Notice Schedule Preparation Data Reduction
Notice to EAVN Users

We would like to inform you about the EAVN operation and user support as follows.

  1. Following email accounts are available for proposal submission, observation, correlation and user support.
    • eavnprop@kasi.re.kr :
      proposal submission and informing its result
    • eavnobs@kasi.re.kr :
      observing schedule submission, observation related requests and questions for the accepted proposal only.
    • kjcc@kasi.re.kr :
      correlated data distribution and correlation related requests.
    • eavnhelp@kasi.re.kr:
      general questions from the users including scheduling, observations, systems, and so on (regardless of the proposal acceptance).
    ※ We strongly recommend to use official email above rather than the personal email for the EAVN
  2. Schedule Preparation
    • You will be notified when your observation is scheduled by the EAVN scheduling officer. Then, your schedule file must be submitted to eavnobs@kasi.re.kr one week before your observing date.
      ※ If your schedule submission is delayed, your observation may not be assigned.
    • For the EAVN schedule submission, PI should submit both a stand-alone vex file and a SCHED key file. In the vex file, please specify calibration procedures for hot/cold calibration, sky dipping, pointing, etc. Calibration procedures of EAVN can be found here.
    • We also request PIs to specify your correlation parameters at the beginning of the vex file (in case of EAVN observation) or in the key file (in case of KVN observation) for proper correlation processing.
      ※ In particular, PIs who request for sub-array or dual-beam observations for EAVN should provide a frequency matching table for the correct correlation.
    • Please include at least two fringe finder scans, each lasting five or more minutes at the first and latter part of observation in order to search the delay and rate offsets for the correlation. We strongly recommend placing those scans at least every two hours.
  3. Observation
    • Your observations are fully covered by EAVN operation team.
    • After the observation, the result will be reported to PI in two weeks by eavnobs@kasi.re.kr
    • Target of opportunity (ToO) observations will not be able to be schedule on the desirable date if observations with other network (e.g. KVN+VERA, KVN+EVN etc) has already been scheduled.
  4. Correlation and Data Validation/Distribution
    • Daejeon correlator or DiFX software correlator output is a standard FITS file. The first correlated data inspection is done by DQA (data quality analyzer) and if there is no problem this will be provided to the PIs via FTP including auxiliary files such as ANTAB, Tsys plots etc.
    • FTP address for downloading the data will be informed to the PI’s email that you submit the schedule to eavnobs@kasi.re.kr.
    • After one month (in case of EAVN) and two weeks (in case of KVN) later of a correlated data distribution to PIs, disk modules which contains raw observing data can be recycled without notice. Therefore, PIs should investigate the correlated output carefully and if there is issue to discuss, please email us (kjcc@kasi.re.kr) about that.
      ※ In order to request re-correlation or raw data keeping, PI should provide adequate evidence.
A Quick Start Guide for the EAVN Observing Schedule Preparation
1. Overview

From 2022B season, the EAVN will request the principal investigator (PI) of the successful proposal to submit the observing schedule using the NRAO SCHED. In order to prepare the SCHED-based EAVN schedule, please use the following templates in accordance with your science cases. If any help is needed, please contact the EAVN Array Operation Team (AOT; eavnobs@kasi.re.kr) and User Support Team (UST; eavnhelp@kasi.re.kr).


2. SCHED

SCHED is a program for planning and scheduling for the VLBA and VLBI observations developed by NRAO and is now widely used for other VLBI networks. Please visit the webpage for the SCHED documentation (http://www.aoc.nrao.edu/software/sched/index.html).


3. SCHED for EAVN

For the EAVN scheduling, modifying the sample .key files for each observing mode is recommended. The station and location catalog files of the EAVN that include detailed information of the EAVN telescopes (e.g., telescope coordinates, slewing speed, sky lines and backed types etc) is specified in the .key file.

example of EAVN catalog files for the 2024B season


4. EAVN sample .key files

The SCHED sample .key files are available for the following EAVN observing modes. Please use one of these sample .key files as templates for creating your EAVN observing schedule.


5. General Guidelines
  • Note: In the .key file, a cover information for the experiment is necessary. the experiment code provided by the EAVN scheduler, PI related information is needed. The correlator setup also needed to be specified according to the proposal cover sheet.
  • Frequency setup: The example of frequency setup is given in the template, but you may need to modify it in case of spectral line observations and other purposes. In this case, please see the EAVN status report (https://radio.kasi.re.kr/status_report/status_report.php?site=eavn) in order to check frequency ranges and corresponding modes.
    • The frequency setup of Nobeyama 45m (Nb) should be fixed. Please do not change.
    • Frequency agility of Sejong (Kv) is currently limited.
  • Calibration procedures: Due to various sizes and specifications of EAVN telescopes, users need to pay attention to the calibration procedures when organizing the observing scans. The necessary time required to proceed is summarized as follows. Please note that when participating telescopes are mixed, please take the larger scan gap (time) to ensure the completion of calibrations.
    • Sky opacity measurements
      • In general, a calibration procedure to measure the sky opacity will be conducted before and after the observation. In case of KaVA, this calibration procedure is specified as “SECZ”
      • “SDip” in the “$PROCEDURE” section of the example vex file, so that the telescope control software (so called field system) proceeds automatically. Other stations except KaVA will be manually performed at each site.
    • System temperature calibration
    • For amplitude calibration, it is necessary to proceed with the appropriate calibration such as chopper wheel or noise diode etc. This procedure is implemented in the field system of KVN and VERA, so called “R_SKY” in the “$PROCEDURE” section of the example vex file.
    • We recommend you to give 30 seconds
    • Pointing calibration (if necessary, during the observation)
      • For the KVN, the automatic pointing procedure is implemented in the field system. It is highly recommended to insert the pointing calibration procedure for the KVN hybrid mode (simultaneous K/Q/W/D-band observations). A 30-60 minutes interval for the pointing of KVN is recommended.
      • It takes 2.5 minutes to check the “cross-scan pointing calibration” for a bright continuum source and the “five pointing calibration” for a strong maser source, as shown in the vex file of the sample vex files to “CROSS” and “FIVE”, respectively.
      • It is not necessary for other stations.

6. A Step-by-Step Guide
  1. SCHED preparation
    1. Choose one of the sample .key files that is most similar to your observation. - (e.g.) ‘e22c5.key’
    2. Copy the EAVN catalog files to the same directory with the sample .key file. Then, you have three files (one .key file and two .dat files) in your directory. - (e.g.) ‘e22c5.key’, ‘station_EAVN_2022B.dat’, ‘location_EAVN_2022B.dat’
  2. Modify sample .key file
    1. “Cover Information” section
      Modify cover information with yours.d. The ‘expcode’ given by the EAVN scheduler should be use Please make a note at the ‘note1’ or ‘note2’ if you have any special request for your observation (e.g., matter that require attention for observations & correlation)
    2. “Correlator Information” section
      Modify correlator information according to your correlation request. For instance, ‘coravg =’ as a correlator average time (i.e., accumulation period), ‘corchan’ as a number of spectral channels (FFT points) per baseband channel (IF) etc. - (e.g.) coravg = 0.8192, corchan = 256
    3. “Standard Source and Station Catalogs” section
      Please check the path of the EAVN catalog files.
      - (e.g.) stafile = ./station_EAVN_2022B.dat
      locfile = ./location_EAVN_2022B.dat
    4. “Setup Files” section
      The frequency setup of each EAVN telescope is assigned according to the observing mode. While a frequency setup is the same, the name of each frequency setup (e.g., ‘setinit = GEO1S’) can be different because the different name at the ‘setinit’ can be often used to distinguish calibration procedures.
    5. “Scan” section
      1. Please modify observing date and time to start and stations. Note that do not specify stations that are not allocated to your observation!
      2. Then, please modify the ‘source’, ‘dur’, ‘gap’ etc in order to assign scan time, scan gap and target source for each scan. Please note that the different name of ‘setup’ is used to classify different calibration procedures that are automatically executed in case of KVN and VERA.
      3. Scan gap should be enough to carry out the proper calibration procedures (see section 5. calibration procedures in order to check the calibration time required) including telescope slewing time if necessary.
  3. SCHED Execution
    1. Execute the SCHED with your .key files on your machine.
      (e.g.) sched < e22c5.key If successful, several files are automatically generated. Please check “.vex”, “.sum”, and “.flag” files. In particular, “.sum” file contains very useful information.
    2. If plotting is wanted, you can check your observing schedule with plots by typing “plot schedule = xxxxx.key /”. Please check the details at the
      "Running SCHED: http://www.aoc.nrao.edu/software/sched/index.html#x1-3030004.2".
  4. Schedule Submission
    For your observing schedule submission, the compressed file (e.g., zip file) of all SCHED output files with the .key file for your experiment is required and sent to eavnobs@kasi.re.kr.
Data Reduction

EAVN DataReduction sample

For the data reduction of VLBI observations using EAVN, one can find useful information in the next pdf file, Amplitude_calibration_guideline_of_TMRT_and_NSRT.pdf


Data download

              $ wget https://radio.kasi.re.kr/eavn/data_reduction/EAVN_DataReductionScripts.tar.gz

Extract a tar file

              $ tar zxvf EAVN_DataReductionScripts.tar.gz

Directories and sample files included in the tar file

              EAVN_DataReductionScripts.tar.gz
              ├── 1.KaVA_PR_K-band_Line-Cont_Pairs(Sakai)
              │   ├── Input
              │   │   ├── ANTAB_Abeam.TXT
              │   │   ├── ANTAB_Bbeam.TXT
              │   │   ├── K20082A.A-APPLY2A-SN.TXT
              │   │   ├── K20082A.B-APPLY2B-SN.TXT
              │   │   ├── Maser-flagged-KVN.txt
              │   │   ├── QSO-flagged-KVN.txt
              │   │   └── R20082A.A-NO1.PLUS.TBIN.1111
              │   ├── KAVAPR.001
              │   ├── Output
              │   │   ├── Cont-SN4.ps
              │   │   ├── Cont-SN5.ps
              │   │   ├── G034.84-CP.PS
              │   │   ├── Selfcal-SN.ps
              │   │   ├── Tsys_A.ps
              │   │   └── Tsys_B.ps
              │   └── README.txt
              ├── 2.EAVN_PR_K-band_Cont(Xu)
              │   └── EAVN_PR_cont_sample_Xu.txt
              ├── 3.EAVN_Imaging_C-band_maser(Sugiyama)
              │   ├── sample-EAVN-Cband-line-step1.txt
              │   ├── sample-EAVN-Cband-line-step2.txt
              │   ├── sample-EAVN-Cband-line-step3-withdifmap.txt
              │   ├── sample-EAVN-Cband-line-step4-withdifmap.txt
              │   └── sample-EAVN-Cband-line-step5.txt
              ├── 4.KaVA_Imaging_K-band_maser(Hirota)
              │   └── sample-KaVA-lineimage_SF_Hirota.txt
              ├── 5.ACFIT_procedures(Hirota)
              │   └── sample-acfit_SF_Hirota.txt
              └── __MACOSX
                  ├── 1.KaVA_PR_K-band_Line-Cont_Pairs(Sakai)
                  │   ├── Input
                  │   └── Output
                  ├── 2.EAVN_PR_K-band_Cont(Xu)
                  ├── 3.EAVN_Imaging_C-band_maser(Sugiyama)
                  ├── 4.KaVA_Imaging_K-band_maser(Hirota)
                  └── 5.ACFIT_procedures(Hirota)