Semester 97B observations October 1997 - January 1998


For Semester 97B, it is hoped that MERLIN observing time will be available for the first time in two frequency bands - C-Band (5 GHz) and K-Band (22 GHz). The 'frequency agility' development programme should have progressed to a state in which four of the six telescopes (the Cambridge 32m and the three E-Systems telescopes) can be equipped with both receivers at the same time and between which it will be possible to switch by computer control within a minute. As the Defford telescope does not operate at K-Band, (MERLIN K-Band observations have always been thus restricted to a reduced number of telescopes and consequently a reduced number of programme possibilities), the only telescope which will require a change of frequency will be the Mk2 telescope, sited at Jodrell Bank. A frequency change on this telescope should be achievable within a day, making it possible to consider one or more changes of operational frequency during the semester.

It should, of course, not be forgotten that if any programmes, particularly those investigating and monitoring variable sources, do not require the Mk2 telescope in the array, it will be possible to switch between the two frequencies throughout the observing programmes, thus effectively observing almost simultaneously in the two frequency bands.

The maximum angular resolutions at C-Band and K-Band are ~40 and ~8 milliarcseconds and the minimum rms noise levels in maps of continuum sources will be ~50mJy per beam and ~400mJy per beam for 12 hour on source observations respectively. The maximum bandwidth per polarisation for both frequencies remains at ~15MHz.

For spectral line work throughout the semester, users are referred to Section 3.4 of the MERLIN User Guide Version 1.1. However, the number of frequency channels per baseline to be divided between the four polarisations will be 512 for bandwidths of 2 MHz or less. The minimum total bandwidth is 125 kHz. The maximum number of frequency channels per baseline to be divided between the four polarisations for bandwidths of 16 MHz, 8 MHz and 4 MHz are 64, 128 and 256 respectively. Proposal forms and further information can be obtained via either:ftp

ftp.jb.man.ac.uk directory: pub/merlin/semester_97B, the web site or by email merlin@jb.man.ac.uk.


wlm@ast.cam.ac.uk