The CONT05 experience at Bonn correlator. Diary of some really intense days at Bonn correlator. First Teleconference: Participants are Bonn, WACO and Haystack correlators IVS scheduler and coordinator for the sessions. Topic discussed: Who should send media to whom Who is correlating what and how much time will it require? correlators are asked to give an estimate of the processing factor(PF = no. of obs. hours / no. of corr. hours). Bonn has to ask the astronomers when their millimetre sessions will be correlated to avoid a long queue at the correlator. Talk to Walter: We gently ask Walter whether we could monopolize the correlator for our CONT sessions, assuring him that there would be no R1 sessions during this period. We obtained the permission. Second teleconference: Participants are same as above. Topic discussed: Do we really have all the D-size modules needed to see us through the CONT05 sessions in the IVS pool? Speculation: probably not! Bonn seems not involved in the D-size dispute; we have to supply all stations with A-size and B-size modules. Warning to Don at Haystack who has to send disks to Tigo: Chilean customs officers are really picky and need a special declaration written in Spanish. Their customs clearance is really slow; an import normally takes 20 days to be custom cleared. Bonn confirms the possibility of correlating C0501 (the first one, Everybody will be eagerly waiting for the result of the first session), C0507, C0508, C0514 and C0515 (the last) Bonn gives an estimate of PF = 4 per session. Third teleconference: Partecipants are same as above. Topics discussed: After a lots of e-mail exchanges, the correlators conclude that they can manage to supply the modules to the stations, also thanks to the help of some stations that pursued or had already hidden in their secret reserve some D-size modules. Bonn charges itself to ship A-size and B-size modules as was discussed in the first teleconference. Final decision is made on who is correlating what: Bonn will correlate the session assigned to it in the second teleconference. Shipment: Media should be sent asap to stations. Bonn is to send modules also to stations that normally are supplied by other correlators. Find the station addresses in the list at the correlator. Some seemed terribly old: reporting as contact persons people who no longer work at the stations since decades. Bonn contemplated to use the normal post to send to Ny Alesund, so at least they will have the modules delivered to the station instead of to a near by island (poor postman). A courier reports that it is impossible to send modules to a station because the courier's software does not allow them to insert the six-digit postcode. The operators at Bonn find themselves overloaded by the amount of media to ship, since astronomy is also shipping disks to the stations for the millimetre campaign. Finally all the disks are out and the stations confirm receipt. One module is misteriously missing. After a lot of e-mail exchanges among Algonquin, Bonn and the courier, it is discovered that the module was by mistake send to Effelsberg for the astronomy millimetre campaign. Tigo warns us that they still have the modules held in customs. They solve the situation using some smaller modules already present in their pool. Exchange of e-mail with HartRAO: they want to confirm the address in Bonn and to know all the procedure, that make German customs officers happy. Many thanks Marisa. C0501 Preparation of correlator control files, correlation and post processing: We assume since C0501 is a R1-like session that the setup to be used is the same as for the R1 session ( this idea saved us later from having to recorrelate). TGEN, the program that handles the transfer file (file containing all the scan names and baselines involved in the scans and correlation mode), is not working properly. It reads all the correlator contol files before creating the transfer files (sort of a last check before correlation starts), but it can handle only a certain number of lines. Since the CONT sessions involved 11 stations the sum of the number of lines it had to read was greater than the maximum. Ok. Don't panic: we can split the files in two parts and concatenate the output at the end. Easy, but tedious and can introduce errors, which become difficult to be find (e.g. would you be able to find a missing semicolon in 10000 lines?). Thanks to Jason who is sending us in advance the list of files with start byte and end byte (in jargon DirList) we can prepare in advance the part of the file concerning Tsukuba. The media arrive in Bonn, and all the above stuff is done (hopefully without errors) Trial correlation: all looks fine, the stream correlation can start. C0501 runs smoothly and unattended at night (the beauty of Mark5). The actual PF is 2.96. The data are checked, fringe fitted and the database is submitted. David sends an e-mail thanking Bonn for the fast turn around.. it is really nice to receive such e-mails. C0507 & C0508 Preparation of correlator control files, correlation and post processing: These two sessions are recorded on the same module. We had seen that before: last year one station recorded a T2 and an OHIG session on the same module. All the control files are ready before the media arrive in Bonn. Same problem with the program TGEN. We start to wonder how the other correlators managed it and send an e-mail to ask. The answer leave us agape. A new version of TGEN exists since July 2005 and is installed in Bonn too. By reinstalling TGEN the problem disappears; at least the next two CONT will be less tricky to prepare. Correlation starts and runs smoothly at a first sight. While the correlation is running, Brian suggests a new correction for the clock_offset: he collected all the gps to fmout data from the logs and fit a linear model to the data. Unfortunately we cannot interfere with the correlation: C0508 is already correlated and C0507 half way through correlation, but we can use those values for C0514 and C0515. The correlation of C0508 finished, the data checked and the database is submitted. C0514 & C0515 Preparation of correlator control files, correlation and post processing: Control files are prepared and TGEN works as it should. Some problem occur in shipping. HartRAO disks are hold in Frankfurt and the courier does not know where and why. In the mean time also the media for the first R1 session of October start to arrive.. queue in sight. The new directive from IVS is to correlate C0515 first since it is an R1-like session then the R1 then C0507 and C0514. We will do so. C0515 correlation runs smoothly. Data are checked, and fringed. Database is submitted. In the mean time also C0508 database is submitted. Mike sends as an e-mail a warning to us of a problem known to them from the R&D sessions; the Station Units (SUs) sometimes introduce a deterministic but spurious signal which is 100 % correlated and, of course, need to be eliminated. Oops... we did not know that! But after Mike sent us an example we notice that the spurious signal is present also in all our CONTs. Another e-mail arrive from WACO. A last-minute decision about how to correlate and fringe fit the data is made. Well as said before for C0501, since we used the setup for the R1 we had not to recorrelate but only to refringe. Actually had also a recorrelation be needed we would have not been able to perform it since C0501 media were already released; the world keeps turning and the geodesists go on to measure it, so media are needed at the stations to go on with the routine sessions. In the mean time C0514 correlation finishes. Since we have to refringe everything, we solve also the spourious peak problem mentioned by Mike. Done and resubmit. C0507 The saga The C0507 database is also submitted and Bonn sits down to relax, mistakenly thinking that the CONT05 sessions are over. An e-mail from David arrives: some C0507 baselines had "amplitude problem". Again, the SUs are guilty (it starts to become easy... if something is not working than blame it on the SUs. Sigh.. with Mark5B we will loose this convenient scapegoat). Roger helps us to make our life easy; he changes the program to fringe the data, so that at least these dubious scans could be easily spotted. Anyhow, we had to recorrelate. Correlation finishes, data are checked again and look good. Time to resubmit the database. It seems an easy task, but for some reason it is taking a long time (somehow a sort of "ghost file" from the previous submission is spooking around). But we will not surrender. In the end, due to a problem with the server in Leipzig the X-band part of the database is submitted. We will ask help in Leipzig. The reply is fast and the S-band is also submitted. Now we are really finished with the CONT sessions, it remains only to write our experience during the CONTs... and that is what you are reading!