GBT Operations and Commissioning Meeting 29 October 2004 AGENDA 1. Az track, antenna Report -- Bob 2. Observing News -- Ron 3. Scheduling Status -- Carl 4. Frontends, IFs, and Spectral Baselines -- Roger 5. Spectrometer Status -- Rich 6. Software Status -- Nicole 7. Project Planning Status -- John 8. Any other Business REPORTS 1. Az track, Antenna Report Az Track * Art, Dennis, and Bob went to SG&H's office in Waltham, MA to review results to date and set a course for remaining work. o The phase 3 results so far did show stresses that better mimic a wheel on a track, but their magnitudes were low. They did not show "dough rolling" effect of any substance as we had thought. We continue to research this in industry literature. o We reviewed our residual stress measurements and the results of the original plate metallurgy with them. We are going to authorize some additional calculations and review with an MIT metallurgist to incorporate these findings into the models, if possible (they would be additive, not necessarily requiring an additional run). o We are going to authorize SGH to do a model of a mitred joint using the new patch load and a modified model from Phase 2. This will give us a further basis for determining the amount of improvement with the welded joint and chevron-end wear plates. o We are going to authorize SGH to re-run a Phase 2 model without load in the holddown bolts. This will give us an idea of what a clip design, similiar to the one we saw in Texas, would experience. * We are going to pursue some metallurgy tests of the plates that haven't cracked. We have about 25% that haven't cracked. Antenna * We believe the two azimuth bearing seal failures are result of a lack of compression. We measured the first seal and it would have had 0.010" clearance, assuming the dimensions of the seal cavity are correct. We installed a replacement Tuesday with 0.015" compression to keep the seal locked and prevent movement. * We are performing some safety modifications to the telescope. A gate has been installed behind the receiver room to prevent a fall down the stairs. Other activities in progress are stiffening of the handrails, installation of additional tie-offs in the teepee for proper positioning when doing prime focus feed changes, and some safety netting above the handrail at the foot of the steep stairs going up to the top of the feed arm (protection below the handrail was done last year). -- RAA 2. Observing News This week we supported seven observing proposals in fifteen observing sessions, including a short VLB run. Other support activities were varied greatly and included PTCS test, Ka-band commissioning, calibration, API testing and 800-MHz receiver checkout. About 75 hours went to observing and 75 to tests, with the rest going to maintenance. Lost time this week was low and amounted to 4% of the time allotted to tests and observing. The major problems were: Turtle (mostly during test time) : 1.9 hrs Hardware Configuration/Human : 1.2 hrs Spectrometer : 0.8 hrs Az Brake Faults : 0.5 hrs Spectral Processor : 0.5 hrs Dynamic Corrections : 0.5 hrs Others : M&C testing, GO, ... : 0.7 hrs Average setup time was 40 minutes. Next week's support activities will include PTCS, Ka-band and Q-band tests. Observing support will be light since there's very few projects on the schedule, most of which have extended, contiguous hours. -- RJM 3. Scheduling Status Last Week ========= Observations for proposals GR024 , GBT04C-030, GBT02A-066, GBT04A-003, GBT04C-045, GBT04C-008, GBT03B-019 Completed proposals GR024, GBT04A-003, GBT04C-045, GBT03B-019 Next Week ========= Observations scheduled for GM055 PI Jon Marcaide Monitoring The Expansion Of Sn 1993j At 6 And 18 Cm 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 GBT04C-055 PI John Hewitt A Search for OH(4765 MHz) Maser Emission Associated with Supernova Remnant Masers using the GBT GBT04C-012 PI Jennifer Donovan Deep Searches for Young Pulsars in ``Shell'' Supernova Remnants GBT04B-028 [B] PI Scott Ransom Multi-Epoch Multi-Frequency Scintillation Velocity Measurements of the Double-Pulsar Binary J0737-3039 GBT04C-008 [B] PI Yurii Pidopryhora Mapping the Galactic Halo HI: Evidence of Outflow from the Galactic Plane? Scheduled hours [backup] ======================== Category/Month-> October November December January Astronomy ~ 421 [027] 424 [306] 422 [194] 433 [303] Maintenance ~ 116 30 [060] 28 [077] 0 [136] Test & Comm ~ 200 [004] 219 [064] 188 [044] 253 [058] Shutdown ~ 0 36 36 0 Un-assigned ~ 7 12 71 58 Proposal Checkouts ================== Awaiting checkout - 0 Active checkout - 11 On Hold - 5 Schedule - 57 Completed - 239 Current backlog [hours prior to 04C*] = 1107 Total time to discharge [hours] = 2427 * Includes projects that are on hold for trimester 04C -- RCB 4. Frontends, IFs, and Spectral Baselines Operational issues: Nothing unusual this week. Baselines: Nothing to report. Q-band: Testing is underway. The output noise spectrum is much improved although there are some gain dips Gary is trying to pinpoint. S-band: The receiver is ready to go back up next available Maintenance day. Tcals in linear pol have been measured; circular pol must be done on the telescope. Other: We had a kick-off meeting on restarting the 3mm receiver project. Mike Stennes is actively working on the project. R. Norrod 10/28/2004 5. Spectrometer Status Spectrometer Report 22 October - 28 October 2004 *****Operations***** GBT03B-019 Rcvr1_2 L(1.15-1.73 GHz) Oscillation was seen in some of the data. Changing to using 2 channels per bank instead of 4, took care of the lag problem. It's not clear whether this was a set up problem, interference or ?. Minter, O'Neil and Lacasse performed tests on the spectrometer to measure the high lag average level as a function of input power. Since high lags are pretty much uncorrelated, the average level is equivalent to a DC offset in the input. It was found that the average high lag level varied as a function of spectrometer input level. Moreover, at certain input levels, the average level is negative. A meeting to discuss the significance of this finding is planned. A fair amount of testing was performed to isolate the cause of "zero width" histograms in spigot mode 42. Two problems were uncovered. First, the executable in the spigot2 computer was an older version. Second the new firmware on the spigot card was associated with the problem. The problem was fixed by installing the latest software in spigot2 and going back to the old firmware on the spigot. Spent one and half days working on testing and fixing a spare LTA card. Now the spare LTA card, SN1, is put into the system to replace SN7 which sometimes gives big lag steps in the ACF. So far, SN1 seems work fine, but time will tell if SN1 really works better than SN7. *****Development***** LTA replacement: Continued checking and modifying the LTA PCB. Cross-Correlation Test Fixture: Only a few hours were dedicated to this project this week. The printed circuit design for the output module is nearing completion. Spigot: A FIFO was added to the output circuit of the spigot card and successfully tested. *****Plans***** Test new spigot firmware if errors are found and corrected Continue LTA replacement and Cross-Correlation Text Fixture development. -- Rich and Holly 6. Software Status Single Dish Development IPT #103 - Friday, October 29, 2004 We are finishing week 4 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. IDL work continued this week, as the I/O interface was refactored, performance issues were resolved, memory leaks were identified and fixed, and prototypes for the data model and code for basic continuum processing were completed. By the end of the cycle, the project scientist will be able to run his own tests using the new software. In an effort to make the Turtle observation management system available for use by all staff astronomers for evaluation, several updates were made this week to strengthen the reliability of the application. Startup is more reliable now, and messages are presented when monctrl@vortex is not in the gateway or if the user is trying to execute the program from a write-protected directory. The abort functionality has been improved and is now more stable. A "submit" button was added to the Edit panel so that you can now explicitly promote a script to the job queue. Items can also be removed from the job queue. Also, the difference between project IDs and data directories has been clarified in the latest changes, so you will no longer have to request a new project ID if you want your data written to a new directory, because you control your session ID (typically _01, _02) yourself. Finally, a "RestartTurtle" program was written for the operators to recover from problems, coordinating several steps that previously had to be done very carefully. Operators will be given training on Turtle, troubleshooting and recovery next Tuesday. A training session for astronomers will be scheduled as soon as reliability tests all pass, which could be early next week. Melinda has continued work this week on the status applications for upcoming pulsar observing runs, consolidating the presentation of some fields and continuing timing tests on the various aspects of pulling status information together. Also this week, Ray ported Grail (which now runs in production on Solaris) to Linux. The performance of the application was immediately improved. Although this must be rigorously tested over the next couple of weeks prior to the release, it is a very promising new development and Melinda is already testing out this version for optimal performance of the new status application. In the process of porting, Ray also set up Grail so that it can use manager-level security if and when we go that way, and dynamic strings are now supported (so anyone who has seen the problem where the source name gets truncated, this has been fixed). This week's operational support included: * A false "fatal" status on the antenna was investigated, but no resolution beyond restarting the antenna manager and antenna coordinator. * Paul responded to some issues with Antenna Characterization where cleo was reporting problems, but dynamic corrections continued to update. The investigation is still underway. * When antenna mode is changed, you now no longer have to restart grail, as this is handled by the system configuration file. This was patched in on Monday. -- NMR 7. Project Planning Status October 25, 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: None. Operator's log comments Significant failures the past week stemmed from: Computing: None Software: LO1 Manager, Spectrometer Manager failure, Config tool, spigot software problem, software testing, Turtle failures, Dynamic corrections not updating, Spectrometer serial line faults The LO1 bug fix concerning the application of doppler shifting to continuum observations will be scheduled for next cycle. It was pointed out that the Turtle programs are still experimental, and so any lost time should be accepted as a normal part of the test process, and people should read reports with that in mind. Electronics: LO1 power level dropouts, Spectrometer lag dropouts LO1 power level dropouts were traced to a bad GPIB controller. There have been reports of bad LO levels at PF1 when switching the cal at high frequencies, but this is a monitoring problem, and not an actual LO level problem. The spectrometer lag dropouts were found to be from a bad LTA card. The spare card is being tested and will be used to replace the bad card as soon as possible. Telescope/Servo: Az brake fault This will be checked to see if it is a repeating problem with the electronics, or if it is with a brake. Other Problems from Observing Reports: Frank Ghigo: VLBI at 300 MHz not completely successful. Some time was missed due to the VLBA station computer software failing, and the AZ brake fault. PF1 had funny system temperatures. Brian Mason: Ka band commissioning stuff [1] Resource calendar schedule conflicts and discussions None noted so far. Pete asked about switching around the maintenance days to accomodate a seal change. The seal is leaking badly. This was done, with maintenance split between Tuesday afternoon and Thursday morning. This allowed the observer to get his time, and the seal to be replaced at the earliest possible time. [2] Observing Schedule discussions Some backup and some good weather time is available over the weekend. [3] GBT development planning A meeting will be held soon to block out commissioning time requirements for trimester 05A (February through May) Cycle 8 planning meeting will be held November 9th, with all requests due in November 5th. Planning meetings for Cycle 1 of 2005 will be held in December before the holidays. Probably Tuesday December 21st. Requests will be due December 17th. [4] AOB -- JMF 8. Any other Business