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JCMT Note from the Director26 October 1999The upcoming JCMT Advisory panel and Board will address a number of issues. I invite users to give their input as part of the decision making process. The first part of this note is to alert you to these. The second part is to inform you of some operational decisions that have been, or will soon be forced on us. Overall you should note a number of projects are coming to fruition. The Observatory and Telescope Control projects are almost complete and the major observatory project at the current time, the surface upgrade, is coming to a conclusion with the imminent arrival of the new fast holography system and the panel adjuster electronics system. Testing and commissioning of the 21 micron active surface will commence in the spring. The next major development project, the linking of the JCMT with the SMA is also ramping up and work will begin in earnest before Christmas. Remo Tilanus will be the JCMT project Scientist for this project. This offers a hugely and exciting prospect for subarcsecond astronomy to users.
(a) Issues for the Advisory Panel and Board1. New instrumentsAs you will undoubtedly know, there are three potential new instruments vying for support and funding. These are HARP-B, HARP-D and SCUBA-2. Below lists a top-level briefing on each:HARP-B This is a 16-element 350 GHz SIS focal plane spectroscopic camera to be housed on the right-hand Nasmyth platform and fed through the encoder bearing by a K-mirror optical train. It is already well along on the approval route, having had a very successful CoDR in March and a K-mirror PDR in September. However, due to problems with UK staffing levels, HARP-B still needs formal Board approval now that the project has been reorganised to reduce the requirement on UK staff effort. MRAO are the project leaders along with the UKATC and HIA Victoria. The science case is now on the web at MRAO with a link from the JCMT homepage. HARP-D This is currently being worked up into a proposal by the Netherlands. It will be a clone of the MPIfR CHAMP array currently on the CSO, but operating at D-band. It will be built jointly by SRON and the MPI für Radioastronomie (group of Karl Menten) and will be on loan to the JCMT for at least 2.5 years, with a possibility of another year before moving to the ALMA site. It will have 16 elements, with minimum spacing on the sky. It can provide 2 GHz of bandwidth for each detector. To obtain optimum system sensitivity the design includes cold optics (15K) and an optically tuned single-sideband separation. The intention is not to use a beam de-rotator as the observing strategy will allow sufficiently short observations so that the rotation corrections can be done in software. The timescale is about 3.5 years. The science case is now on the web at Leiden with a link from the JCMT homepage. SCUBA-2 SCUBA-2 is proposed as a wide-field (8x8 arcmin minimum) twin-wavelength (850/450 micron) camera operating with new technology detectors, He-3 cooling and no moving parts. It is designed to mount at the left-hand Nasmyth, be simple to operate, reliable, background limited and devastatingly powerful as a mapping facility. The new technology detectors are more akin to CCD-type of detectors, being directly illuminated in the focal plane with 0.5 F lambda pixel spacing rather than the 2 F lambda ?horn-feeds previously typical of these wavelengths. The timescale for SCUBA-2 is 4 to 4.5 years. The science case is now on the web here with a link from the JCMT homepage. Unfortunately, there is inadequate funding remaining in the Development Fund to support all three instruments. Clearly, we wish to have all three and so I anticipate there will be pressure to extract additional funds from the agencies to support this exciting programme. To ensure the success of this it is important that you lobby your representatives on the Advisory Panel and express your priorities. While we will continue to fight for all three instruments, the Board will undoubtedly wish to have a prioritised list of the instruments. This has already been provided by the Panel last November (and reinforced in May). This was SCUBA-2 (ensure enough funds remain to build it), HARP-B (go ahead and build it now), HARP-D (go ahead with low-level R&D prior to construction). The situation is now clearer in that SCUBA-2 is better defined (and much more expensive than anticipated) and there is a clearer way to achieve a D-band array. If, after reviewing the scientific cases, you disagree with this priority order, let your views be known. I will assume silence equals agreement. The Advisory Panel meeting is on November 8/9.
2. Guaranteed time for instrument builders.The Board has agreed the principle of guaranteed time to instrument builders and I was charged to come up with an implementation plan. I polled the builders for their views and from the responses I have made a proposal (below). This will be commented on by the Advisory Panel, and ITAC. Please make your views known to your panel representatives if you have strong agreements or disagreements with this. Note, the Board have approved the principle, this is an implementation debate.(i) Time should be linked to the complexity of the project with the following being a first suggestion: small 5, medium 10, large 15 shifts. A backend (for example) should count as an instrument. Other instruments, such as RxH3, should be treated on a case by case basis. (ii) There should not be a penalty clause (iii) The science programme should be open to the Co-I^Òs involved in the instrument, the case should be adjudicated by the ITAC and should come from a subset of the original science case for the instrument (where appropriate).
3. Big observing programmesThe user community has already been polled on this. There were 23 replies: 13 from the UK, 5 from Canada, 3 from the Netherlands and 2 from the USA. I am most grateful for those respondents for taking the time to reply. The replies were carefully thought out; respondents had clearly given the issues serious thought and provided some helpful and interesting suggestions that will be incorporated into a paper for the Board.
(b) Operational issuesSCUBAThe SCUBA upgrades went very well and the microphonics have been greatly reduced by the new ribbon cables. Also, preliminary results show that the new blocking filters have given improvements to the flux conversion factors at 850 and 450, and that the wider band 450 filter shows a large improvement over the standard 450 filter. NEFD data have been harder to come by but preliminary estimates are that there are gains at both wavelengths, more at 450 than 850, which was expected.That was the good news. The bad news is that although SCUBA looked excellent after cool-down, best ever in fact, four days later it developed a noise problem on the array. Two mini-warm-ups have failed to cure the problem. This also happened in July and the cure then was a full warm-up with baking and extended pumping. Although the symptoms are not identical, we are now embarking on an extended warm-up. Watch this space.
TSS shortageThe second operational matter is that a second Telescope System Specialist is resigning as from December. This will mean that from then until we recruit and train-up replacements, we will be unable to support sixteen hour observing nights on the JCMT and will have to resort to something like twelve hour nights for two-thirds of the time. It is anticipated that these hours will run from something like 8pm to 8am.Clearly this will be disruptive to a number of programmes already allocated time this semester. I will be liasing closely with the TAG Chairs to try and ensure that these are treated fairly and that implications for semester 00A are understood at the ITAC meeting. Professor Ian Robson Director, Joint Astronomy Centre Director, James Clerk Maxwell Telescope |