News for VLBA/HSA/VLBI Proposers and Observers

July 8, 2013

2014A Call for Proposals Announced

The 2014A Call for Proposals was announced on January 3, 2013.  Proposal deadline is August 1, 2013 at 17:00 Eastern Daylight Time (21:00 UTC).

January 3, 2013

2013B Call for Proposals Announced

The 2013B Call for Proposals was announced on January 3, 2013.  Proposal deadline is February 1, 2013 at 17:00 Eastern Standard Time (22:00 UTC)..

December 31, 2011

VLBA flag problems (Nov 10 to Dec 22)

During the second week of November, upgrades were made at Pie Town in support of the upgraded C-band receiver. These changes have transferred monitor and control of some antenna electronics from the "legacy" station computer to the modern system which is based on EVLA software. This new system is working well, however the legacy system, which is still responsible for generating flags for the station, was perpetually flagging data based on monitor points that no longer exist. The Hancock antenna C-band system was upgraded in December with the same issue beginning with observations made on Dec 10.

Data observed after Nov 10 and correlated before Dec 7 will have a single erroneous flag for Pie Town encompassing the entire observation. Data observed between Dec 7 and Dec 22 won't have any flags for Pie Town or Hancock. Data observed after Dec 22 should be back to normal.

VLBA operations staff have regenerated flag data for the Nov 10 through Dec 22 period. Users wishing to restore proper flags can follow the instructions to download cal.vlba.gz and then follow instructions in the AIPS Cookbook. The section titled Automatic formatting of VLBA and VLBA-like log files will explain how to use VLOG and UVFLG to load flags from the downloaded file. You may want to make a backup (with TASAV) of the original FL table before deleting it (with EXTD) just in case you want to go back to the original flags.

Questions regarding the flagging problem and its corrections should be directed at the NRAO helpdesk.

August 29, 2011

Hancock VLBA station temporarily shut down by hurricane Irene

The Hancock VLBA station was put into shutdown mode in the morning of August 27 in anticipation of high winds, heavy rains and power loss due to hurricane Irene.  Commercial power was lost at approximately 3 am Sunday morning and has not yet been restored.  The site techs were able to reach the station on Monday, August 29 and determined that there is no obvious damage to the antenna or structures.  Numerous trees are down around the site and on the roads and power lines have been downed by fallen trees.  It may take several days before power is restored, however, backup generators for critical systems (maser, cryogenics, etc.) are working so we anticipate a smooth return to operations once power is restored.

August 8, 2011

Error found in EOP corrections in AIPS

Versions of the AIPS task CLCOR released between Sept. 21, 2009 and Aug. 4, 2011 used the wrong sign on the station Y coordinate when calculating Earth Orientation Parameter (EOP) corrections. The main adverse impact will be on phase referencing projects for which sufficiently large EOP corrections were made that the difference in the relative correction between calibrator and target is significant.  For more details click here.

July 6, 2011

Los Alamos antenna back in operation

In the evening of July 6, 2011 the danger posed by the Las Conchas fire had subsided sufficiently that the Los Alamos VLBA antenna was put back in operation.  It has been taking part in VLBA observations since.

July 2, 2011

Las Conchas Fire near Los Alamos

The Las Conchas Fire that started on June 26, 2011, came within a few miles of the LA VLBA antenna. The LA station is out of danger, but the fire continues to burn and is not yet contained. The Los Alamos National Laboratory remains closed. NRAO therefore has no access to the antenna at this time, and LA cannot currently be included in VLBA observations.

June 30, 2011

Call for proposals for semester 2012A

The June 30, 2011 NRAO eNews contains the Call for Proposals for the GBT, EVLA, and VLBA/HSA/VLBI, along with general news for proposers.

January 7, 2011

Call for proposals for semester 2011B

The January 7, 2011 NRAO eNews contains the Call for Proposals for the GBT, EVLA, and VLBA/HSA/VLBI, along with general news for proposers.

September 15, 2010

Call for proposals for trimester 2011A

The September 15, 2010 NRAO eNews contains the Call for Proposals for the GBT, EVLA, and VLBA/HSA/VLBI, along with general news for proposers.

June 21, 2010

VLBA Pie Town azimuth track fixed

The Pie Town VLBA antenna was restored to full service on June 17, 2010, after antenna mechanics were able to effect a repair to the split in the rail. The damaged rail section was regrouted and the split rail was welded. It is believed that the split in the rail was caused by a poor quality weld of the rail to the mounting plate during the construction of PT. It appears that this weld cracked during cooling and then slowly propagated up the rail until the failure occurred.

June 1, 2010

VLBA Pie Town antenna down for repair of azimuth track

During a routine inspection of the Pie Town VLBA azimuth track on May 25, 2010, a split in the rail and grouting near bolt 20 was discovered. Until a repair is completed, the PT antenna will be unavailable for observing. Several options for the repair are under consideration, but PT will be out of service until at least July 1, 2010.

May 14, 2010

Call for proposals for trimester 2010C

The May 14, 2010 NRAO eNews contains the Call for Proposals for the GBT, EVLA, and VLBA/HSA/VLBI, along with general news for proposers.

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