GBT Operations & Commissioning Meeting
AGENDA
Activities List
-
- We expect another shipment of base plates on Tuesday of next week, as well as a shipment of Wear plates.
- A bolt on the track failed, popped up as a wheel went by, and jammed against a track wiper and tore it off Tuesday. This was repaired Tuesday afternoon. Nothing was run over by a wheel.
- Several of us inspected an indication in a weld on the 140'. Our unanimous opinion is that it was a tear caused by freezing of trapped water. It is not a load bearing weld. It will be repaired and provision made to allow water to drain.
We supported 20 projects in 40 observing sessions. The telescope was scheduled for 12 hrs of PTCS tests, 8.5 hrs of maintenance, 4 hrs of M&C tests, and 3 hrs of C-band baseline tests.
Lost time came from a number of sources:
- Observer Errors (1.3 hrs, 0.8%)
- Inexperienced remote observer/Scheduling block problem (2 instances) : 0.5 hrs
- Project scheduled at wrong LST : 0.7 hrs
- Weather (6.4 hrs, 4.1%)
- Snow (5 instances) : 5.4 hrs
- Winds (3 instances) : 1.0 hrs
- Hardware/Software/Operations (7.1 hrs, 4.5%)
- Broken Track Scraper : 3.5 hrs
- PF Boom/Limit Switch (3 instances) : 1.5 hrs
- Astrid Lockups (5 instances) : 1.2 hrs
- Az transducer : 0.4 hrs
- Astrid database : 0.2 hrs
- Operator set wrong Az wrap : 0.2 hrs
In the last M&C release, a number of Astrid/GFM problems were solved. I have compared the lost time pre and post the release in the hope of seeing a reduction of lost time. Time lost to GFM software problems have almost all been eliminated. However, lost time due to Astrid problems have actually increased (0.3 hrs/week for 6 weeks before the release, 0.6 hrs/week after) and the number of instances per week (3) is about the same. Since I'm dealing with a small number of instances, I cannot say whether the increase is significant.
The observer's problem with a wrong LST came about because a high frequency observer did not inform us of whether they would use some excellent high-frequency weather. We tried to find a high frequency project that could use the time but the observer didn't realize that the LST was not appropriate for their object. As fast as we could, we switched to a PTCS pointing project.
Scott may want to talk to Paolo Freire concerning his observing scripts from last night. DJ and I spent about an hour trying to work through a number of issues.
Last 2 Weeks
=============
Observations for proposals
GBT07A-030, GBT07A-098, GBT07A-034,
GBT07A-012, GBT07A-089, GBT06B-032,
GBT06B-044, GBT05B-021, GBT06B-033,
GBT04C-031, GBT07A-048, GBT04A-001,
GBT07A-015, GBT06C-013, GBT07A-104,
GBT06B-014, GT007 , GBT06C-058,
BB248 , GBT07A-039, GBT06A-017,
GBT07A-019, GBT07A-080, GBT06C-017,
GBT05C-017, GBT06C-029, GBT07A-093,
GBT07A-072
Completed proposals
GBT07A-048, GT007, GBT05C-017
GBT06C-058, BB248, GBT07A-019,
GBT06C-017
Next Week
=========
Observations scheduled for **
GBT07A-030 [ P ] Brian Mason
A Search for Polarized, Anomalous Microwave
Emission from Lynds 1622 - copy
GBT07A-031 [ P ] Jim Braatz
The Megamaser Cosmology Project: Accelerations in
Maser Disks
GBT07A-098 [FPB] Fernando Camilo
Studying the magnetar XTE J1810-197
GBT06C-052 [ B] Scott Ransom
Continued Timing of the Binary and Millisecond
Pulsars in NGC6440 and NGC6441
GBT06A-054 [F B] Paul Demorest
Long-term Precision Timing of Millisecond Pulsars
GBT07A-012 [ P ] Mousumi Das
Searching for Water Masers in the AGN of Giant
Low Surface Brightness Galaxies
GBT07A-034 [ P ] Jim Braatz
The Megamaser Cosmology Project: A Survey for H2O
Masers in SDSS and 2MRS AGNs
GBT04C-031 [ P ] Paul Kondratko
Monitoring of Five NGC4258-like Water Megamasers
Discovered with the GBT and the DSN
GBT06A-068 [ P ] Yancy Shirley
The Kinematical and Chemical Structure of
Pre-protostellar Cores
GBT05C-032 [ P ] Yancy Shirley
Tracing Protostellar Mass During Star Formation
with 7mm and 9mm Continuum
GBT04A-001 [ P ] Paul VandenBout
Q-Band CO Observations
GBT06C-035 [ P ] Jim Braatz
The Megamaser Cosmology Project: A Survey for H2O
Maser Disks in SDSS AGNs
GBT07A-104 [F B] Peter Martin
The Spider's Web from Ursa Major to Polaris
GBT06C-003 [ P ] Tony Remijan
Additional Transitions of Interstellar Methyl
Isocyanate (CH3NCO)
GBT07A-039 [ B] Rick Fisher
Bulk Motions of Filaments in the Local Universe
BB247 [F ] Michael Busch
Radar Interferometric Imaging of Near-Earth
Asteroid VV2
GBT06B-018 [ B] Michael Kramer
Timing and General Relativity in the Double
Pulsar System
GBT06C-029 [F ] Sanjay Bhatnagar
GBT 330 MHz Survey of the Inner Galactic Plane
GBT07A-093 [ B] Sanchayeeta Borthakur
Diffuse Intragroup Medium: Evolution and
Connection to Large Scale Structures
** Scheduled as F-ixed, P-rimary, B-ackup
Contact Information for 04/05/2007 - 04/19/2007
=======================================
Proposal PI Bands Email [NRAO contact]
---------- ------------------ ----- --------------------
GBT07A-041 Antonio Crapsi K crapsi@strw.leidenuniv.nl [Jim Braatz]
GBT07A-074 Jack Hewitt X j-hewitt@northwestern.edu [Ron Maddalena]
GBT07A-042 Andrea Tarchi K a.tarchi@ira.inaf.it [Jim Braatz]
GBT07A-031 Jim Braatz K jbraatz@nrao.edu [Jim Braatz]
GBT06C-051 Lincoln Greenhill K greenhill@cfa.harvard.edu [Jim Braatz]
GBT07A-021 Arthur Wolfe 8 art@kingpin.ucsd.edu [Toney Minter]
GBT07A-098 Fernando Camilo S fernando@astro.columbia.edu [Scott Ransom]
GBT07A-089 Fernando Camilo 8 fernando@astro.columbia.edu [Scott Ransom]
GBT06B-032 Steve Begin S sbegin@physics.ubc.ca [Scott Ransom]
GBT07A-100 Pat Thaddeus K pthaddeus@cfa.harvard.edu [Frank Ghigo]
GBT07A-034 Jim Braatz K jbraatz@nrao.edu [Jim Braatz]
GBT06A-033 Howard Bond Q bond@stsci.edu [Ron Maddalena]
GBT06B-044 Robert Ferdman L ferdman@phas.ubc.ca [Scott Ransom]
GBT06B-033 Jason Hessels 8 jhessels@science.uva.nl [Scott Ransom]
GBT06C-045 David Champion S champion@physics.mcgill.ca [Scott Ransom]
GBT02A-054 Ingrid Stairs L istairs@astro.ubc.ca [Scott Ransom]
GBT06C-056 Pat Thaddeus U pthaddeus@cfa.harvard.edu [Ron Maddalena]
GBT07A-016 Jennifer Donovan L jen@astro.columbia.edu [Frank Ghigo]
GBT06C-003 Tony Remijan K aremijan@nrao.edu [Larry Morgan]
GBT06B-037 Joel Weisberg L jweisber@carleton.edu [Toney Minter]
GBT06C-048 Nissim Kanekar 8 nkanekar@nrao.edu [Toney Minter]
GBT06B-028 Ingrid Stairs L istairs@astro.ubc.ca [Scott Ransom]
GBT06C-105 Jeff Wagg K jwagg@nrao.edu []
GBT06B-018 Michael Kramer 8 mkramer@jb.man.ac.uk [Scott Ransom]
BB231 Jim Braatz K jbraatz@nrao.edu []
GBT07A-094 Scott Ransom S sransom@nrao.edu [Scott Ransom]
GBT07A-061 Rachel Osten S rosten@astro.umd.edu [Scott Ransom]
GBT07A-040 Larry Weintraub B lcw@astro.caltech.edu [Brian Mason]
Scheduled hours [backup]
========================
Category/Month-> March April
Astronomy ~ 628 [159] 589 [362]
Maintenance ~ 64 32 [051]
Test & Comm ~ 59 [003] 42 [008]
Shutdown ~ 0 17
Un-assigned ~ 0 41
Proposal Checkouts #[hrs]*
=========================
Awaiting checkout - 0[0]
Active checkout - 0[0]
On Hold - 14[358]
Schedule - 84[1965]
Completed - 440[6239]
* All but completed queue applies to GBT only proposals
Current backlog [hours prior to 07A*] = 1192
[2002:12(1), 2003:3(1), 2004:81(9), 2005:405(16), 2006:686(40), 2007:5(1)]
Backlog includes 82 hrs of monitoring projects
223 hrs of vlbi projects
Total time to discharge [hours] = 5788
Includes 152 hours of monitoring after trimester 07A
3137 hours of Large proposals
770 hours of Track Refurbishment proposals
283 hours of VLBI proposals
* Includes projects that are on hold for trimester 07A
Component swaps on the X-band LCP channel seem to have ended the dropouts previously reported. But, we can't be certain yet because the problem was so intermittent.
New, expanded range power samplers have been installed in Converter
Modules 4, 8, 11 and 15.
The previous power samplers presented a voltage over the range of
0.0-10.0 volts which corresponded to a power range of 20 dB. The new
power samplers present the same 0.0-10.0 volts but this now corresponds
to a power range of over 60 dB with 10.0 volts corresponding to about
the same power level as with the previous samplers.
Tests show that with the 800 MHz band pass filter switched in and with
about one volt indicated on the Analog Filter modules the Converter
Module samplers indicate about 2.5 volts, so don't be alarmed if you
balance the system for one volt at the Filter Rack and find the
Converter Module samplers no longer read zero! Observers using back
ends fed directly from the Converter Rack should find some utility in
the new power samplers as their signal levels should no longer be below
the lower threshold of the power samplers.
Please note that these power samplers have not been extensively tested
with regard to long term stability or repeatability and should not be
the sole source relied upon for research grade data.
Over the next couple weeks the remaining twelve Converter Modules will
be updated with new power samplers on maintenance days, further
announcements will be made as modules are updated.
Assembly of the first C-band integrated assembly nears completion; wirebonding of interconnects will follow next week.
It looks like changes need to be done in the 43m frequency converter and system monitor system to allow accurate Tsys measurements. The problem is still being scoped out.
Digital Group Status 17-MAR-07 THRU 23-MAR-07
***Operations, Problem Summary***
No problems to report this week.
Active Surface Maintenance...
No work was done on the active surface this week.
***Development***
Spectrometer LTA Re-design...
All parts, including the circuit boards, have now been received. At this point, the plan is to build the first article and begin testing early next week.
New Pulsar Backend...
- We now have a CASPER test suite running on Don Backer's loaner IBOB.
- A VNC/telecon session has been arranged for Friday afternoon during which Aaron Parsons (from CASPER) will interactively assist us with our preliminary design, toolflow, etc. The expected outcome of this session is for us to come away with a clear understanding of the PFB (poly phase filter bank) and FFT blocks which are crucial to our design. In addition, with Aaron's assistance, we hope to complete, install, and test a simplified proof-of-concept design on Don Backer's IBOB.
PTCS...
- A spare inclinometer and concentrator have been set up in the Digital Lab and turned over to Joe Brandt for testing.
- Re-work on the GDAQ firmware which reads accelerometers has begun. This effort seeks to eliminate spurious self-resets, and is similar to the work done for the Quadrant Detector.
ALMA...
On-going efforts are continuing fairly smoothly on the ALMA front.
***Plans***
- Build and test the first article LTA FPGA Adapter PCBA...
- Continue accelerometer GDAQ firmware upgrades...
- Get a proof-of-concept design running on Don Backer's IBOB...
- Continue ALMA efforts as required...
Randy
We are in week five of the second development cycle of 2007 which can be viewed at PlanOfRecordC22007. Our next release is scheduled on 28 March 2007. We had two integration tests this week. The first was very successful and the second is ongoing as I write this report. The test reports are available at: http://wiki.gb.nrao.edu/bin/view/Software/SoftwareReportCentral_IntegrationRegressionTestingReports
Operational and user support was relatively light this week.
Modification Requests:
- MRs ready for integration/regression testing:
- MRs ready for sponsor testing:
- Develop New Pointing Pre-Processing Application (ModificationRequest5C706)
- Sponsor testing continues with Frank and Kim. Updated Design section of MR. Correcting deficiency identified in sponsor testing.
- Extract Sampler Information from Log Files & Create Antenna Characterization Database (ModificationRequest3C107)
- PTCS group testing integration version. A couple of extra requirements have been mentioned, but not yet implemented.
- 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 being written:
- Fix Inclinometer Data Collection Problems (ModificationRequest1C207)
- Joe is in the process of integrating the new parallel data acquisition code into the Inclinometer Manager.
- Create Pyrgeometer Manager (ModificationRequest2C22007?)
- We have started looking at this, but the inclinometer work is the #1 PTCS priority.
- Update Pointing/Focus code to Handle Old Data Sets (ModificationRequest3C207)
- Source of issue located in code / old data - "beam C vs. beam 1" anomaly. Developing an extension of the simple workaround (C=1) that correctly makes this substitution when appropriate (it's an incorrect subst. in some instances).
- Modify Peak Finding Algorithm for Pointing/Focus Code (ModificationRequest4C207)
- Testing sponsor-suggested algorithm for finding signal peak.
- Other Activities:
- Dynamic Scheduling - We are in the process of responding to comments received on the Overview. Melinda and Mark are working on implementing Selection Criteria I rules.
- Complete Pointing Processing Description Memo - No progress
- Complete Documentation of Cross-Polarization Changes - In progress
- Evaluate GBT Data Handling Status & Future Options - In progress
Nothing to report.
PTCS -- PTCS Team
- Engineering work: Nothing new to report
- Astronomy work:
- All-sky pointing run was obtained on Monday morning March 19, with improved inclinometry datastream
- Next run is next week
Thanks to a successful testing session 2 weeks ago with Randy, I figured out one of the big problems with the 2048-lag 8-bit modes of the Spigot. Turns out that Ray Escoffier's documentation on how to reorder the data from the Spigot was correct (I should probably not be surprised). The problem was that we were using the wrong byte-ordering in the de-coding and had lags that were supposed to be most-significant bytes attributed to lags that were supposed to be least-significant bytes from the 16 bit words output by the Spigot. Was a total pain in the butt figuring this out.
Unfortunately, there is still at least one big issue with these modes. And that is that the calibration does not work. Ryan will be working on that over the next 2 weeks while I'm in Thailand. Bottom line is that things are looking good for these modes for summer use in the drift scan searches.
MIT/LL 43m Project -- Glen
- Pretty good week of spacecraft tracking.
- Steve W. has been looking into 43m RF/IF connection to Jansky Lab. Needs some modifications.
- Finding system temperature about 80 K between 1.5 and 3.0 GHz.
- MIT/LL Group returning next monday to install 0.15 to 1.7 GHz feed.
-- RichardPrestage - 22 Mar 2007
Revision r1.12 - 23 Mar 2007 - 12:01 GMT - ToddHunter
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