GBT Commissioning and Operations Meeting 31 October 2003 AGENDA 1. Az Track and Telescope Status -- Bob 2. Observing News -- Karen 3. Frontends, IFs, and Spectral Baselines -- Roger 4. Spectrometer Status -- Rich 5. Software Status -- Amy 6. Scheduling Status -- Carl 7. Project Planning Status -- John 8. Any other Business PRELIMINARY REPORTS 1. Az Track and Telescope Status Azimuth Track * We received a quotation from Gadsden Tool for 2 more spare plates out of 4140 material. They are working on a quotation for plates out of the other materials Dennis and I are interested in trying. * We have been delayed in making progress on the deflection measurements due to the servo system problems, but Tim is gettin back on that now. * SG&H has resolved some big model run time issues, and is back to work (with 2 GB of RAM!). We have scheduled a visit with them for 11/18 (Dennis, Art Symmes, and myself). Structural Defects/Repairs * Modjeski and Masters installed strain gauges on the elevation stub shaft assembly this week, and we successfully got data from 44 out of 45 gauges through the whole range of motion (with and without winds!) yesterday. Dr. Peter Keating will be analyzing the data and making recommendations in the next couple of weeks. * I also went over the other defects in the walkway and got his concurrence on the fixes in progress. Upper Elevator * The safety device was successfully installed and tested this week. The old device was set too high, resulting in excessive force during the sudden stops. The new device was set properly by the company technician. A new roller will be installed when it arrives, resulting in a short elevator outage. Azimuth Bearings * The new trial seals and lubricant will be installed on 11/4. -- RAA 2. Observing News GBT Observing Report, 23-30 Oct, 2003 Between early morning on the 23rd through evening on the 30th we ran 9 different astronomy projects, 2 commissioning projects, and the rest of the time went to maintenance. Of the 9 astronomy projects, 6 (approx 60 hours) were at K-band using the spectrometer, 2 (approx. 45 hours) were at l-band using the spectral processor, and 1 (12 hours) was at X-band with the VLBI system. Only minor problems were encountered during the observing: - The spectrometer falsely indicated a set-up problem, when it did not have one. This problem was unrepeatable when the software group tried to analyze it. - The k-band receiver reported slightly higher than expected temperatures on 25 Oct. - Spectrometer still takes a long time to stop a scan - The new configuration commands needed the "g.setup()" command to be run twice before the spectrometer would be set-up correctly. This bug has been found and fixed. The only project checkout was for 02C-43, using the K and X bands. No unexpected problems were encountered, although it was not possible to set up all four desired frequency bands at x-band due to missing the LO2 synthesizers. The checkout proceeded regardless (without any real loss). A quick look on my (Karen's) part indicated the baselines _should_ be stable enough over the desired 60s time for the project to be scheduled, however the data is now in the hands of the observer, who will determine if the baselines are stable enough for his project to go ahead. The last project which ran was a baseline checkout by Roger. I have no information on that. Detailed info on the astronomy projects is below: 02C-065, Braatz, Spectrometer, K-band [26] 03C-012, Braatz, Spectrometer, K-band [7] 02A-046, Braatz, Spectrometer, K-band [3] 02C-062, Modjaz, Spectrometer, K-band [Ghigo, 6] 02Z-063, Claussen, Spectrometer, K-band [Maddalena, 6] 03C-010, Sahai, Spectrometer, K-band [Maddalena, 13.5] 02A-069, Fisher, Spectral Proc., L-band [14.5] 03A-014, Lockman, Spectral Proc., L-band [31.5] U0003, Ulvestad, VLBI, X-band [Ghigo, 12] -Karen 3. Frontends, IFs, and Spectral Baselines The modifications to the Ku-band receiver required for the new cryogenic amplifiers are nearing completion. Target date to install the receiver is November 12. New cryo amps are now all in the Q-band and cold testing has resumed. Target date to install the receiver is November 11. Testing continues in an attempt to isolate the source of baseline structure on continuum sources, introduced near the spectrometer. We made careful gain measurements through the Analog Filter Rack Sampler/Filter modules, and made astronomical measurements for various clipper level settings. We also began additional RF tests of the sampler modules in the lab. I feel we are making progress, but there are no definitive results to report as yet. Field mods to the synthesizers used as the system LO2 are underway. These will make more output power available, which we expect will improve the gain stability of the converter modules. The rate the mods will be accomplished is set by access to Equipment Room equipment - essentially maintenance days only. Steve has done modeling of our microstrip to coax adapters using CST, discovering critical areas that can be improved. A new test fixture incorporating these factors is being designed for evaluation. -- RDN 10/31/2003 4. Spectrometer Status There have been a few complaints about needing to set the spectrometer up twice to get it to operate correctly. The software group looked through their code and found no significant problems. When doing hardware tests we will be more careful about documenting sequences of events that lead to failures. If this problem is in the firmware, it will take major changes in the firmware to fix it. In particular the protocol would have to be altered to provide some type of acknowledge after each command. A fair amount of time was spent on the high speed samplers this week. A decision was made to go with the simpler of two possible modifications. The simpler modification gives fairly consistent results from unit to unit and quite good performance (as shown last week). The more complex modification has the potential to improve performance, but the repeatability from unit to unit is not consistent. Four out of ten have been modified; the balance will be completed over the next few weeks. One of the main constraints is spectrometer availability. Also, some tests were run on the telescope and on the bench to see if the High Speed Samplers are contributing to the baseline problem. Roger and Rick will provide additional comments on this topic when the data is fully analyzed. The pulsar spigot is back in business. Problems with the system jumping out of sync after only a few seconds were traced to a new kernel that was installed with the new operating system on the spigot computer. A different kernel has reduced the frequency of sync errors to about one in 40 minutes. The basic problem appears to be that Linux is not a true real-time operating system, and it possible for the data acquisition task to be pre-empted on occasion. Data are stored such that all the data that were sent before the error occurred are usable. Additional improvements were made to the scripts used to set up for spigot observations. Work on the LTA redesign continues. The FPGA design should be complete by the end of the year. At that time, design of the rest of the board will start. -- Rich and Holly 5. Software Status Single Dish Development IPT #57 - Friday, October 30, 2003 Today ends week 4 of 6 in the current development cycle, which is the 8th cycle in 2003. The Plan of Record for the current development cycle is available from the wiki at Software.PlanOfRecordC82003 along with the most up-to-date status information. Frank Ghigo presented a talk on the beta Configuration Tool this week to Green Bank staff. Users are encouraged to visit the wiki and look under Knowledge.HowToConfigureTheGbt to find up-to-date information on how to use the beta Configuration Tool to configure an observation. Please send all feedback on the tool to Melinda Mello. The new antenna controller ran without error under simulation for 722 'pointing run' style scans. We are ready to support on sky tests with the new controller next week. We have started our investigation into using Class in Green Bank. The information on this project can be found on the wiki at Data.UsingClass. Work continues on SDFITS. Our focus is solely on the Spectrometer at the moment. Other backends will follow when it is deemed that sufficient progress has been made with the Spectrometer. We hope to have implemented substantial improvements in SDFITS output for the digital continuum receiver and the spectral processor by end of cycle as well. Further information on this project can be found on the wiki at Data.SdfitsBetaStatus. Incremental work was completed on Python tasks for PTCS, making the SOAP interface to M&C more complete, SDFITS generation, and prototype applications for the "new GO" which will be unveiled during the next cycle for initial community review. There was no significant operational support this week. -- AS 6. Scheduling Status Last Week ======== Observations for: GBT02C-062, GBT02C-054, GBT02C-065, GBT02A-063, GBT02A-046, GBT03C-010, GBT03A-014, GU003, GBT02A-031 Completed: GBT02C-062, GBT03C-010 October ====== Scheduled hours [backup] Astronomy ~ 355 [4.5] Maintenance ~ 133 Tests & Comm ~ 262 November ======= Scheduled hours [backup] Astronomy ~ 297 [134] Maintenance ~ 100 Tests & Comm ~ 288 [62] Shutdown ~ 36 December ======= Scheduled hours [backup] Astronomy ~ 199 [37] Maintenance ~ 111 Tests & Comm ~ 198 [24] Shutdown ~ 36 Un assigned ~ 201 -- RCB 7. Project Planning Status October 26th Planning Meeting Minutes Rm 241 10:00 A.M. [0] Observer comments GBT Observing Checkout: Jon Swift's Ammonia towards Taurus Molecular Cloud and: Wendy Lane's High Redshift Neutral Hydrogen Absorption Both projects can be scheduled. Wendy Lane's project needs software support for flagging the RFI-laden data. >From Ron: I helped Al Wootten and Kevin Marvil with their water maser project Tuesday night. Even though the weather wasn't the greatest, I think they went away happy with the quality of their data. Just a couple of bumps as we tried to set up the system. >From Jim: Some comments on observing project 2A46 and 2C65 on 25 October, at K-band (18-22 GHz): RECEIVER: Given the clear, cold weather, I was anticipating excellent Tsys. However it has been ~ 20K higher than I expected. CONFIG TOOL: This has been working wonderfully. SPECTROMETER: The reliability has been perfect. The only issue is that it seems to be taking a long time in "Stopping". {N.B. "a long time" is 5 seconds. This is consistent with what we expect, i.e. there is nothing broken, but it may need to be sped up if it becomes a big source of delay.} GO_LITE: A few issues here. Jim will work on it with Paul. CLEO: Please add ambient temperature and Y-focus values to the status display. IARDS: Iards is no longer being developed, and it cannot handle certain aspects of K-band observing. Specifically, TP observations using Nod are not calibrated in GOspec, and the bad channel in the 18-22 GHz RX is not ignored during focus. I've written some personal replacements (i.e. hacks) for GOspec and GOfocus to handle these situations. If you are observing or supporting K-band, I can fill you in. [1] Resource calendar schedule conflicts and discussion Nothing scheduled for next week. Elevator repairs moved to next week. Jason and harry's fix to TS #7 is in negotiations with the contractor on the elevation axle strain gauge tests. Track deflection measurements will be done next week. [2] October Observing Schedule discussions Some time is available this week due to K band and Q band troubles. [3] November Observing Schedule discussions We have decided to pull K band off mid-november for repairs. The observing schedule has been modified to reflect this. [4] GBT development planning Staffing Spreadsheet discussion We are developing a spreadsheet to pinpoint the hot spots of shortages in various disciplines. This will help us possibly level out the loads, or lobby for additional resources. It is clear that all divisions are fully loaded, with some considerably overloaded. [5] AOB Bob asked Phil about the AUI board meeting. Phil replied that the GBT presentation was well received, and only a few questions were asked. Phil showed our progress on getting additional observing time scheduled, and our progress to date on several software issues. -- JF 8. Any other Business