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Heterodyne Observing Pool

Contents

Heterodyne Observing Pool
Observing templates
1. Templates for project startup:
2. Templates for observing with EMIR:
Decommissioned heterodyne instruments

Database

The status and a description of all projects participating in the Heterodyne pool can be found in the pool data base.

Pool weeks and observers

Notes on observing

Please use the pool database at https://pools.iram.es to manage the Heterodyne pool projects during observations (login information may be obtained from the AoD or the pool manager). In the pool database, please select the current semester and an observation queue (E330, HERA/E230, Backup; see FAQ for a detailed description) to get a list of the projects. The project status can be one of the following:

SCHEDULED (green) - a project authorized for observing
CONTINUE (yellow) - a project is started and still needs more observing time
ON HOLD (orange) - do not observe this project
DONE (red) - the project is finished, do not continue

For each project, the priority is indicated (with 6 being the highest and 1 lowest). Clicking on an individual project in the list will display a summary for this project, furthermore, you will find the tab logsheets with a list of the observed scans and the possibility to add comments. The visibility of the sources can be checked by looking at the visibility plot (use corresponding button in the menu of the project list), either for all sources of a queue or sources of a single project.

Each Heterodyne pool project has its own subdirectory within the pool account (e.g. ~/142-18), in which the pako procedures are located together with a README file describing how the procedures are used, and which weather conditions are needed.
Please observe all projects for the Heterodyne pool under the pool account poolw-23. To begin the observations, login to mrt-lx1 and start a Pako session by typing gopako, pakodisplay, and pako. Each project should have a script for its general setup, e.g.

@~/142-18/setup

Please make sure that the project number is correctly set (the only way to distinguish the Heterodyne pool projects later), and that the doSubmit parameter is set to YES. Then follow the step-by-step instruction of the project's README to carry out the observation.

The results of the online data processing (i.e. the calibrated .30m files) will be written to the individual project account into the folder:

/vis/142-18/observationData/mrtcal/

One file per backend and per day is created. (Spectroscopic data prior to 2017 February 14th was calibrated with the former calibration software MIRA and stored under /vis/142-18/observationData/mira/).

The uncalibrated data (imbfits files) remain in the pool account:

/vis/pools-22/observationData/imbfits/

If the weather is uncertain and you want to check the conditions without attributing the observing time to a given project, please type in pako

set project test

If it is necessary or you prefer to reduce the data yourself with MRTCAL, you can do so logging onto mrt-lx3 and starting the package with mrtcal. Documentation and a quickstart tutorial for MRTCAL are available on the GILDAS page (see sections Documentation and Tutorials).

For the time being, continuum data (e.g. pointing, focus measurements) are processed by MIRA. If you would like to reduce data yourself with MIRA, please log onto mrt-lx3 and start the package with

cd ~/mira
mira

If you are not familiar with MIRA, please consult the documentation (there is a cookbook section). Some useful commands are:
Load and list the scans of the current day:

file in "../observationData/imbfits"
ftd

Calibrate and display results of a pointing scan:

scan c
scan p
cal all
solve 1

etc., where p is the number of the pointing scan, c the number of the preceding calibration scan, and solve 1, solve 2, etc. retrieves the pointing solutions for the individual bands and polarizations. To obtain the focus corrections, replace p with the scan number of the focus scan. Typing let dopause yes will pause after the subscan results.

FAQ

What is the Heterodyne pool?
- The Heterodyne pool is an observing system used at the 30m telescope to optimize the observing time with the heterodyne receiver EMIR (previously HERA). The projects included into the pool are observed in a flexible way during several weeks in autumn (summer pool), or in winter (winter pool). The Heterodyne pool projects are grouped into three queues depending on the weather conditions required for observation:
  - Excellent weather: projects at high frequencies (typically using the E330 receiver) or observations requiring very good conditions, e.g. observations of H₂O. This list is observed when the amount of precipitable water vapor in the atmosphere is low (pwv<2mm, corresponding to atmospheric opacity tau_(225GHz)<0.12) and the pointing stability is very good (differences between two consecutive pointings below 2").
  - Good weather: projects at 1mm, typically using HERA or E230. This list is observed when the amount of water vapor in the atmosphere varies between 2 and 5mm (0.12<tau₍₂₂₅₎<0.3), or if it is below 2mm, but the pointing accuracy is not very good (due to e.g. strong wind, anomalous refraction).
  - Average (backup) weather: projects at low frequency (3mm, mainly using E090). This list is observed when the amount of water vapor is above 5mm (tau₍₂₂₅₎>0.3).
  During a Heterodyne pool week, the astronomers coming to the telescope observe projects from the three queues depending on the weather. This observing mode improves the chances to observe a project, and not to loose time due to bad weather, as it occurs when the projects are observed within fixed blocks.
How is it decided which project is observed?
- There are three criteria that are taken into account to decide which project is to be observed:
- The first one is the weather at the moment of performing the observations. The weather rules mentioned above have to be respected; depending on the amount of water vapour (which can be checked at any time with the taumeter) it is decided which of the three queues is going to be observed.
- The second one is the priority given by the program committee and the LST of the project. Within the pool data base, the visibility plot displays the visibility of every source of every project ordered by priority (6 = highest, 1 = lowest). The project observed will be the one of highest priority whose source is visible at the moment of the observation.
- Finally, in case that some projects with the SAME PRIORITY and same visibility are visible, priority is given to the one whose observer is at the telescope. In case of doubt, the AoD will decide which project to observe.
Who does observe the projects?
- Observers from the projects included in the pool observe for their own projects as well as for other projects (following the criteria mentioned above). The observers of A-rated projects are expected to come to the telescope (except for small projects < 10h). For big A projects (> 40 hours), two or more observers may be needed. Observers of B-rated projects are also invited to come, they can improve their chance to get data: we will make an effort that observers of B-rated projects coming to the telescope can observe at least a couple of hours on their projects. We need 3 to 4 observers per week, who will observe during the whole week in shifts of 6 to 8 hours each.
How are the projects observed?
- All the projects are observed within the same account, called pools-24. You can access via: ssh -XY pools-24@mrt-enter.iram.es
  In that account, there is one subdirectory per project. Each one of these folders (named xxx-yy, as the name given by the PC to your proposal) contains the following data:
  - the procedures necessary to observe the project
  - A README file explaining STEP-BY-STEP the things that have to be done to properly observe the project. Please, take into account that this README file should be as clear as possible. You do not know who is going to observe your project. If you want to detect one line, specify the rms or the S/N. A typical README file is sent to the PIs. Please follow that schema as much as possible.
  - Possibly a LOG file where the observers explain how the observations have been performed, if they have had any problem, and the decisions that they have taken while observing your data (if the comments were not added to the logsheet in the pool data base).
How can I control the status of my project / manage projects during observations?
- In the pool data base you can check at every time if your project has been observed, the time left, where you can read the comments of the observers, ...: Once you are logged into the database (use the login of your project account to check the status of your project; for managing the projects during observations the pool manager/AoD will give you login information), select your observing queue (BACKUP, HERA/E230, E330) and you will see all the projects within that queue. You can see the number of the project, the name, the PI, the allocated time, the used time*... In the top of the page there is a button called "Visibility plot", where you can display the visibilities of all the sources of the projects. If you click on the number of a project, you will access to the project page, where you have the specific information about the project, the proposal, the PI email address, the logsheets, the visibility plot for that project ONLY... Observers of the heterodyne pool are invited to "play" with this page in order to get familiar with it.
- *Note that the used time (Obs.Time) is the sum of the scan times and that is not including all the overheads.
How do I know if my project has been observed ?
- The AoD at the telescope will send you an email every time your project is observed. In addition, you will find the header information of observations taken for your project in the Tapas data base (login is the same as that of your project account, go to My Projects and Logsheet), or you can check the status of your project in the pool data base (access with your project account login).
How can I check my data?
- Each project has its own account called as their project number (xxx-yy). You can access via:
  ssh -X xxx-yy@mrt-enter.iram.es
  
  The online data processing of the 30m telescope will generate a calibrated .30m file with your data in the directory ~/observationData/mrtcal (one file per backend and day), which you can check e.g. using CLASS. (Note: spectroscopic data prior to February 2017 is located under ~/observationData/mira)
  For taking home/downloading your data, please follow the guidelines in How to transport observation data. If you want to copy data via Internet, please note that our current bandwidth is limited to 100Mbits/s; so please use a program like rsync that allows to limit the transfer speed (e.g. rsync --bwlimit 1000 to 1MByte/s). If you need to transport large amounts of data or have more questions, please contact us.
  More information on data storage, project accounts, archive, etc. may be found in the NCS User Guide (IRAM internal).
Can I change my observing strategy or requirements during the pool?
- YES, OF COURSE! Every time that your project is observed, you will be asked to check your data (see point 7). If you want to modify your strategy taking into account your remaining time, etc... you have only to update your README file in the pools-24 account (check point 4).
Do I have to enter my observing procedures in the Heterodyne pool account?
- No. You have to create your own procedures and your README file, and send them to the pool manager, Brisa Mancillas (mancillas@iram.es), who will check them, and will include them in the pools-24 account. She will let you know if there is something wrong.
What do I do to get the passwords to the heterodyne pool and the project (xxx-yy) accounts?
- For security reasons, we cannot send this information via Internet. If you want to know the passwords, please, contact the pool manager, or phone to the telescope (00 34 958 48 20 02) and ask it to the operator or the AoD.
Who pays the trip and the stay at the telescope of the pool astronomers?
- For astronomers from the IRAM member states France, Germany, and Spain, the expenses for travel and subsistence will be paid by IRAM according to the usual funding rules. Astronomers from other countries will have to pay for their flights, but subsistence and lodging at the telescope are paid by IRAM (as well as a room in IRAM's downtown residencia, depending on your flight schedule).
Who can help me to prepare my procedures?
- If you have problems with preparing the procedures, or if you have any other doubt concerning the Heterodyne pool, please, contact the Heterodyne pool manager, Brisa Mancillas (mancillas@iram.es).

Checklist for project start

* Check the calibrations for each receiver/backend combination, and for each pixel (in case of HERA) on ODP screen.

* Check that CLASS files are correctly written (into /vis/xxx-yy/observationData/mrtcal/*.30m).

* When you start the execution of an observing procedure provided by a pool PI, make sure that you are on the right source (we recommend to select the source in the script, but this is not always done if several sources are to be observed with the same script).

* If you need the wobbler, ask the operator to switch it on. When a wobbler switch observation starts, please check the wobbler signal on the wobbler monitor mounted below the ceiling, in front of you.

* If you use frequency switching, have a look at the oscilloscope to the left of the operator's desk. The LO signal needs to jump with the same phase time entered into PaKo.

A few caveats

* Try to reach the receiver temperatures published in the HERA manual (Figure 2, page 5), at http://www.iram.es/IRAMES/otherDocuments/manuals/index.html. As an indication: at 230.5~GHz, the receiver temperatures of the HERA1 pixels
are typically between 100 and 150 K, and for HERA2 between 150 and 200 K, respectively. For some pixels this will not be possible.

* The HERA derotator may run into its limits during a project, due to the parallactic rotation and its corresponding tracking in the receiver cabin. Once you obtain the first scan XXX of the source to be mapped (typically a calibration), please use MIRA and type

scan XXX
view /derotator [positionAngle]

where positionAngle is the HERA position angle on the sky (typically 9.5 degree for the oversampled mode, and 18.5 degree for the undersampled mode). If you do not specify it, its value is taken from the scan header. If part of
the curve shown is red, you will have to change the HERA position angle to its value +- 90 degree. The time at which you will have to do this is shown on the plot.

* After a telescope slew of 50 degree and more in Azimuth, please do the pointing twice. Even if the first one looks good, the pointing parameters may change meanwhile due to the update of the inclinometer values.

Observing templates

If you use the new control system for the first time and/or need more detailed information, please consult the PAKO manual (cookbook recipes in chapters 3 and 4).

Templates for project startup:

README template file for your observing instructions

Setup.pako general parameters and defines catalogues

Sourcecat.sou a template source catalogue

Templates for observing with EMIR:

EmirLinecat.lin A template line catalogue for EMIR.

emirReceiver.pako Sets up EMIR.

emirBackend.pako Defines backends and connects them to the receivers.

emirPointing.pako Connects the continuum backends, does a pointing (beam switch, calibration optional), and reconnects the spectrometers.

emirFocus.pako Connects the continuum backends, does a focus, and reconnects the spectrometers.

emirOnOff.pako Observing mode: on-off. Switch mode: total power. Is usually called position switch.

emirWobbler.pako Observing mode: on-off. Switch mode: wobbler.

emirFrequSwitch.pako Observing mode: track. Switch mode: frequency switching.

emirOnTheFly.pako Observing mode: on-the-fly. Switch mode: total power.

emirOnTheFlyFrequSwitch.pako Observing mode: on-the-fly. Switch mode: frequency switching.

Decommissioned heterodyne instruments

Templates for observing with HERA

(this page is maintained by Brisa Mancillas and Carsten Kramer)