Quick Guide for Dummies - The novice 30m observer

This guide is meant to help the novice observer at the 30m telescope getting started.

Howto observe ?

Well before your observations are scheduled to start, it is a good idea to prepare observing scripts, i.e. small PaKo routines, to setup the receivers and spectrometers, to select your sources and lines, etc.. The Astronomer-of-Duty is there to help you doing this. Script should reside on the subdirectory ~/pako of your project account.

When time has come to start real observing, take a seat and let the Astronomer-of-Duty and the Operator guide you through the first steps. It is really easy. You'll need to log into your project account onto mrt-lx1 and start the observing software called PaKo, run the receiver and backend setup scripts, select a source, and then e.g. start a pointing. This will send the commanded frequencies to the synthesizers, and it is now on the operator to "tune" the receivers, to make them ready for observations to start. This may take 10 minutes or more. Once tuning is finished, you may want to check the pointing and focus of the telescope first, before going to your science source. See below.

Getting started

1. Log into your project account at the PC on the observers desk
2. Start a new X-window/ KDE session under your project account
3. Click on icon "paKo". this will connect to your project account on mrt-lx1

4. In the X-window, type: goPako, pakoDisplay, pako

5. Run your setup scripts a the pako prompt, e.g. @ setup

6. And then continue with set doSubmit yes, start

A typical observing session: PaKo

Displays

Computer System

What are all the screens for ? Network topology or entering the unknown

mrt-lx1 is the name of the workstation to run the observations. This is the central machine, the observer is using for running PaKo. The online data processing software Odp is running on mrt-lx3. During observations it is continuously transferring IMBfits raw data from mrt-lx1 to mrt-lx3. The observer should use mrt-lx3 (or mrt-lx2) for offline data processing.

My machine is called mrt-lx18. Now what ? Software

PCs with numbers larger than 4, are small PCs used as terminals. Not much software is installed on these PCs and the user may want to quickly change to one of the main workstations described above, e.g. via ssh -X mrt-lx3.

Details like telescope and instruments

Data

Online data processing (Odp)

The Odp creates calibrated spectra online during the observations, stored in the so-called 30m files, and readable by class. In most cases, the observer works offline only with these files. However, in case of problems with the data, e.g. calibration issues, the observer needs to know to some extent what Odp is doing.

During observations, the backends take data and save them in streams in FITS format. These streams are merged with streams from other parts of the system, e.g. antenna mount drive, and also with messages, to be included in IMBFits raw data files. These are then combined by mira/odp to create calibrated spectra, usually on the antenna temperature scale TA*, and saved as 30m files. These in turn can then be read offline with class by the observer. Mira, class, greg are part of the GILDAS software package. Astronomical data therefore is created in several levels: level-1 are the streams, level-2 are the IMBfits files, level-3 are the 30m files. In case of calibration or other problems, it is possible to recalibrate data using MIRA, or even to recreate data from the streams.

Where are my data ?

• On the observers project account,

  • 30m data are found here: ~/observationData/mira. One file is created per backend and per day, e.g. FTSOdp20120105.30m

  • IMBfits raw data are found here: ~/observationData/imbfits. Their file name gives date, scan-number, backend, e.g. iram30m-fts-20120107s167-imb.fits.

What happens to my data ? Backup, Storage

We retain at least one copy of all 30m files, IMBfits raw data files, and project accounts at the observatory. Upon request to the computer team, we will retrieve data. Depending on when the data were taken, data are stored on different media. Most recent projects are stored on a local disk array, the project archive prArch and/or on Ultrium tapes. Older data are still available via DVDs, and CDs. Data streams are not regularly backuped.

How can I safe my data ? Use rsync, stupid !

• Assuming your project number is 999-11, change directory to the subdirectory on your local disk where project data shall be stores, and then copy the data over using rsync -rtvH --safe-links --bwlimit 2000 999-11@mrt-lx3:/vis/999-11/* ./

• Detailed information is given here (internal).

Next steps: user dp

Howto work with spectra: CLASS

Howto work with data cubes: GREG

Whom to complain to ? Help needed

Don't be afraid of "silly" questions, please!

This page is maintained by CK. Any comments are welcome.