The 19-channel MPIfR bolometer, which was installed last winter on the 30-m telescope, will again be available this winter, presumably between December and March. This receiver showed excellent performance during last year's observing run.
The On-the-Fly observing mode (OTF) is implemented for heterodyne observations (still with some limitations concerning data acquisition rate and reduction). In this mode, the telescope beam drifts continuously across the source, while data are dumped every 1s (or 2 s, depending on the number of frequency channels). Any scanning direction can be chosen and successive scans can be concatenated to make a map (like in the bolometer `mapping' mode). Individual drift scans can have any length; they are interleaved with OFF source reference subscans of any duration. This mode ensures a better homogeneity of the data and can make a much more efficient use of observing time.
Up to 4 receivers can be used simultaneously for OTF observations. The backends can be the filter banks and/or the autocorrelators. OTF observations were carried out successfully since December 1995 on several programs. The large acquisition rate causes data storage and handling problems: although a new version of CLASS has been developed, the software is not yet user-friendly and remains experimental. Because of these shortcomings, the OTF observing mode is still restricted to programs involving an astronomer of the IRAM-Granada team, who should be responsible for the technical aspects and for the data reduction. Please contact Drs. H. Ungerechts (ungerech@iram.es) or W. Wild (wild@iram.es) at IRAM-Granada well before the deadline for more information.