GBT Operations & Commissioning Meeting
AGENDA
Activities List
-
- We are ready for Monday!
- SATCOM mobilized this week, bringing a laser tracker and putting it through it's paces, and checking our monuments. They are pleased with the results. Rental equipment has been arriving all week, and checkouts by SATCOM and our folks have been successful and continue today.
- We performed a grout trial on Wednesday to verify the flow of the grout around the studs and nuts on the bottom of the plate, and to train the field crew on the operation. This test was a big success.
- We also performed more tensioning tests, and familiarized the SATCOM crew with that operation as well.
- There is only minor activity today with equipment checkouts. No activity is planned this weekend.
- Monday will consist mostly of lockout and removal of the lower platform and stairs for our folks, and SATCOM will begin demolition early in the day. Continental will also mobilize their machining crew Monday.
We supported 18 projects in 35 observing sessions, including a VLB run. The telescope was scheduled for 12.8 hrs of PTCS tests and 8.5 hrs of maintenance. Lost time this week came from a much larger number of problems then is typical. 8.8 hrs was lost from 38 problems.
- Weather (1.9 hrs, 1.2% )
- Winds (3 instances) : 1.4 hrs
- Other : 0.5 hrs
- User Error (0.2 hrs)
- Astrid Script (2 instances) : 0.2 hrs
- Hardware configuration : 0.1 hrs
- Software/Hardware/Operations (6.9 hrs, 4.3%)
- Az Tachometer : 1.1 hrs
- Config-tool (2 instances) : 1.2 hrs
- Cryogenics - Compressor #3/C-band: 1.1 hrs
- Astrid (7 instances) : 0.8 hrs
- Optical Driver 5 : 0.6 hrs
- Spectral Processor (3 instances) : 0.4 hrs
- Az Transducer (2 instances) : 0.4 hrs
- GFM (4 instances) : 0.3 hrs
- Active Surface : 0.3 hrs
- Computing : 0.2 hrs
- Spigot Tick Error : 0.2 hrs
- Turret Lock : 0.1 hrs
- Other (M&C Change Optics, Az controller, Spectrometer, Scan Coord) : 0.17
It's the number of problems that's striking, not the severity.
Last Week
=========
Observations for proposals
GBT07A-041, GBT06C-051, GBT07A-098,
GBT07A-023, GBT07A-034, GBT07A-100,
GBT07A-058, GBT07A-037, GBT07A-015,
GBT06C-045, GBT07A-104, GBT07A-038,
GBT07A-016, GBT06C-003, GBT06B-015,
GBT07A-080, GBT06B-018, BB241
Completed proposals
GBT06C-051, GBT07A-038, GBT07A-080
Next Week
=========
Observations scheduled for **
GBT07A-053 [F ] Dunc Lorimer
A 350-MHz drift-scan survey for pulsars with the GBT
GBT07A-098 [F ] Fernando Camilo
Studying the magnetar XTE J1810-197
GBT06A-054 [F ] Paul Demorest
Long-term Precision Timing of Millisecond Pulsars
GBT07A-100 [ P ] Pat Thaddeus
Search for the anions C4H- and C8H- in TMC-1 and additional observations of C6H-
GBT07A-023 [ B] G. Welch
The First Survey of HI in a Volume-limited Sample of Elliptical Galaxies
GBT07A-101 [ P ] Clive Dickinson
Ka-band CCB high-resolution mapping of spinning
dust
GBT05B-011 [F ] Toney Minter
Using Pulsar HI Absorption to Determine the Distance to the Local Spiral Arm in the Second
Quadrant of the Galaxy
GBT03C-030 [F ] Jayaram Chengalur
Constraining the variation of fundamental constants using 18cm OH lines
GBT07A-058 [F ] Jane Greaves
Cyclotron emission asociated with exo-planets
GBT07A-037 [ B] Karen O'Neil
Further Observations of HI in Galaxies and Environments
GBT07A-016 [F ] Jennifer Donovan
How "Dry" Are Dry Mergers?
GBT06C-003 [ P ] Tony Remijan
Additional Transitions of Interstellar Methyl Isocyanate (CH3NCO)
GBT06B-015 [ P ] Larry Morgan
NH3 and CCS Mapping of Triggered Star Formation Regions
GBT06C-105 [ P ] Jeff Wagg
A confirmation of strong CO J=1-0 emission at z=5.2
BB231 [F ] Jim Braatz
The Megamaser Cosmology Project: Measuring Distances to NGC6323 and Mrk 1419
** Scheduled as F-ixed, P-rimary, B-ackup
Contact Information for 05/10/2007 - 05/24/2007
=======================================
Proposal PI Bands Email [NRAO contact]
---------- ------------------ ----- --------------------
GBT07A-053 Dunc Lorimer 3 Duncan.Lorimer@mail.wvu.edu [Toney Minter]
Scheduled hours [backup]
========================
Category/Month-> April May June July
Astronomy ~ 633 [029] 531 374 500
Maintenance ~ 62 213 347 203
Test & Comm ~ 26 0 0 42
Un-assigned ~ 0 0 0 0
Proposal Checkouts #[hrs]*
=========================
Awaiting checkout - 0[0]
Active checkout - 0[0]
On Hold - 12[341]
Schedule - 52[1478]
Completed - 474[6319]
* All but completed queue applies to GBT only proposals
Current backlog [hours prior to 07A*] = 871
[2005:405(16), 2006:461(29), 2007:5(1)]
Backlog includes 52 hrs of monitoring projects
175 hrs of vlbi projects
Total time to discharge [hours] = 6067
Includes 120 hours of monitoring after trimester 07A
3137 hours of Large proposals
970 hours of Track Refurbishment proposals
223 hours of VLBI proposals
* Includes projects that are on hold for trimester 07A
- Failed Compressor for C band during K band observing run due to mechanical failure of fan support.
- Replaced compressor with spare from cryogenics lab.
- 50 Mhz ripple reported on Optical Link 5 during K band observing.
- Swapped to Link 6 during observing; returned link 5 to health file.
- Found partially tightened connector; Tightened connector.
- Subsequent tests showed no hint of ripple.
- Feed plates located and ready to install for all receivers that are to be removed.
- C band design review
- Panel approved construction of remaining down converters.
- Two action items: RF to IF isolation was completed, RFI environment is to be measured.
- Housing sent to CV for gold plating.
Digital Group Status 21-APR-07 THRU 27-APR-07
***Operations, Problem Summary***
Active Surface Maintenance...
No work was done on the Active Surface this week.
Weather Stations, etc....
- It was discovered that two cups were missing from Weather 1's wind speed indicator. The cups were replaced, which fixed the problem.
- A question was raised by OPS regarding wind speed data from Weather 3. This will be checked using a hand-held anemometer at our next available opportunity.
- OPS also questioned whether the lightning detector at the warehouse is functioning properly. This will be checked out next week.
***Development***
Spectrometer LTA Re-design...
Bad lags have now been reduced and isolated only to odd-numbered integrations exceeding 30 seconds in duration, and only occurring in dynamic ram block #1. Another week or two of testing will be required to sort this out.
New Pulsar Backend...
No significant news to report.
ALMA...
On-going efforts are continuing fairly smoothly on the ALMA front.
***Plans***
- Continue daily check of Spectrometer exhaust fans...
- Continue testing the first three LTA FPGA Adapter PCBAs...
- Check out operational status of lightning detector at warehouse...
- Verify wind speed data from Weather 3 and repair if necessary...
- Continue ALMA efforts as required...
Randy
We had an intermittant hardware failure on the 45ft brake board. We believe we found it, shorting between traces on the pc card. Missed a couple days operation while investigating. There is also a temperature issue where the servo cabinet is getting warmer than we would like. Bill Radcliff is replacing some weak fans. We may need to better vent the dog house.
The 140ft declination brake pressures are measuring low with the new logging system. We intend to work with Preston Monday to determine the specifics, things are still safe.
Work is progressing on the GBT PLC Control system upgrade in the areas of printed circuit board designs, system layout, and ladder logic design. We have a preliminary design review scheduled for Tuesday of next week.
We took a half a day to scope out the feedarm cable upgrade on the GBT. Spreadsheets documenting the details have been created and we plan on nailing down all the specifics next week.
We have asked Reliance Electric to come inspect the GBT Az/El motors to help us determine which ones we need to have re-built over the summer. They also agreed to give us a quote to repair our failing tachometers.
We are in week four of the third development cycle of 2007 which can be viewed at PlanOfRecordC32007. We are scheduled for release on 16 May 2007.
Operational and user support was relatively light this week and included:
- Responded to report of Spectrometer generating repeated serial-line errors, cause was spectrometer had turned itself off.
- Observer's astrid lost connections to Grail and turtle, restarting astrid was insufficient to clear all problems, forced to restart turtle.
- Responded to report that the Spectral Processor was inoperative because Task Master could not restart processes.
Modification Requests:
- MRs ready for integration/regression testing:
- MRs ready for sponsor testing:
- MRs under development:
- SCCU Servo Changes (ModificationRequest1C806)
- Although the code is working, we have found that commanded velocity spikes occur during normal observing. To date this has not been a problem since the hardware filters out the spikes. However with the hardware modifications coupled with this MR, the spikes will corrupt the intended operation of the friction compensation. John is working on modeling a different methods of deriving the velocity commands.
- MRs under CCC review:
- MRs under sponsor review:
- Update Pointing/Focus code to Handle Old Data Sets (ModificationRequest3C207)
- MR written, with sponsor for review. Developing unit tests.
- MRs being written:
- Other Activities:
- Dynamic Scheduling - We are in the process of responding to comments received on the Overview. Melinda and Mark are completing work on Criteria II of Selection Rules and have 54 unit tests in place. They are placing Dana's required weather data into a database and have finished implementing Criteria III. They are now starting work on the observer's project view.
- Analysis of Trajectory Generation Problems - Joe is working on a document to summarize the investigations to date. Briefly, he's increased the command generation rate in the antenna and revised the velocity and acceleration generation to use a Savitsky-Golay differentiator. He has also located some sources of acceleration glitches, but has been unable to completely resolve them. He is now looking into what may be a much simpler method, documented by Garonski in a JPL report, which acts more like a filter than a trajectory planner. Joe thinks this style of jerk limiting is necessary, because it can be active 100% of the time, not just during slews.
- Find/Fix Command Stream Glitches - On hold pending trajectory generation problem analysis.
- Complete Pointing Processing Description Memo - No progress
- Complete Documentation of Cross-Polarization Changes - In progress.
- Evaluate GBT Data Handling Status & Future Options - In progress. Bob has been evaluating relevant technologies. He has been experimenting with two ways to possibly allow "IDL" to interact with Python - gdl (the gnu IDL) and pyIDL. pyIDL is very promising and Bob says that it works as advertised; he was able to involve GBTIDL from Python and found the process to be straightforward.
Last weeks power outage: The generator DID start up and work as it should. It appears there was just some confusion over which circuits were on the generator. This was probably compounded by the UPS failure in the equipment room. The failed UPS is scheduled for battery replacement Tues 1st May.
PTCS -- PTCS Team
- Astronomy
- The track map data obtained last week has been analyzed by Kim. The results look promising -- after processing and filtering the inclinometer data, the features seen in the forward and backward scans are consistent to < 0.5 arcsec. The expected 180 degree symmetry is seen in the pattern, and the orthogonally-mounted inclinometers give similar results when shifted by 90 degrees. The largest large-scale feature is a +/-6 arcsec deviation from the average. Small scale features are seen down to length scales of 25 cm on the track.
- We grabbed 4.5 hours of X-band all-sky pointing on Tuesday night. Kim is now combining these data with the other data taken during the past month to fit a new pointing model with track-dependent terms. At present, the rms of the new model measured over all of the data is 3" in azim, and 3.2" in elev, which is not much better than the current model. However there are some remaining mysteries in the data taken since August that could be due to a systematic error, particularly in the focus results. The integrity of the new pre-processing/fitting routines will be examined more next week.
- Engineering
- Working on PTCS Project Note on friction compensation and acceleration feedforward. This should be completed next week, and the modifications can be released and test on elevation over the summer. In August we will test and release the azimuth axis modifications.
- Signed final MR on accelerometer mods
MIT/LL 43m Project -- Glen
Our Ka-band commissioning memo is in first draft and will be released early next week.
-- CarlBignell - 26 Apr 2007
Revision r1.11 - 27 Apr 2007 - 13:31 GMT - AmyShelton
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