MUSTANG-2 GUI

This guide shows you how to check your data with the MUSTANG-2 GUI.

Start the m2gui

To open up the m2gui, first make sure you are in a directory that you have write permissions in and then in a terminal execute:

~penarray/Public/startm2idl

Once that version of IDL has started execute m2gui.

After you have opened the m2gui follow these steps to check the tipping scan, monitor the beam shape (width, widthA, widthB) and peak of calibrators (Peak_Height), or to just check the data.

1. Go online

   Click the online button.

   

   Note

   If you want to open up a previous project that is not the current online project, click Browse Projects, find the project+session in the left hand column, and double click that folder to open it up.

Check the Tipping Scan (Skydip)

What is a Skydip (Tipping Scan)?

See this explanation.

1. Select tipping scan

   Under Calibration, click Select Tip Scan and choose the most recent scan number from the bottom labeled Tip under scan type. At the beginning of the night, this should be from scan 1, before the 3 OOF scans (see below image - blue box).

   

2. Inspect plots

   Many plots will pop up - one for each roach showing the results of the tipping scan for each roach. You can click out of these once they finish unless you are particularly curious about specific roaches. After these plots have been produced, you will see a graph to the right in the main gui window, showing the results of the tip scan - each roach is plotted in black with a fit in green. Check to make sure that it looks reasonable.

   

   Example of tipping scans:

   Good Tip Scan

   A good weather skydip. The black lines (one for each roach) should be fairly free of wiggles and the dashed green line (which is the fit) should follow the black lines fairly closely.

   

   Bad Tip Scan

   A bad weather skydip. The black lines (one for each roach) are full of wiggles and the dashed green line (the fit) is not following the black lines well.

   

   If the tipping scan doesn’t look right (a lot of wiggles), try running the skydip script in AstrID. This reruns the tipping scan without having to redo the whole OOF. If it still looks bad, check the weather conditions in CLEO. The weather might not be good enough to observe (consult 4. General Advice for Determining “Bad Weather“ for advice). You can also call one of the M2 instrument team and get their advice.

3. Check the number of live detectors

   At this stage, check the number of live detectors, as well as throughout the night. Record this in your observing log.

   In the image below, you can see where to check the number of live detectors:

   

   Generally it’s good to have 170+ live detectors, however it can sometimes be as low as 160 if the tuning step didn’t go very well. If you see this number as low as the 150s or 140s (especially if it’s lower than that, which it shouldn’t be) be sure to contact a M2 team member. You can also try re-tuning (see section A) and hope that that fixes it.

4. Continue

   If the tipping scan and number of live detectors look good.

Note

You might notice that plots of the skydip can show temperatures down to 0 K and even negative temperatures. Recall that MUSTANG-2 is not a total-power instrument, so we don’t retain knowledge of an absolute level. The mean level is thus arbitrary. For skydips, we plot the first data point as zero. For all other timestreams, we generally set the mean to zero.

Make Calibrator Map

To make a map of a calibrator, after you have run the m2quickDaisy script on a source in AstrID, do the following:

• Click Update Scan List to find the source scan number of the source you just observed

• Set the Scan Numbers to the scan number of interest

• Set Source Type to Calibrator

• Click Make Map

This will open up an image of the daisy map that you selected. The map should look something like this:

What you see at this stage is an image of the daisy scan. In the center is your calibrator source, visible because it is a bright source. Later, when looking at daisy scans of your science source, it’s very likely that you will only see a flat map in the center because it’s so much more faint.

What is a Daisy Map?

See Explanation of M2 scan pattern: Daisy.

Fit Calibrator Map

First, Make Calibrator Map.

Then to fit the map of the calibrator click Fit Map. This action fits a Gaussian to the point source. Because the point source is assumed to fill a single beam, the resulting Gaussian width parameters are taken as the beam parameters.

Fitting the map, will

• produce the following plots in the gui

  

• print out the fitting parameters in the terminal

  

  Note

  The Floating underflow error you see in the output is not a concern.

For tracking the beam, write down the values for PEAK_HEIGHT, WIDTHA, and WIDTHB in the observing log to compare to later pointing scans to monitor the beam and decide if you need to re-OOF.

Note

When you fit a quick daisy map, the units of PEAK_HEIGHT that are output in the terminal are in the units of \(\mathrm{T}_{\mathrm{RJ,FB}}\) (see more details in the GUI Units section above). The units of WIDTH are arcseconds.

Note

Occasionally, one or more detectors may show glitches in their time streams. These faulty detectors appear as artifacts in the maps and can distort the map’s scaling. As a result, the source may appear fainter than it truly is, and this can lead to a poor fit to a point source or even prevent the GUI from fitting the point source altogether. See Use crmask to Mask Bad Detectors on how to mask the bad detector(s).

Make Science Maps

If you would like to make a map of a science scan(s), you can do so by following the same steps as making a map of a calibrator with the following modification

• under Source Type select Faint Science

Note

The Faint Science option is for targets that do not have bright sources in the field (typical M2 science targets). If you have bright sources in your science target, you can use the Science option instead.

Note

You can add several science scans together by putting them all separated by commas in the scan list. Please note that when you put several science scans together to make a map, it will likely take a while (>5 minutes) to make the map. A suggestion to combat this is to have two GUIs open while observing, one for checking the beam and one for making science maps.

Note

You may not see any signal in your science map in the GUI. This is because. To see what your object looks like and what sort of SNR you are getting, you’ll want to look at an SNR map. See instructions on how to do that below.

Make SNR Map

You can make an SNR map with the GUI. To do this, first follow the instructions above for making a science scan, once the map has been made, click the SNR map button.

Make SNR Map

To make an SNR map, first make a make of your science scan(s), then click the SNR map button.

SNR Example

Resulting SNR map from a map of MOO 1142.

Checking Time Streams

It is a good idea to check the time streams (checking how the sky temperature is changing over time) as well as the maps. Time stream is the same as a TOD (time ordered data).

To check the time steams:

• Make your map (see Make Calibrator Map or Make Science Maps)

• Click Show Time Stream button underneath the Fit Map button after making your map

  

Here is what different types of time streams look like:

Calibrator Time Stream

This is an exemplar time stream for a calibrator source. Notice that you see the point-like source as a gaussian peak in most time streams.

Faint Science Time Stream

Faint science time streams (a cluster) in good weather. Notice how nice and flat the time streams are.

Note

There may be detectors that have glitches that are not flagged by the imaging making pipeline used by the GUI. See Use crmask to Mask Bad Detectors on how to mask the bad detector(s).

Use crmask to Mask Bad Detectors

Occasionally, one or more detectors may show glitches in their time streams. These faulty detectors appear as artifacts in the maps and can distort the map’s scaling.

Below is an example of what a map with a bad detector looks like (streaks indicative of a bad detector marked in red):

Identify Bad Detector(s)

To fix this, you need to identify the bad detector(s) then use the crmask option to mask out the bad detectors. To identify the bad detector, you need to inspect the time streams to find which detector is anomalous. To inspect the time streams click the Show Time Stream button. Then look through the time streams on each raoch to find the anomalous time stream(s). The detectors are numbered on the Y axis. In this case the bad detector is on roach 4 detector 38 (in yellow box).

Update crmask

Now do the following to include that anomalous detector in the detector mask (and exclude it from the map):

Note

The crmask indicates the roach number by the “c” (c=column) values and the roach number by the “r” (r=row) values and the indexing for roach values start at 0. So in this example, roach 4 detector 38 would be c3 r38.

Click Set crmask

Find your anomalous detector

The current crmask will pop up. Scroll to roach 4 detector 38 which is c3 r38. Note that this detector is currently selected so included in the map.

Unselect the desired detector

Simply click on the box next to the detector that you want to exclude from the map. This will deselect it and not include it in the map.

Warning

Once you add something to a crmask it will stay included in the mask (in crmask) for future maps.

Note

It is a good practice to note which detectors you masked in your log.

Remake Map

Once you have set the crmask, now you are ready to remake the map. To do so click Make Map. You can see in the image below that the bad detector has been masked and the scaling has changed.

Save FITS image

It is possible to save the images that you make in the GUI as a FITS image. Instructions below:

1. Set image path.

First you need to set the path where your image will be saved. To do this click in the Path box marked in red in the image above.

2. Set image path via popup.

A box will popup where you can set the path and file name. Hit enter to set the path.

3. Save image.

Once you have set the image path, click Save FITS image.

Inspect the Raw Data

When you make a map and look at time streams you are viewing processed data. There are various situations when it is beneficial to look at the raw data. For example, if you see evidence of glitches in the skydip or science timestreams.

For example, let’s say you see the following glitches in your science scan time streams (see features marked with yellow rectangle).

In order to diagnose these glitches you can look at the raw data. To do this, first click the Advanced Features tab (marked with purple box in image below). Then find the Plot Scan box (marked with orange box in image below), type the scan number you want to plot, make sure that the raw option is chosen, then hit enter.

In the above plots the x-axis is time and the y-axis is phase (radians). There are 256 channels in data space - each one corresponds to resonator on a specific roach. The Col is the roach number (again indexing starts at 0 so roach 1 is Col``=0)and ``R is the row number. Purple indicates a detector that has been flagged.

In the image below, you can see the detectors that exhibit a step function in their time streams, which appear as the features observed in the processed time streams after applying the FFT.

You may also see glitches in a skydip, exhibited below.

To view the raw time streams, follow the same process described above; the characteristic glitch is again visible. You can see that many detectors exhibiting this glitch have been flagged (those that have an X through them), though some remain unflagged and are responsible for the spike at approximately 42 degrees elevation in the skydip above.

Weather Info

When you are Online/doing live observations, you can get information about the current weather by pressing the Weather Info button.

Once you press the Weather Info button, you should see a plot with information about the wind and separate a radar plot like the following:

Note

You can produce the radar plot by pressing the Weather Info button only when you are doing live observations. If you are using the GUI for data inspection after the fact, to produce the radar plot you need to do the following commands in the IDL prompt:

summarizeparproj, projsum
preside_weather, projsum, onsky=1

m2gui Troubleshooting

m2gui Hangs

If your m2gui is hanging (won’t quit), you will need to kill it and open a new window. To kill the GUI, do the following in a terminal:

xkill

This will turn your cursor into an x. Use the x to click on the GUI window (xkill allows you to select the window of the process you want to kill). Then close the terminal that m2idl is running in to fully kill everything.

If that doesn’t work for some reason, you can get the PID of the GUI and kill it manually with the following commands in your terminal:

ps -u

Find the PIDs of startm2gui and idl and kill both.

kill -9 PID

m2gui is slow

If m2gui is slow/not working, you can ssh to another computer and start m2idl and the GUI from there.

m2gui is not making maps

When you start the m2gui, you need to be in a directory that you have write access to, otherwise the gui will not make maps. It will display scans but will not make maps. If you have this issue, close the GUI and terminal running m2idl, cd to a directory where you have write permissions and restart m2idl and the GUI.

GUI Units

The GUI makes maps in the units of the selected calibration. By default the calibration is the skydip which is in units of \(\mathrm{T}_{\mathrm{RJ,FB}}\) (see more info here).

If you are curious, there are four map unit options in the GUI:

• \(\mathrm{T}_{\mathrm{RJ,FB}}\) is the forward beam surface brightness temperature under the Rayleigh-Jeans approximation (the units of the skydip) - this is the default value.

• \(\mathrm{T}_{\mathrm{RJ,MB}}\) is the main beam surface brightness temperature under the Rayleigh-Jeans approximation.

• T_CMB is the surface brightness temperature assuming spectral intensity using the Planck function (shape) for T_CMB. See, e.g. Mroczkowski (2019) for a review.

• Jy is Janskys.

Calibration files are required to convert a map from its default units, as they contain the necessary unit conversion information. These files are produced by the MUSTANG-2 team during the calibration process, which takes place in the days to weeks after observations are completed. As a result, unit conversion is not available during live observations.

Once calibration is complete, you can change the units in the GUI. To do this, locate the units section highlighted by the red box in the image below and click on “No Cal Loaded” to load the appropriate calibration file for your desired units.

After loading a calibration file, the available units become selectable, while any units without conversion information are grayed out.

Attention

While unit conversion is possible within the GUI, the MUSTANG-2 team emphasizes that the GUI is intended primarily as a quick-look tool and not as the main interface for working with calibrated data.