JLS Current Status

Date: 25 August 2008

TELESCOPE	There are no problems to report.
SCUBA-2	FIRST LIGHT FOR SCUBA-2 !! The SCUBA-2 team achieved this important milestone in the project when they detected Saturn during tests of the scan observing mode.
HARP/ACSIS	The current status of HARP/ACSIS is summarised below: H03: missing from the cryostat since delivery. H14: currently unusable due to large oscillations in the mixer. This receptor has now been switched off in the data acquisition. Receptors H09 and H12 are operational but have high resistance in series with the junction. Because of these problems, data from receptor H09 below 340 GHz are now masked out by the ORAC-DR pipeline processing (note that they are still in the original time-series spectra). The tuning tables were completely remeasured and fine-tuned across the whole range. These have not yet been installed as there are one or two small tuning ranges which have yet to be satisfactorily characterised. The new tunings show very little deviation from the original, so it will not have a large effect on performance. The new mixers are under construction with the devices being mounted into the blocks as this is being written. If work progresses according to plan, then we can expect to receive and install the receptors into the cryostat sometime in November, but this is entirely dependent on JAC receiving the devices in time, and on the JAC's engineering team's schedule. Receptor H08 failed for a short period during the month. It is now working again. During troubleshooting, it became apparent that this was due to a CANbus problem (a communications device on the instrument) which resulted in voltages not being set properly. The investigation into the CANbus communications is ongoing. A ground loop in the IF system was also rectified at this time.
CALIBRATION	No change from previous reports.
JLS PROGRESS	The latest JLS observing run, supported by the GBS team, has just completed. We thank the observers for coming out and supporting the run. There was moderate success as the weather was quite good through the run (too good at times), with 20.6 hours observed for the JLS out of the 60 hours available. The current progress is shown in the bar charts below, illustrating the amount of time charged to each survey and the current completion rate (for just the HARP survey components). A reminder that there is a new version of the ORAC-DR pipeline which we are encouraging the JLS teams to use, provide feedback to us if necessary. This version of the pipeline uses iterative techniques to deal with baselines more stringently and visibly produces better results than the previous version. If you would like a pre-release version (which currently only runs on 64-bit linux machines) then please get in touch with us.
	For reference, the JLS allocations are given here.
ARCHIVED REPORTS	An archive of previous JLS status reports is accesible from the links below:
	21 July 2008 9 May 2008 18 April 2008 24 March 2008 28 February 2008 15 February 2008 31 January 2008

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