GBT Operations & Commissioning Meeting
AGENDA
Activities List
-
- We made QA checks on 5 of the first 13 wear plates. No systematic errors.
- 10 more plates will ship on Monday.
- 1st base plate and lifting gear to ship 3/12. A crane is scheduled to arrive 3/13 to off load the material.
- We checked spare 45' brakes, and will also check the ones on the elevation drives.
- Dennis and I did a design check of the electronics lab hoist and will re-rate it for 1500 lbs.
A very busy week for scientific support. The telescope was scheduled for 16 projects in 33 observing sessions, incluing a VLB run. 14.25 hrs for maintenance, 12 hrs for PTCS tests, and 3/4 hrs for receiver checkout.
The weather again dominated our lost time, although 6 of the 14 operator shifts didn't loose any time. The causes of lost time were:
- Weather (26.1 hrs, 16.8%)
- Winds (9 instances) : 4.3 hrs
- Snow/Ice : 15.7 hrs
- Snow/Ice removal (3 instances) : 5.8 hrs
- Hardware/Software/Operational (6.7 hrs, 4.3%)
- Active Surface Power Supply : 2.3 hrs
- L-Band Cable : 1.5 hrs
- X-Band Pwr Jumps : 1.0 hrs
- LO1 : 0.9 hrs
- Turtle/Grail : 0.6 hrs
- Az Motor : 0.2 hrs
- VNC : 0.2 hrs
(Note that some of these numbers may not be right -- the resource calendar/opslogs was down tonight so I had to use the originals of the operator logs). Because of the way the storm started off with ice, and that a significant problem is snow melting onto the receivers, there was really no way to prevent much of the lost time due to ice removal. The LO1 problem was 'fixed' by retyping by hand the rest frequency into CLEO.
Last Week
=========
Observations for proposals
GBT07A-030, GBT07A-063, GBT07A-010,
GBT07A-098, GBT06C-052, GBT06A-054,
GBT07A-034, GBT06A-056, GBT07A-036,
GBT07A-015, BC162 , GBT07A-104,
GBT07A-039, GBT04B-014, GBT07A-080,
GBT05C-017, GBT07A-050
Completed proposals
GBT07A-036, BC162
Next Week
=========
Observations scheduled for **
GBT07A-030 [ P ] Brian Mason
A Search for Polarized, Anomalous Microwave
Emission from Lynds 1622 - copy
GBT07A-042 [ P ] Andrea Tarchi
H2O versus continuum in the nucleus of the
megamaser galaxy 3C403
GBT06C-051 [ P ] Lincoln Greenhill
Monitoring 2 NGC4258-like Masers: Measurement of
Distances / Constraint of LCDM
GBT07A-098 [FPB] Fernando Camilo
Studying the magnetar XTE J1810-197
GBT07A-010 [F ] Bob Mutel
A Search for Narrow-Band Stellar Radio Bursts
Associated With CMI Emission
GBT06B-043 [ P ] Laurent Pagani
Depletion of heavy molecules in pre-stellar cores
GBT04C-031 [ P ] Paul Kondratko
Monitoring of Five NGC4258-like Water Megamasers
Discovered with the GBT and the DSN
GBT07A-015 [FPB] Jeff Mangum
Formaldehyde Densitometry of External Galaxies
GBT06C-045 [F ] David Champion
A Search for Radio Emission from Magnetars after
Outburst
GBT07A-039 [F B] Rick Fisher
Bulk Motions of Filaments in the Local Unverse
GBT06A-017 [ P ] Jeremy Lim
Molecular Gas in Infrared-Luminous Galaxies at
Intermediate Redshifts
GBT04B-014 [ P ] Paul Kondratko
Anchoring the Extragalactic Distance Scale
GBT06C-017 [ P ] Miles Blanton
Mapping the Galactic Center Lobe
GBT06C-018 [ B] Ingrid Stairs
Continued timing of a highly relativistic binary
pulsar system
GBT03C-028 [ P ] Fabian Walter
The Molecular Gas Content in z>6 Quasars: Probing
the End of Cosmic Reionization
GBT07A-072 [ B] Lisa Wei
Gas Reservoirs in Blue-Sequence Early-Type
Galaxies
** Scheduled as F-ixed, P-rimary, B-ackup
Contact Information for 03/15/2007 - 03/29/2007
=======================================
Proposal PI Bands Email [NRAO contact]
---------- ------------------ ----- --------------------
GBT07A-030 Brian Mason X bmason@nrao.edu [Brian Mason]
GBT07A-031 Jim Braatz K jbraatz@nrao.edu [Jim Braatz]
GBT07A-098 Fernando Camilo S fernando@astro.columbia.edu [Scott Ransom]
GBT06C-052 Scott Ransom S sransom@nrao.edu [Scott Ransom]
GBT06A-054 Paul Demorest L demorest@astron.berkeley.edu [Scott Ransom]
GBT07A-034 Jim Braatz K jbraatz@nrao.edu [Jim Braatz]
GBT07A-012 Mousumi Das K mousumi@rri.res.in [Larry Morgan]
GBT06B-044 Robert Ferdman L ferdman@phas.ubc.ca [Scott Ransom]
GBT04C-031 Paul Kondratko K pkondratko@cfa.harvard.edu [Jim Braatz]
GBT06A-068 Yancy Shirley K yshirley@as.arizona.edu [Toney Minter]
GBT05C-032 Yancy Shirley BQ yshirley@as.arizona.edu [Ron Maddalena]
GBT04A-001 Paul VandenBout Q pvandenb@nrao.edu [Ron Maddalena]
GBT07A-048 Larry Rudnick L larry@astro.umn.edu [Toney Minter]
GBT07A-015 Jeff Mangum C jmangum@nrao.edu [Frank Ghigo]
GBT06C-035 Jim Braatz K jbraatz@nrao.edu [Jim Braatz]
GBT07A-104 Peter Martin L pgmartin@cita.utoronto.ca [Jay Lockman]
GBT06B-014 Paulo Freire 3 pfreire@naic.edu [Scott Ransom]
GBT06C-003 Tony Remijan K aremijan@nrao.edu [Larry Morgan]
GBT07A-039 Rick Fisher L rfisher@nrao.edu [Frank Ghigo]
BB247 Michael Busch X busch@caltech.edu []
GBT06A-017 Jeremy Lim Q jlim@asiaa.sinica.edu.tw [Dana Balser]
GBT07A-019 Tom Maccarone 3 tjm@astro.soton.ac.uk [Scott Ransom]
GBT06B-018 Michael Kramer L mkramer@jb.man.ac.uk [Scott Ransom]
GBT07A-080 Maura McLaughlin 3 maura.mclaughlin@mail.wvu.edu [Scott Ransom]
GBT05C-017 Anish Roshi B anish@rri.res.in [Dana Balser]
GBT06C-029 Sanjay Bhatnagar 3 sbhatnag@nrao.edu [Glen Langston]
GBT07A-093 Sanchayeeta Bortha L sanch@fcrao1.astro.umass.edu [Frank Ghigo]
Scheduled hours [backup]
========================
Category/Month-> March April
Astronomy ~ 631 [527] 589 [362]
Maintenance ~ 45 [050] 32 [051]
Test & Comm ~ 66 [025] 42 [008]
Shutdown ~ 0 17
Un-assigned ~ 4 41
Proposal Checkouts #[hrs]*
=========================
Awaiting checkout - 0[0]
Active checkout - 0[0]
On Hold - 14[358]
Schedule - 90[2276]
Completed - 434[6250]
* All but completed queue applies to GBT only proposals
Current backlog [hours prior to 07A*] = 1290
[2002:12(1), 2003:12(1), 2004:103(9), 2005:407(17), 2006:751(44), 2007:5(1)]
Backlog includes 82 hrs of monitoring projects
223 hrs of vlbi projects
Total time to discharge [hours] = 4517
Includes 152 hours of monitoring after trimester 07A
1545 hours of Large proposals
770 hours of Track Refurbishment proposals
297 hours of VLBI proposals
* Includes projects that are on hold for trimester 07A
Maintenance day tests to investigate a reported instability in one L-band
receiver channel continued; data is still being analyzed. Toney is also
working with the observers to ensure there really is a receiver problem.
Toney reported that the phase time was variable during the observations,
which is not expected.
One channel of the X-band front-end (LCP) showed some gain instabilities
this week. Maintenance day testing did not isolate the cause, although all
connections were loosened and re-torqued. Afterwards, the data was stable
for at least a half hour, but we don't know if the problem is really fixed.
Production assembly of the upgraded detector boards for the Converter
Modules started this week, when a tech became available.
The first housing for the C-band integrated assembly was sent off to be
plated, after successful trial fits of the internal components.
Digital Group Status 24-FEB-07 THRU 02-MAR-07
***Operations, Problem Summary***
- The daily temp sensor email flagged gbtts6_2004 (backup structure 36+000) as being unacceptably noisy. This unit was replaced with a new sensor which is now working properly. The failed unit is undergoing a post-mortem in the lab in an effort to find out what went wrong.
- On 27-FEB-07 Jason and J.D. were called in at around 7:00 AM due to about 550 disabled actuators on the Active Surface. Further investigation uncovered a failed capacitor in a Transnet power supply. The power supply was repaired which brought all 550 actuators back on line. Six new capacitors have been ordered to cover such future failures.
Active Surface Maintenance...
(See above...)
***Development***
Spectrometer LTA Re-design...
All parts (including circuit boards) are now on order with expected deliveries in about two weeks. The plan is to build three new adapter boards, install them in a spare LTA, conduct bench tests in the test fixture, then move this LTA into the Lab Spectrometer for longer-term testing. Following this, the remaining LTAs will be upgraded and cycled through the Lab Spectrometer one-by-one; then cycled into the GBT Spectrometer until all eight LTAs and two spares have been upgraded and undergone extended qualification testing.
New Pulsar Backend...
The Cincinnati team has now begun to make significant progress on the actual application and have received notification that at least a portion of the requested Xilinx chips have been released and should be received soon. The UC Team will be conducting a "virtual demo" using a VNC setup between UC and GB room 137 this afternoon (02-MAR-07) and will be in Green Bank on 19-MAR-07 to conduct a face-to-face demo / project review.
Miscellaneous...
Nathan Sharp and Dave Woody report that their project to install new screen covers on the actuator controllers is now complete. Once Carla retruns, it would be advisable to conduct some on/off tests to determine the effectiveness of these new screens.
ALMA...
On-going efforts are continuing fairly smoothly on the ALMA front.
***Plans***
- Continue to investigate failed temp sensor...
- Complete documentation on LTA Upgrade Project...
- Get spare LTA and test fixture ready for upgrade testing efforts...
- Continue ALMA efforts as required...
Randy
We are in week two of the second development cycle of 2007 which can be viewed at PlanOfRecordC22007. Our next release is scheduled on 28 March 2007.
MarkClark, RamonCreager, and MikeMcCarty returned from PyCon 2007 in Addison, Texas this week.
Operational and user support was relatively light this week and included:
Modification Requests:
- MRs ready for integration/regression testing:
- MRs ready for sponsor testing:
- Develop New Pointing Pre-Processing Application (ModificationRequest5C706)
- Undergoing sponsor testing. RonGrider is writing a PTCS Project Note summarizing findings related to Focus scan processing that are now embodied in current version of Prepoint application. He is also revising mean error calculations in fitting methods.
- Extract Sampler Information from Log Files & Create Antenna Characterization Database (ModificationRequest3C107)
- Undergoing sponsor testing. A couple of extra requirements have been requested, 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)
- This is our #1 PTCS priority. JoeBrandt is investigating the device's timing and ways to make the system more reliable. Joe has written an inclinometer simulator to try to model and test the device's (undesired) behaviors.
- Create Pyrgeometer Manager (ModificationRequest2C22007?)
- We have started looking at this, but the inclinometer work is the #1 PTCS priority.
- Other Activities:
- Dynamic Scheduling - We are in the process of responding to comments received on the Overview.
- Complete Pointing Processing Description Memo - No progress
- Complete Documentation of Cross-Polarization Changes - In progress
- Evaluate GBT Data Handling Status & Future Options - In progress
- Replacement SDLT tape drive is in place.
- SDLT6000 on order.
- Current archive run near completion. Data earlier than Feb 1 2007 can now be found in
/home/archive
-
/home/archive Had a raid issue on Wednesday but is now rebuilt.
- Receiver room laptop upgraded from PIII to PIV and from Windows to Linux. Much faster.
PTCS -- PTCS Team
- Engineering work this week was limited to collecting data to try to derive a viscous friction term for the friction compensation scheme, and to map out the torque required to move the antenna at a constant rate as a function of azimuth.
- Pointing
- Kim is working on improvements to the low-level software that talks to the inclinometers. He believes the original code he wrote is less than optimal w.r.t. the sampling and time tagging. An improved version can be plugged into the existing manager.
- Last weekend's pointing run: attempted to search for timing as a cause of the pointing hysteresis problem. Normal X-band scan rate is 50'/min and 10Hz sampling. Initially tried 50Hz sampling at 200'/min but the fits always failed on the last elevation scan. Lowering to 25 Hz at 120'/minute worked consistently. Preliminary results show that the average forward/backward differences are similar (-0.73" vs -0.95") in azimuth. However, the two datapoints that could be fit at 200'/min show +3 and +5.4". Probably need to investigate why the fits are failing at the high rate when Frank returns
- Surface
- Todd extracted the Q-band moon scans from March 2005 and sent them to Fred for fitting with his dish surface model. He is now trying to fit the data with different mixes of actuator error and panel offset error. Bojan had attempted to fit to the data (in PTCS Project note 51) using only panel offset error, which did not fit very well in the farthest regions of the beam pattern.
- Other
- Brian continues to work on map reduction software. He delivered the cut at an X-band DCR map of 3c273.
- PTCS meeting will be held on Tuesday afternoon. Agenda will be sent out later today.
MIT/LL 43m Project -- Glen
- Normal Spacecraft tracking this week.
- GB Ops continues to do a very good job of handling the 43m monitoring and Disk Pack shipping.
- MIT/LL group arrives next week on Wednesday March 7.
- On Thursday they plan to measurement and swap out the Kildal feed with a higher frequency feed.
- On Friday they plan some calibration measurements.
- On Saturday they plan astronomical test observations.
Minor updates: We're preparing for final go at a Ka-band detection of a redshifted CO line. A few light bulbs went off late last week with regards to what we'd recommend as the best observing mode. Our conclusions from looking at the various data sets we have taken in various modes is that you need to, in order of priority, : 1) fire both diodes, 2) use subreflector nodding on a time scale < 2 min but that has yet to be well determined, and 3) use hybrid switching, and . (1) gets you the biggest advantage, (2) and (3) become more important as the weather deteriorates. We'll be putting together a recommendation on making subreflector nodding a standard observing mode.
Revision r1.12 - 02 Mar 2007 - 21:34 GMT - BobAnderson
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