## Observation and Data Reduction

In 2018B semester, observations and user supports for EAVN will be carried out on the basis of the current KaVA's operation scheme.

## Preparation of an EAVN Observation

After the acceptance of proposals, users are requested to prepare the observing schedule file two weeks before the observation date. The observer is encouraged to consult a contact person in the KaVA/EAVN Array Operation Center (AOC) and/or the assigned support scientist to prepare the schedule file under the support of the contact person and/or the assigned support scientist. The schedule submission should be done by a stand-alone vex file. The examples of KaVA vex file are available at the KaVA web site:

http://radio.kasi.re.kr/kava/kava_observing_preparation.php

Detailed information about preparation and submission of a schedule file for Tianma and NRO45 will be announced when distributing the proposal review results.

On your schedule, we strongly recommend to include at least two fringe finder scans, each lasting 5 or more minutes at the first and latter part of observation in order to search the delay and rate offsets for the correlation.

For EAVN which includes the large telescopes (Tianma and NRO45), regular pointing check is necessary at both 22 and 43 GHz. You should leave a 8-15 min gap every ≤ 1-2 hr in your schedule file to allow this. Pointing check is done by the local operators. In addition, we strongly recommend to include frequent scans of a maser source and/or a bright compact continuum source located within 15◦ from the target. This allows a cross check of the amplitude calibration for Tianma and NRO45 along with the usual a priori method.

We request PIs to specify their correlation parameters at the beginning of the vex file for proper correlation processing. In particular, PIs who request for sub-array or dual-beam observations for KaVA should provide a frequency matching table for the correct correlation.

EAVN ( East Asia VLBI Network)