GBT Operations and Commissioning Meeting 22 October 2004 AGENDA 1. Az track, antenna Report -- Phil for Bob 2. Observing News -- Ron 3. Scheduling Status -- Carl 4. Frontends, IFs, and Spectral Baselines -- Roger 5. Spectrometer Status -- Rich 6. Software Status -- Amy, Nicole 7. Project Planning Status -- John 8. Any other Business REPORTS 1. Az track, antenna Report Az Track * Residual stress measurements were made on several wear plates on October 5. The ones in service had compressive stresses on the top and bottom surfaces, but were very shallow - only .001 to .002" deep. * Art, Dennis, and Bob visited a radar antenna under construction by RSI. It had a number of "improvements" that they've made since the GBT. Some may help us, but since it hasn't seen service yet, we are a little hesitant on some of them. * The 3 of us are going to SGH on 10/25 to discuss results of the Phase 3 work, and determine whether to continue that effort. The results to date have not helped our understanding. 2. Observing News This report covers the last two weeks. Over that time we supported 17 projects in 31 observing sessions for about 240 hours of observing. The rest of the telescope's time was devoted to maintenance (50 hrs), PTCS (24), Ka-band commisisong (16), software tests (5) and receiver checkouts (2). This is a much heavier load than usual. Lost time the first week was extrememly low (2 hrs or 1.5%) but this week we've had a large number of long-duration problems (31 hrs or 21%). The most significant sources of lost time were: Winds - 9.5 hrs Spectral Processor IF Draw - 5 hrs Spigot Mode 42 - 4 hrs LO1 Fiber - 3.7 hrs Spigot - Tick errors - 2.5 hrs GFM/IARDS/GO/Turtle - 2.3 hrs Converter Rack (failure to connect/rebooting) - 2.0 hrs Spectrometer Data Interrupt / Hung in running - 1.5 hrs Human - 0.7 hrs Antenna Trajectory - 0.5 hrs Prospero - 0.5 hrs Antenna reboot, rogue Scan Coordinator, Accessor, others - 1 hr Next weeks support load should be rather light due to a combination of a few projects, few observing sessions, and significant amounts of test time. RJM 3. Scheduling Status Last 2 Weeks ============= Observations for proposals GBT04C-009, GR024 , GBT04B-040, GBT04C-030, GBT03C-031, GBT02B-020, GBT04C-011, GBT04C-045, GBT04C-056, GBT02C-043, GBT02A-035, GBT04C-013, GBT04B-026, GBT04C-027, GBT04B-029, GBT04C-018, GBT04C-008 Completed proposals GBT04C-009, GBT04B-040, GBT02C-043, GBT04C-027 Next Week ========= Observations scheduled for GR024 PI Rajagopalan Ramachandran Measuring apparent angular size of pulsars behind HII regions GBT04C-030 [B] PI Wim van Driel A Search for Massive Low Surface Brightness Galaxies GBT02A-066 [P] PI David Hughes Breaking the Redshift Deadlock: The Spectroscopic Redshift of HDF850.1, the Brightest Sub-millimetre Source in the Hubble Deep Field GBT04A-003 [B] PI Steve Curran Highly Redshifted HI and OH Absorption in Red Quasars GBT04C-045 [B] PI Ingrid Stairs A Search for Pulsar Companions to New Low-Mass White Dwarfs GBT04C-008 [B] PI Yurii Pidopryhora Mapping the Galactic Halo HI: Evidence of Outflow from the Galactic Plane? GBT03B-019 PI Di Li The GBT HI Narrow Self Absorption Survey of Star Forming Regions Scheduled hours [backup] ======================== Category/Month-> October November December January Astronomy ~ 408 [095] 425 [296] 425 [194] 425 [312] Maintenance ~ 99 [034] 30 [051] 28 [077] 0 [136] Test & Comm ~ 221 [022] 212 [062] 187 [044] 249 [062] Shutdown ~ 0 36 36 0 Un-assigned ~ 17 18 69 70 Proposal Checkouts ================== Awaiting checkout - 0 Active checkout - 11 On Hold - 5 Schedule - 60 Completed - 235 Current backlog [hours prior to 04C*] = 1131 Total time to discharge [hours] = 2464 * Includes projects that are on hold for trimester 04C 4. Frontends, IFs, and Spectral Baselines Operational issues: A problem developed with the PF1 LO power sensor circuitry. It is not affecting data, so we will probably live with it until the next time the box is down. A problem developed with the GPIB link between gbtaio2 and LO1. A module replacement fixed the problem. The Ku-band refrigerator was changed this week due to irregular temperatures. Baselines: Finished going thru Converter Rack B modules to address the 60MHz ripple causes. Results not yet tested. Q-band: The final work to mount components should be finished today. Then some waveguide and coax interconnections and testing to be done. Ka Receiver: Commissioning continues. Issues are being addressed as needed. S-band: Cryo work is complete and thermal cals are underway. R. Norrod 10/22/2004 5. Spectrometer Status *****Operations***** Balser found both "large" and "small" steps in the autocorrelation functions of his data. Small lag steps were traced to a few chips on a correlator card. Further work needs to be done to determine why the steps were correlated with spectrometer phase (cal, sig/ref) while the correlator card knows nothing about phase. The card was replaced and this fixed the steps. It is quite sure that a LTA card SN7 causes the most of the big step in ACF. As we do not have spare LTA card which can work at 32MHZ to replace SN7, It still has to be in the system. But we will continue follow up the step, try to find out what exactly cause the step, and make sure that new LTA won't have the same problem at the same time test and debug the spare LTA on the test bench, hopefully can make at least one of them work well in 32MHZ. O'Neil has analyzed several other experiments and found lag steps in most of them. Project 4B26: There were severe problems with the spigot upgrade. Engineering tests included mode tests where pulses were shown to appear in the correct time slots. They also included acquisition of real data with two programs and subsequent analysis to assure that time tics were being properly transmitted and that calibrations, bandpasses and histograms looked normal. What were not tested were longer observations. These turned out to be a problem. Tic errors occurred a relatively short way into a normal observation. This was traced to the upgraded Xilinx personality. Time has been reserved for next week to attempt to understand and fix the problem. Project 4C45: The desired spigot mode, #42 (16-bit and 1024 channels), is apparently not working. The symptom is that the histogram of the zero lags has but a single value. This was true both on the sky and with a local noise source (to eliminate interference as the cause. Both modes 2 and 56 were tested and worked. However, mode 42 is the second most popular mode, so must be fixed asap. From an analysis of spectrometer data, Minter has found a convincing correlation between lag zero values and "DC" offset of the far out lags. This could be related to some baseline problems. O'Neil and Minter have planned additional tests. No progress has been made in trouble-shooting the 50 MHz, 3-level mode. There is no demand for this mode at this time, so this problem is not so critical. *****Development***** LTA replacement: The printed circuit design is being checked. Cross-Correlation Test Fixture: Only a few hours were dedicated to this project in the past few weeks. The printed circuit design for the output module is nearing completing. Spigot Mode Tests: Following upgrades to the correlator control cards, spigot cards, and spigot card Xilinx personalities, all spigot modes on the current mode description table (copies to be distributed at meeting) passed the engineering tests. *****Plans***** Test various upgrades to the spigot: Troubleshoot the new Xilinx problems. Astronomical test of upgraded Xilinx personalities Troubleshoot mode 42. Troubleshoot large and small lag steps. Continue LTA replacement and Cross-Correlation Text Fixture development. Rich and Holly 6. Software Status Single Dish Development IPT #102 - Friday, October 22, 2004 We are finishing week 3 of the seventh development cycle (C7) in 2004, which will run until mid-November. The Plan of Record is available from the wiki at Software.PlanOfRecordC72004. Great strides are being made with IDL work. Most of last week, the development group prepared for the IDL Design Workshop, which was held here in Green Bank on Friday, October 15. Ron, Bob Garwood, Jim Braatz and Paul Marganian gave presentations, and discussions were held with the non-NRAO collaborators who attended the meeting. The meeting was very productive and results are being collected. Development work continues on the data i/o modules, in particular the continuum modules which have just been started. Prototypes for the status screen are being reworked. The MR is written and awaiting approval, and all of the key values and issues associated with getting the values right have been identified. Melinda also made an improvement to Grail and altered the existing status code so that Grail requests are batched similar to how the config_tool does it. This should improve the performance of the status applications to the point where they can be used in a production capacity. In support of one of our site goals for 2004, simulators for the key parts of the control system are being brought together so that the SDD will have a reasonably comprehensive simulation capability. The MR has been completed and Mark has started the development work. Transporter reliability changes described in the last status report are still under investigation, and the most recent changes have been propagated to the new simulator for rigorous testing. This week's operational support included: * investigation of LO1 GPIB failures, antenna trajectory failures, and antennaCoordinator restart * restarting glishd in response to iards hang-ups * 3-window spectrometer slow speed sampler configuration mode fixed in response to Karen's observing 7. Project Planning Status October 12, 2004 Planning Meeting Minutes Rm 137 10:45 A.M. 0) Observer comments & operator log items resulting in lost time: Observer's comments received from: Alberto D. Bolatto Summary: Overall success of observations Very successful Observations will result in a journal paper Yes Description of success and problems: Telescope operated smoothly. We experienced only very minor problems and little observing time was lost. Data was converted using SDFITS and reduced in IDL as it came out of the telescope. Description of RFI environment: About half of the 800 MHz bandpass was lost to RFI. The RFI was highly variable, and changed from day to day. Clearly the RFI environment was better in the wee hours of the morning. The L band receiver bandpass was considerably cleaner. Perhaps only 20% was lost to interference. Operator's log comments Significant failures the past week stemmed from: Computing: Prospero failed, Naiad locked up. Software: Spectrometer Manager died, Spectral Processor hang, Receiver Managers stopped, LO1 failed, Transporter on earth and fire, config tool, antenna manager The problem of the Transporters is actively being worked. The receivers hanging is also being addressed. Electronics: Cryo compressor #3 losing pressure Telescope/Servo: HVAC failure in actuator room, EL brake CB message Other Problems from Observing Reports: F. Ghigo: Ka commissioning/test report KA-band receiver testing, concentrating on spectroscopy. In general, pretty sucessful. T. Minter: Measurements manager, Dynamic Corrections and PF1, D. Balser: Bad lags from spectrometer 1) Resource calendar schedule conflicts and discussions Norrod, Lacasse, and Stennes conflict on Wednesday. They will work it out. 2) Observing Schedule discussions None 3) GBT development planning We will have a 140 ft meeting this week to plan the potential 140 ft (now rechristened the 43 Meter.) A 3mm receiver meeting will be held next week to plan the resumption of work on this receiver. Phil brought up the fact that the Q band receiver checkout needs to be planned. 4) AOB The IDL development workshop is Friday, October 15th. The Antenna Azimuth Track review panel will meet early in December. October 18, 2004 Planning Meeting Agenda Rm 137 10:45 A.M. 0) Observer comments & operator log items resulting in lost time: Observer's comments received from: Operator's log comments Significant failures the past week stemmed from: Computing: Software: Antenna Manager, Spectrometer Manager, DCR Manager, Weather Manager, LO1 Manager, Converter rack manager, GO/IARDS/glishd (observer error?) Electronics: Spectral Processor IF system, spigot cards Telescope/Servo: Wind stows Other Problems from Observing Reports: R. Maddalena: GASP config tool problem, PF1 DCR data and 25 Hz cal 1) Resource calendar schedule conflicts and discussions Tuesday, Routine Maintenance and Program Checkouts conflict. Nathan and Karen have worked it out. 2) Observing Schedule discussions 3) GBT development planning JPL RSR backend Weather 3 replacement 4) AOB 8. Any other Business