test collection

1. Introduction
2. Offered VLA Capabilities during the Next Semester
3. Performance of the VLA during the Next Semester
4. WIDAR Correlator
5. Documentation
6. Contact Information
7. Editor's Notes

The NSF National Radio Astronomy Observatory, NSF Green Bank Observatory, Central Development Laboratory, and Associated Universities, Inc. will be playing a major part in the January 2026 247th meeting of the American Astronomical Society.  Join the NSF NRAO leadership, staff, users, and students for a week sharing outstanding science results, press conferences, and technology developments.

Visit the NRAO in the exhibit hall, starting with the opening reception on Sunday evening.  Learn about the ALMA Wideband Sensitivity Upgrade, the ngVLA prototype antenna, new opportunities with the Green Bank Telescope and dysh, and capabilities for observing with the VLA, VLBA, and VLA Sky Survey (VLASS) from New Mexico Operations.  The exhibit will feature instrumentation pieces from the Central Development Laboratory.  Join the NRAO leadership for the NRAO Town Hall evening reception on Tuesday, January 6th to learn about the latest research and development initiatives.

Stop by the NRAO exhibit on Monday/Wednesday (5:30pm), and Tuesday/Thursday (9:00am) to learn about the new GBT reduction package, dysh.

Pre-register for the Synthesis Imaging Workshop, May 2026.

Sign up for the 2026 Virtual GBT Observer Training Workshop.

Subscribe to the NRAO Science Newsletter.  Follow the NRAO (Facebook, Twitter(X), Instagram, LinkedIn, and BlueSky);  GBO (Facebook, Twitter(X), and Instagram);  and AUI (Facebook, LinkedIn, and Instagram) on the various social media outlets.

See the meeting website for conference details.  The block schedule is available on the AAS Website with any location changes.

Each link in the list below presents scalar-averaged cross correlation spectra using several baselines in the C-configuration for each respective receiver band obtained in 2025's C-configuration. The channel separation is 125 kHz. The antennas are pointed to the north celestial pole and away from known RFI sources. Hanning smoothing has been applied to minimize Gibbs ringing. The scale is logarithmic, in dB, with arbitrary offset. The scale can be roughly calibrated by noting that the mean power level is roughly equal to the antenna SEFD in Jy. There is no bandpass calibration, so the downturns at the edges are due to the analog and/or digital filters.

In addition, each link contains .CSV files. These files contain the values needed to plot Amplitude vs Frequency for the RR and LL correlations. Similar to the above, the values are scalar-averaged cross correlations, Hanning smoothing has been applied, and no bandpass calibration has been performed. The amplitudes are in Janskys calibrated using the system temperature of the antennas. Due to the gain compression effect the reported values are better thought of as lower limits than absolute fluxes of the RFI.

• P-Band (224-480 MHz)
• L-Band (1-2 GHz)
• S-Band (2-4 GHz)
• C-Band (4-8 GHz)
• X-Band (8-12 GHz)
• Ku-Band (12-18 GHz)
• K-Band (18-26.5 GHz)
• Ka-Band (26.5-40 GHz)
• Q-Band (40-50 GHz)

A listing of the various RFI in this frequency band is available here.

Also available are spectra per 16 MHz subband.

CSV files for RR and LL - 05/27

CSV files for RR and LL - 05/29

CSV files for RR and LL - 06/09

CSV files for RR and LL - 06/09

CSV files for RR and LL - 06/26

CSV files for RR and LL - 06/26

CSV files for RR and LL - 07/24

CSV files for RR and LL - 07/24

CSV files for RR and LL - 08/04

CSV files for RR and LL - 08/04

 

Date: Tuesday March 25, 2025
Time: 9:30am to 4:45pm
Location: Bloomberg Center, Department of Physics and Astronomy, Room 462, Zoom (link to be provided at a later date to registered participants)

The National Radio Astronomy Observatory (NRAO) and ALMA Ambassadors cordially invite you to an ALMA Proposal Workshop at Johns Hopkins. This event is designed for all astronomers, with a particular goal to reach those that do not yet regularly utilize radio/millimeter data in their research. This one-day workshop will provide a primer on millimeter/radio interferometry and the basics of ALMA, a review of how to design and prepare successful ALMA proposals, and an overview of how best to take advantage of the latest resources developed by NRAO/ALMA (such as pipeline processing and simulating interferometric observations). An interactive session in the afternoon will offer a tutorial for preparing and submitting proposals with the ALMA Observing Tool, where attendees can start to build a foundation for their own Cycle 12 proposals (deadline April 24). Throughout the day, we will feature some of the latest science results from ALMA, including work from members of the JHU community, and offer a preview of the exciting new capabilities of ALMA coming in the next few years.

A free catered lunch will be provided on-site for registered participants. While attendance for the full day is not required, we hope you will join us for as much of the day as you can. Registration is completely free, but please complete the registration form by March 18 (sooner is better!) so that we can plan for lunch and ensure that the workshop is best tailored to your interests. Please note that in-person participation is limited to 30 people.

I look forward to welcoming you at Johns Hopkins University!

- Pallavi Patil (ALMA Ambassador)

09:15 – 09:30   Welcome and Coffee

09:30 – 09:35   Overview of the Workshop

09:35 – 10:00   ALMA Basics

10:00 – 10:45   Introduction to Interferometry and New Cycle 12 Capabilities 

10:45 – 11:00   Coffee Break

11:00 – 11:30   ALMA Proposal Preparation Process

11:30 – 12:15   Science Talks by Justin Otter and Jay Chittidi

12:15 – 13:30   Lunch

13:30 – 14:00   Wideband Sensitivity Upgrade + ALMA Archival Data Products

14:00 – 14:40   OT Demo

14:40 – 15:00   Break

15:00 – 16:30   OT Demo Continued, Practice, and Co-work

16:30 – 16:45   Wrap up and Final Questions

Before the event, please download and install the Cycle 12 ALMA Observing Tool (OT). Note that the Cycle 12 OT will not be available until the Call for Proposals is released on March 20:  https://almascience.nrao.edu/proposing/observing-tool

Room 138 of the Louis Stokes Health Sciences Library at Howard University:

Directions from Hotel to the venue:

Traveling to and from Charlottesville

Marriott Renaissance Hotel

We have made reservations for you and you will be getting confirmation numbers for your reservations soon.

The National Radio Astronomy Observatory (NRAO) invites scientists to participate in the Semester 2026B Call for Proposals for the Karl G. Jansky Very Large Array (VLA), the Robert C. Byrd Green Bank Telescope (GBT), and the Very Long Baseline Array (VLBA), High Sensitivity Array (HSA), and Global mm VLBI Array (GMVA).

The submission deadline for Semester 2026B proposals is Wednesday, 4 February 2026, at 17:00 EST (22:00 UTC).

Starting in 26B Large proposals can be submitted to the GBT every semester (see What's New in 26B).

For the VLA, the C-configuration will be available. It is anticipated there will be around 1200 hours on the VLA, 2600 hours on the GBT, and 755 hours on the VLBA available for science observing. Opportunities for Joint proposals will be available for ALMA, JWST, HST, Swift, Chandra, XMM-Newton, and IXPE. Joint Proposals with ALMA or JWST need to be submitted to the facility requesting the larger amount of observing time.

The array configurations available for joint ALMA/VLA will be: ALMA C-1 to C-8 and VLA C-configuration.

The NRAO 2026B Call for Proposals is for observations with the VLA, GBT, and VLBA/HSA/GMVA.  

A detailed timeline for the 26B Proposal Call is available here and summarized in the table below:

NRAO and GBO Users' Policy.  The NRAO and GBO Users' Policies have been updated and include the following:

• Updates to Proposal Requirements (Section 3.3.1):
  • The Scientific Justification must not include embedded or clickable hyperlinks within the text. Plain text URLs are permitted.
  • References must be included within the page limit of the Scientific Justification. While no specific citation format is required, reference entries must contain sufficient information to identify the work, consistent with standard professional practices.

GBT Large Proposals.  Starting in 26B, GBT Large proposals will be offered every semester.  However, for 26B, no large proposals with observations above 60 GHz will be considered.

GBT Cyclic Spectroscopy Backend.  The GBT cyclic spectroscopy backend will be included in the 26B call for proposals.

GBT Ultra-wideband Receiver (UWBR).  The GBT ultra-wideband receiver will be included in the 26B call for proposals.

Reminders:

• Constraints on Opportunities (Section 3.2.4): Starting with the 26A semester there will be the following constraints for VLA proposals with a PI from a non-US institution.
  
  1. Only scheduling priorities A and B will be allocated time; no filler time.
  2. The priority A and B time will be further restricted by applying a country cap of 10% and a total foreign cap of 30%
• Proprietary Period (Section 5.5.4): Beginning with the 26A semester the proprietary period will be increased from one to two years for all PIs.
• Use of AI (Section 3.3.2): Starting in 26A, proposers that use AI tools during proposal preparation should select the checkbox under the "AI Usage" section on the proposal's "General" page in the Proposal Submission Tool.
• Joint Proposals (Section 3.2.3):  To submit a joint proposal requires that both facilities are necessary to do the science.  See the memorandum of understandings (MOUs) on the Joint Proposal Opportunities page.  Joint Proposals with ALMA or JWST need to be submitted to the facility requesting the larger amount of observing time.
• Dissertation Plans.  The Dissertation Plan requirements (Section 7.2) were revised to specify that the plan must be written by the student.  Students that have dissertation plans as part of their NRAO profile will be REQUIRED to update their plans following a strict thesis template.  The LaTex and  Word formats are available online.
• PST Proposal Template.  The NRAO offers an optional Latex template for proposals.  Proposers are strongly encouraged to use this template for all proposal types - Regular, Large and DDTs and to follow the appropriate guidelines for font size, page margins and references.

See the NRAO and GBO Users' Policy page for more details.

NRAO Telescope Time Allocation Process

Proposals to the National Radio Astronomy Observatory (NRAO) for the scientific use of its telescopes are evaluated on the basis of scientific merit and technical feasibility using a panel-based proposal review system.  

Joint Observing Program

Observations that require combinations of the GBT, VLBA, and/or the VLA should submit a proposal for each of the requested telescopes.  The same Scientific Justification should be submitted with each proposal, and it should contain a clear justification for each telescope requested.  VLBI proposals which request the GBT or VLA as elements of the VLBI array do not need separate proposals.  For more details see the Joint Proposal page.

Access to joint observations with external facilities will continue for the VLA, VLBA and GBT for semester 26B. This includes joint observations with ALMA, the James Webb Space Telescope (JWST), the Hubble Space Telescope (HST), the Swift Gamma-Ray Burst MIssion, the Chandra X-ray Observatory, the XMM-Newton Project, the Imaging X-ray Polarimetry Explorer (IXPE), and the Fermi Gamma-ray Space Telescope. For more details see the Joint Proposal page.

Director's Discretionary Time Including Education and Public Outreach

Proposals for Director's Discretionary Time (DDT) may be submitted at any time. They must be submitted through the PST. DDT proposals are intended to address targets of opportunity, high-risk/high-return exploratory time, or other science opportunities deemed sufficiently urgent to justify prompt action. 

DDT proposals may also be submitted for the purpose of education and public outreach---for example, to image an iconic source or to support an educational opportunity for students. Such proposals should clearly justify the requirements for the requested time allocation and observing mode on any given instrument, and should describe the anticipated impact of the observation.  

While there is not an a priori limit to time that can be requested via DDT, it is expected that no more than 5% of the available science time on each telescope will be allocated for this purpose.

Technical Proposals

Proposals that are primarily focused on technical issues are allowed.  But the authors must include in the Scientific Justification how the results from the proposed observations will enable Science in the future.  For example, a proposal to develop a new strategy to improve phase calibration at high frequencies is acceptable, whereas a proposal to find good high frequency calibrators is the responsibility of the observatory (e.g., test time).

Other Proposal Opportunities

The NRAO would like to make users aware that there are additional proposal opportunities as follows:

• High Risk Proposals: As a means of maximizing its scientific impact through cutting-edge observations, the Observatory encourages the submission of high-risk/high-reward proposals.
• Commensal Observing: Commensal observations can be an effective way to maximize observing hours on NRAO telescopes, by allowing multiple experiments or systems to run simultaneously, when resources allow.  The Observatory may support two kinds of commensal observing:  commensal observing projects, and commensal systems.  For more information see the Commensal Observing with NRAO Telescopes page.
• Filler Programs: Some programs are not time critical, not strongly dependent on array configuration, or do not require highly subscribed LST ranges. Such programs may be able to take advantage of "filler" time.   The proposal should make clear in the abstract and early in the science justification that "filler" time is being requested.  If “filler” time is requested, the proposal will be ineligible for scheduling priority A or B.
  
• ANY Configuration Proposals: We encourage VLA proposals that can utilize time in the move configurations to be submitted as using 'ANY' configuration.  During the antenna move periods, the observing pressure can be much lower compared to in the standard configurations, providing increased probability for flexible configuration scheduling blocks to be observed.

Further information about each of these programs can be found on the Proposal Opportunities page.