300s, guiding is not necessary at the DCT.
B. On-Slit Guiding with Target
When your target is bright and relatively unsaturated in the SVC.
- On the right of the SCV, in the Choose Algorithm box pick "2D Gaussian(M) Fitting" or "Center Balancing".
- Place the target on the reference position by clicking on the target in the center Image Window, and click "Go R" button on the right side.
- Advanced: dAX & dAY, dBX & dBY can be redefined for either AB nodding or On-Off nodding.
- Click "Select A-B & Guide Position" if these were changed.
- Click "Set Reference & Ready to Guide" on the bottom right.
- In the DTP window, select "Move A" and then "Start AB Box".
- Back in the SCV, click the "send AG offsets to TCS" button below the status window - this is the action that actually will make the software apply offsets to get the telescope to move to guide.
- Monitor guiding by taking continuous images and checking them. Your target should stay on the slit!
C. Off-Slit Guiding with Guide Star
- Method 1: Unknown Offset (Target visible but faint) - click and guide.
Off-slit guiding when you see the target and the guide star in a slit camera view but don't know the offsets.
- Choose "2D Gaussian Fitting" as a centroid algorithm.
- Place the target on the reference position by clicking the target in the center Image Window, and click "Go R" button on the right side.
- Advanced: dAX & dAY, dBX & dBY can be redefined for either AB nodding or On-Off nodding
- Click "Select A-B & Guide Position" if these were changed.
- Click the "Use Guide Position" button.
- Click on the guide star in the center Image Window and then the "Sel G" button on the right. Make sure a pink box moved onto the guide star.
- Click the "Set Reference & Ready to Guide" on the bottom right.
- In the DTP window, select "Move A" and "Start Guide Box".
- Back in the SCV, click the "send AG offsets to TCS" button below the status window - this is the action that actually will make the software apply offsets to get the telescope to move to guide.
- Monitor guiding by taking continuous images and checking them. Your target should stay on the slit!
- Method 2: Known Offset in Slit_length (dSL) and Slit_width (dSW)
- Choose "2D Gaussian Fitting" as a centroid algorithm.
- Click "Use Guide Position".
- Enter nod position and guide offsets.
- dAX & dAY, dBX & dBY can be redefined for either AB nodding or On-Off nodding.
- Type dGSL and dGSW values in for guide star.
- Click "Select A-B & Guide Position".
- Take a single exposure on the Slit Camera View (SCV) package
- Click the guide star on the Image Window.
- Click "Go G" button and take a single exposure to see the guide star moved to the pink box.
- Target should now be located on the reference position ("R").
- Click "Set Reference & Ready to Guide".
- In the DTP window select "Move A" and "Start Guide Box"
- Back in the SCV, click the "send AG offsets to TCS" button below the status window - this is the action that actually will make the software apply offsets to get the telescope to move to guide.
- Monitor guiding by taking continuous images and checking them. Your target should stay on the slit!
c. Method 3: Known Offset in Pixels
Off-slit guiding with known offsets in Pixels between a (faint) target and a guide star.
- Choose "2D Gaussian Fitting" as a centroid algorithm.
- Click "Use Guide Position" in DTP.
- Enter nod position and guide offsets.
- dAX & dAY, dBX & dBY can be redefined for either AB nodding or On-Off nodding.
- Type dGX and dGY values in pixels.
- Click "Select A-B & Guide Position".
- Take a single exposure on the Slit Camera View (SCV) package
- Click on the guide star on the center Image Window.
- Click "Go G" button and take a single exposure to see the guide star moved to the pink box.
- Target should now be located back on the reference position ("R").
- Click "Set Reference & Ready to Guide".
- In the DTP window select "Move A" and "Start Guide Box".
- Back in the SCV, click the "send AG offsets to TCS" button below the status window - this is the action that actually will make the software apply offsets to get the telescope to move to guide.
- Monitor guiding by taking continuous images and checking them. Your target should stay on the slit!
Note that the annular guiding (DCT Guiding system) is currently not an option with IGRINS due to the focus required for IGRINS.
7. 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.
8. Observing at the Parallactic Angle
This is an advanced mode.
To observe at the fixed parallactic angle:
- Have the TO set the PA to 180 (it might be possible in your target list as well) and move to the target.
- While it is moving, have the TO turn off the rotator.
- On the SCV, uncheck the "Rotator(manual)" box and then manually enter in the parallactic angle. The parallactic angle for the current pointing is shown in the Proxy.
- You are 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.
9. Saving your data
We are working on a best method for distributing data to observers.
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.
If you are at the DCT for the observing run, then we recommend you save your files on your own storage device. You can easily connect to the IGRINS Mac and copy your files with a USB connection using the USB Hub (do not delete them after copying to your own device).
End of Night:
1. Click on the nightly report icon on the desktop, and fill out the night report.
2. 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
3. Close the SVC and DPT windows. You should see the status change in the IGRINS Hub to "disconnected"
4. Close the IG Proxy and the Observer Target List App.
Do not log out of the IG computer, it will go to sleep on its own accord
Please place the "Please do not touch" sign in front of the Mac
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