===================================================================== Joint VLBI Observations with the EVN CODE OF PRACTICE FOR NON-EVN OBSERVATORIES R.W. Porcas (MPIfR) INTRODUCTION ------------ Observatories outside of the European VLBI Network frequently give observing time for VLBI observations together with the EVN. Such joint observing can enhance the performance of the EVN alone and may sometimes be critical for achieving the scientific goals of a VLBI project. In the first instance, the Principal Investigator (PI) is expected to contact the observatory with a request for observing time when submitting a proposal to the EVN. If such a proposal is accepted by the EVN Program Committee (EVNPC) it will be scheduled in one of the advertised EVN observing sessions. Execution of the program at EVN observatories is the responsibility of local staff, made according to procedures which are coordinated by the EVN Technical and Operations Group (TOG). An outline of these procedures which it is useful - in many cases essential - for any participating observatory to follow, is given here. The PI and non-EVN observatory staff are jointly responsible for the successful outcome of observations outside of the EVN and are therefore urged to keep in close contact with each other. TECHNICAL COMPATIBILITY ----------------------- All EVN proposals are subject to a technical review by the EVNPC, to ensure that the proposed observations and correlation are technically feasible with the EVN. PIs are encouraged to use standard frequency set-ups, polarisations and recording modes, where possible. The EVNPC will try to check for known incompatibilities with any non-EVN antennas requested but, ultimately, the PI and the relevant non-EVN observatory staff must be responsible for this. EVN BLOCK SCHEDULE ------------------ A block schedule for each EVN observing session is made about 6 weeks before the start by the EVN Scheduler, Dr. R. Porcas. Please ensure that he knows whether your observatory is taking part, and in which projects. Address any enquiries to: evn@mpifr-bonn.mpg.de SUPPLYING TAPES --------------- Observatories participating in EVN observations are supplied with tapes, where necessary, about 6 weeks before the start of the session, according to the requirements of the Block Schedule. The distribution is arranged by Dr. Walter Alef (alef@mpifr-bonn.mpg.de). Tapes will normally be sent from one of the correlators (JIVE, BONN or VLBA). Tapes can be sent to non-EVN observatories, provided that their participation has been confirmed, the type of tape (thick or thin) has been specified, and an exact shipping address is known. Contact W. Alef to make your tape requirements known. All observatories are strongly urged to use the NRAO "TRACK" program for monitoring tape shipments, both to and from observatories. Input to the program is at: http://magnolia.nrao.edu/track/ Before using this system it is necessary to register your site and to obtain a username and password. Contact Robyn Harrison: vlbatape@nrao.edu PROJECT SCHEDULES ----------------- A schedule file describing the observations for each project is created by the PI. This is normally a VEX file for running with the NASA- Goddard Field System (FS). ==> Please make sure your observatory runs an up-to-date version of the field system. The PI will deposit the schedule file on the EVN file-server, 2 weeks before the start of the session. Schedules should be retrieved from the server by participating stations using ftp from : vlbeer.ira.bo.cnr.it as user "evn" (the password can be obtained from any EVN observatory friend, or telephone Bob Campbell at JIVE:+31 521 596534). Experiment files are in directory: vlbi_arch/mmmyy where mmm = first 3 letters of the MONTH IN WHICH THE OBSERVATION STARTS, and yy = last 2 digits of the year (e.g. jun00). Schedule files have names xxxxx.skd where xxxxx is the EVN project code as it appears on the EVN Block Schedule. ====> Contact Tiziana Venturi (tventuri@astbo1.bo.cnr.it) if any problem is encountered using the server. OBSERVING ASSISTANCE -------------------- EVN observations are made "in absentia" at each EVN observatory by the VLBI observing "friends". It will be assumed that observations at non-EVN observatories will be made by local observatory staff. Contact the PI of the project if further information or assistance in needed. TAPE SHIPMENTS TO THE CORRELATOR -------------------------------- In order to prevent any delay in correlation, observatories are asked to ship the recorded tapes to the designated correlator within 1 week after the end of the observation. Each observatory is expected to cover the cost of the tape shipment. Please make sure the tapes are sent to the correct correlator, as indicated on the EVN Block Schedule. JIVE CORRELATOR ===> Joint Institute for VLBI in Europe att: R.M. Campbell Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands BONN CORRELATOR ===> Max-Planck Institut fuer Radioastronomie Auf dem Huegel 69, 53121 Bonn, Germany VLBA CORRELATOR ===> VLBA Array Operations Center (thin tapes only) 1003 Lopezville Road, Socorro New Mexico 87801-0387 USA OBSERVING LOGS, CALIBRATION DATA, ETC ------------------------------------- Field system logs should be deposited within a few days of the end of the observations on the EVN file server, in the same directory as the schedule. The file name should be of the form xxxxxss.log (where xxxxx is the experiment code, and ss is the observatory 2-letter code). If possible, please try and conform to the "Bologna Rules", a set of procedures which EVN observatories should follow. (Consult: http://www.nfra.nl/jive/evn/tog/bol_rules/bol_rules.txt) System temperature measurements made under FS control during the observations will be extracted from the FS log. For calibration of VLBI visibility amplitudes it is also necessary to have knowledge of the antenna gain (K/Jy) and any variation with elevation. If a standard gain curve is available, non-EVN observatories might consider making this generally available to VLBI users via the /cal directory on the EVN server. Please contact Dr. Cormac Reynolds (reynolds@jive.nl). GPS timing data for monitoring the offset of the station clock can be useful for correlation. If possible, please make sure that GPS measurements are made during the observations and written in the log.