Notes from Commissioning Coordination Meeting 27 September 2002 1. Observing Program Checkout There has been very little progress this week apart from Anish, who is making good progress. The main problem has been that we let the observing schedule get too full. Ron has been performing Thilker's observations for him through the week. He will be performing checkout for 2C19 (Yusef-Zadeh) on Saturday night/ Sunday morning. Ron and Jim are scheduled to start the checkout of 2B10 (Henkel) on Tuesday evening. Ron has been through all the 2C proposals, and we have selected five new projects which Frank will be responsible for. These are: 2C-04, 2C-24, 2C-38, 2C-59 and 2C-63. All of these should be very straightforward L-band proposals, so most of the checkout really should be confirming with the PI that we've correctly understood their intentions. Dana's projects are now essentially part of the baselines investigation. Ron noted that that there are 29 spectral line programs in the 2C batch; 9 are already in the "Scheduled" queue or the "Active Checkout" queue. 2. Spectrometer status Ray and Rich found the causes of the bumps in the autocorrelation funtion, and a way to fix them. It's going to involved a day or two of work. Details are a bit too messy to explain here. Rich will spend a day or two next week cleaning this up while it's still in his head, and then get back on to mode testing. The spigot people finally got three pulsar spigot modes working well using a pulse generator input. There are several more to test at a later date. As with most things, getting the first one was the hard part. Plan is for Ray to come up for about two days sometime in October. In the meanwhile, we can probably take some data for Dave Kaplan and let him analyze it. We've made little progress this week with Spectrometer checkout. The "quantized noise" problem that Dave discovered two weeks ago turns out to be an artifact of aips++ and the spectrometer pass-bands going to zero at the edges. The calibrated data is converted in the MS to a 16-bit integer via a simple scale and offset. When the system temperatures are spuriously large, the normal signal levels are squashed into only a few bits. There is a temporary fix for this of simply turning off compression in the MS. The strong baseline shapes RMP discovered one week ago in one polarization of one IF are caused by a change in the IF gain half-way through the ON scans. Hence the (on-off)/off calibration fails. Frank and RMP were scheduled to do more Spectrometer checks this morning; that failed due to Spectrometer hardware problems. We will try again tomorrow. Other commissioning news Kim has discoved evidence in the QD detector data that above 50deg the tip of the feedarm deviates from the linear structure model predictions. Although this is strictly a focus-tracking problem, it is most easily characterized by its affect on pointing, and it appears to be qualitatively of about the right size and shape to explain the current pointing performance, although considerable further analysis is required. RMP plans to run pointing tests over this weekend to obtain simultaneous QD and pointing data to allow us to investigate this further. Ron and Richard will arrange a meeting next week to start planning the engineering and commissioning requirements to proceed with K-band commissioning. 3. Software Nicole reported that M&C v3.7 was successfully released on Wednesday. The Beta version of the new Configuration Tool was also released yesterday. Comments are requested. The new development cycle starts on Monday and should culminate with release of v3.8 on 30 October. Nicole distributed a status summary for Software Development activities. Most projects are proceeding well. The Engineering Measurement System task moved to "red" status owing to some scheduling problems and the unexpected network outage. They expect to recover next week. Richard noted that the observer's status screen needs to take on some priority soon. This will have to be balanced against continued work on the Configuration Tool and will be discussed in a separate forum. 4. Baseline investigations Dana reported that he, Rick, and Roger met early in the week to discuss priorities for baseline investigations. Work on X-band baselines will take on top priority now, but the group feels that some time should be invested on the ongoing work on L-band to maintain momentum there. Roger sent an email around earlier in the week about work on the fiber optic IF system. The original model optical modulator (without the ALC modification) has been installed in one channel to provide a performance benchmark. Roger did some tests at L-band and found some receiver problems that are being addressed. Mike Stennes is working on the K-band receiver. Some mock observations will be taken in the Equipment Room next week with the receiver connected to the Spectrometer. 5. AIPS++ News Joe M. reported that a number of improvements / enhancements have been underway. Notable among these is the multi-IF capability, which should be installed Monday. Total power OTF mapping is now installed. This was used to reduce the Thilker M31/M33 data. Joe is getting a recipe in place to make this easy. Bob checked in changes that disable the data compression and scaling feature that are discussed above. Today, Bob also checked in a fix to the problem with GBT logview. Joe noted that he would like to give a seminar on some of the new AIPS++ features when he is in GB the week of 13 October. Phil will set this up. 6. Action summary The two actions from last week were o Rick, Dana, Roger meet to decide baseline priorities. o Comments due in to Richard on multi-beam operation proposal. The first was done and is reported above. Richard also received a few comments, and that action is also closed. Actions for next week are Action 27sep02-1: K-band commissioning plan complete and ready to be reported on 4 October (Ron) Action 27sep02-2: Feedback on the Configuration Tool due in to Nicole by 10 October (Commissioningg Staff) 7. Other business Ron showed the excellent HI images obtained as part of the Thilker program. RMP & PRJ // 27 Sep 2002