RDV93 (Astrometric/Geodetic VLBA-93)
2012 JUN 27 18:00 DOY 179
Notes prepared by
David Gordon, Ed Himwich and John Gipson
NVI/GSFC
Special notes for this experiment
=================================
This session will use 2-bit sampling again, as in the last few RDV's.
Frequencies and channel bandwidths (8 MHz) are the same as in previous
RDV's. The bit rate will be 256 Mbits/sec. The 8 MHz, 2-bit sampling is
preferable to 16 MHz, 1-bit sampling because the 16 MHz filters are not
very good at the non-VLBA stations. The data will be correlated at the
VLBA using the DiFX software correlator.
There are 5 non-VLBA stations scheduled (FORTLEZA, MATERA, NYALES20,
TSUKUB32, and WETTZELL). These stations should see the "Special operations
notes for non-VLBA stations" section below for special instructions.
To facilitate fringe-finding, there are several long scans on fairly strong
sources at the beginning of the schedule and near the end. All stations please
try to be onsource and recording data for the first of these scans. There are
also several full-network scans in the middle of the session. These scans are:
Source Start DURATIONS
name yyddd-hhmmss Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz
0602+673 12179-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300|
0642+449 12179-180607| 300 300 300 300 300 300 300 300 300 300 300 300 300 300|
1030+415 12179-231420| 45 45 98 45 45 45 98 49 45 73 45 45 45 45 59|
0016+731 12180-065517| 90 89 151 83 98 84 151 107 84 103 96 95 77 56 111|
3C418 12180-082159| 45 45 102 45 45 45 102 82 45 70 45 45 45 61 80|
0016+731 12180-103147| 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200|
0016+731 12180-105937| 83 84 151 65 84 82 151 81 82 103 87 83 73 56 113|
0642+449 12180-174514| 300 300 300 300 300 300 300 300 300 300 300 300 300|
0602+673 12180-175114| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300|
Additional Notes:
- Two-bit sampling is used.
- In this RDV, all stations will record on Mark5A/B, except Tsukuba.
Tsukuba will record on K5 and the data will be
later transferred to Mark5A at Haystack Observatory.
- The synch time for the VLBA DiFX correlator using Mark5 is only a
few seconds. Because of this, the 'early' start has been reduced to
10 seconds.
- The fluxes use our most recent models.
Purpose
=======
This is the third of six coordinated astrometric/geodetic sessions
in 2012 that use the full 10-station VLBA plus up to 10 geodetic
stations capable of recording VLBA modes. This year's series is a
continuation of the highly successful RDV series begun in 1997.
These experiments are being coordinated by the geodetic/astrometric
VLBI programs of USNO, NASA, and NRAO. The experiments have been
designed so that the same data set may be used by each agency for its
particular goals.
USNO and Bordeaux Observatory will perform imaging and correction for
source structure. These sources will establish a set of core reference
sources with known structure and precisely known positions. These data
will provide the basis for evaluating the long term stability of the
radio reference frame and the ultimate accuracy of wide angle
astrometric measurements of extragalactic radio sources using VLBI.
NASA will analyze this data to determine and maintain a high accuracy
terrestrial reference frame. The data will incorporate the VLBA stations
into the VLBI reference frame through the inclusion of other geodetic
stations for which we have long histories. The data will also produce
the most accurate Earth rotation results ever produced. We will use
these data to make accurate absolute measurements of UT1.
NRAO will use these sessions to provide a service to users who
require high quality positions for a small number of sources. While
the quality of these results will be high, the observing and data
reduction overhead required will be minimal because a small number of
such sources can be incorporated into a session of the regular geodetic
observations, instead of requiring special observations.
Sources for this series of experiments will be selected using the
proposed approach. For each experiment we will select a set of 70-80
sources from the pool of geodetic, astrometric, and monitoring sources.
About 40-50 of these will remain the same from experiment to experiment
and will be chosen to optimize the goals of the three groups. A small
number of poorly observed and/or new requested sources may also be
included to obtain or improve their positions.
Schedule information
====================
This is a new schedule generated by David Gordon at GSFC using sked.
Schedule file name: rdv93.skd
On ftp.aoc.nrao.edu (aspen):
VLBA Pointing files:
rdv93crd.br rdv93crd.fd rdv93crd.hn rdv93crd.kp rdv93crd.la
rdv93crd.mk rdv93crd.nl rdv93crd.ov rdv93crd.pt rdv93crd.sc
Summary file: rdv93.sksum
Sked file: rdv93.skd
Text file: rdv93.txt
Vex file: rdv93.vex
At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2012/rdv93)
Sked file: rdv93.skd
Text file: rdv93.txt
This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations
are: FORTLEZA, MATERA, NYALES20, TSUKUB32, and WETTZELL. Below is the sked
summary:
Key: Br=BR-VLBA Fd=FD-VLBA Ft=FORTLEZA Hn=HN-VLBA Kp=KP-VLBA
La=LA-VLBA Ma=MATERA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20
Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Ts=TSUKUB32 Wz=WETTZELL
Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz Avg
% obs. time: 51 51 42 46 51 50 43 50 49 41 52 51 45 29 34 46
% cal. time: 4 4 3 4 4 4 4 4 4 4 4 4 4 4 4 4
% slew time: 24 23 42 23 24 23 27 23 23 18 24 24 23 16 13 24
% idle time: 20 22 12 26 21 23 25 22 24 36 20 21 27 51 48 27
total # scans: 328 319 258 313 318 311 321 314 306 323 317 316 308 330 347 315
# scans/hour : 14 13 11 13 13 13 13 13 13 13 13 13 13 14 14 13
Avg scan (sec): 133 137 142 128 139 139 116 137 137 110 140 139 127 75 83 124
# data tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16
# Mk5 tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16
Total GBytes: 1688 1687 1410 1554 1703 1669 1452 1658 1622 1400 1716 1700 1524 1010 1168 1531
Total GB(M5): 1500 1499 1254 1381 1514 1484 1291 1474 1442 1244 1526 1511 1354 898 1038 1361
# OF OBSERVATIONS BY BASELINE
| Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz StnTotal
-------------------------------------------------------------------------------------
Br| 220 50 211 241 235 62 207 220 114 256 245 151 134 80 2426
Fd| 94 206 283 278 54 192 249 71 244 285 204 74 63 2517
Ft| 92 78 86 149 42 96 96 58 81 162 17 137 1238
Hn| 195 213 109 128 250 133 178 209 214 82 123 2343
Kp| 285 48 203 243 78 272 296 183 88 62 2555
La| 62 184 264 87 250 302 195 78 72 2591
Ma| 20 78 217 37 56 83 112 287 1374
Mk| 160 60 236 193 125 162 30 1942
Nl| 107 218 258 214 76 93 2526
Ny| 80 82 86 166 251 1628
Ov| 263 162 117 52 2423
Pt| 192 83 68 2613
Sc| 45 90 2106
Ts| 136 1370
Wz| 1544
Number of 2-station scans: 217
Number of 3-station scans: 139
Number of 4-station scans: 130
Number of 5-station scans: 42
Number of 6-station scans: 37
Number of 7-station scans: 57
Number of 8-station scans: 40
Number of 9-station scans: 50
Number of 10-station scans: 57
Number of 11-station scans: 58
Number of 12-station scans: 15
Number of 13-station scans: 16
Number of 14-station scans: 4
Number of 15-station scans: 7
Total # of scans, observations: 869 15598
INTENSIVE BREAKS
================
There is no INT01 UT1 session on June 27, so no intensive break is
included in the schedule. However, there may be a USNO/NRAO UT1
intensive session using PIETOWN and MK-VLBA. The timing for this is
somewhat flexible - sometime between 15:00 and 23:00 UTC. Therefore,
PT and MK may be taken out of RDV93 for an ~1.5-2.0 hr period sometime
during that window. We will leave the timing of this break to the
discretion of the VLBA operators. From our standpoint, there is no
particular period that is better or worse than another, and the loss of
these two antennas for a short period should have only a minimal effect.
SOURCE SELECTION
================
There are a total of 92 sources scheduled in this session. Among them,
30 sources are from the astrometric monitoring list, 35 are from the
geodetic monitoring list, and 27 are previously observed sources that
have only a few observations or were observed in only one session.
SCHEDULING ALGORITHMS
=====================
This schedule uses the "SRCEVN SQRT" mode of Sked. In the absence of any
constraints, Sked will preferentially observe strong sources that have
high visibility. This mode attempts to smooth out the number of
observations per source.
RECORDING MODE and FREQUENCIES
==============================
The data will be recorded using the following setup:
8 channels
1:2 fan-out
16 MHz sample rate
2-bit sampling
This recording mode is designated 256-8(RDV). There is no correlator
speed-up factor.
The frequency sequence covers 490 MHz at X-band and 140 MHz at S-band
using 4 channels in each band. This span fits in one VLBA receiver passband
but it uses both the high and low parts of the geodetic receivers. Because
only 8 channels total are available when observing with the VLBA stations,
a wider spanned bandwidth is not advisable.
The following tables list the setup for the VLBA stations, the geodetic
stations with K5 back ends, and the geodetic stations with Mark IV back
ends. These are the SAME frequencies used in all the standard RDV sessions.
VLBA | TSUKUB32
Chan Sky Tracks LO IF BBC | LO IF BBC #
1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7680 1 725.99 3
2 X 8475.99 10,12,14,16 7900 B 575.99| 7680 1 795.99 4
3 X 8790.99 18,20,22,24 7900 B 890.99| 8080 3 710.99 5
4 X 8895.99 26,28,30,32 7900 B 995.99| 8080 3 815.99 6
5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1600 2 632.99 9
6 S 2262.99 11,13,15,17 2900 A 637.01| 1600 2 662.99 10
7 S 2352.99 19,21,23,25 2900 A 547.01| 1600 2 752.99 13
8 S 2372.99 27,29,31,33 2900 A 527.01| 1600 2 772.99 14
FORTLEZA, NYALES20,
VLBA | MATERA, WETTZELL
Chan Sky Tracks LO IF BBC | LO IF VC VC# Patch
1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 8080.0 1 325.99 3 H
2 X 8475.99 10,12,14,16 7900 B 575.99| 8080.0 1 395.99 4 H
3 X 8790.99 18,20,22,24 7900 B 890.99| 8580.1 3 210.89 5 3(H)
4 X 8895.99 26,28,30,32 7900 B 995.99| 8580.1 3 315.89 6 3(H)
5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 2020.0 2 212.99 9 L
6 S 2262.99 11,13,15,17 2900 A 637.01| 2020.0 2 242.99 10 H
7 S 2352.99 19,21,23,25 2900 A 547.01| 2020.0 2 332.99 13 H
8 S 2372.99 27,29,31,33 2900 A 527.01| 2020.0 2 352.99 14 H
Special operations for non-VLBA stations:
=========================================
FORTLEZA, MATERA, NYALES20, and WETTZELL:
These stations have Mark IV or Mark 5 racks.
Please use the procedures generated by DRUDG. VCs 3 & 4 are used at
X-band with IF 1. VCs 5 & 6 are used at X-band with IF 3. VCs 9, 10,
13 & 14 are used at S-band with IF B.
The IF3 command in the procedure IFDSX assumes that VC3 and VC10
will be patched to High. Please verify that the switches for your
IF3 module are wired this way, and if they are not please edit the
IF3 command to change the switches. The standard wiring is described
in "help=if3". If you have questions about the wiring, please
contact Brian Corey at Haystack.
TSUKUB32:
This station uses K4-2 VCs and a K5 recorder.
Please transfer data to Haystack in Mark IV format.
Use the procedures generated by DRUDG. Be sure to set your rack type
to K4-2, not K4-2/M4, if that change has not already been
made. Please note you will need to comment out the incorrect VC
commands in the VCSX8 procedure after the comment about these
converters being present, but not used. This will be corrected in a
future DRUDG release. Please also set the attenuation and detector
appropriately in the va=.. and vb=... commands. The tpicd commands
in SX8M12A should be benign and do not need to be commented out
unless they cause a problem.
If you wish to record back-up channels, please add appropriate
valo=..., va=... vblo=... and vb=... commands in the VCSX8 procedure.
CHECKLIST for non-VLBA stations
===============================
Please follow the checklist below to ensure you have done all the
necessary steps for this experiment:
1. Make .prc file with DRUDG and check them out, or use the procedures
from the last session. Check out parity check procedures.
2. Make the .snp file with DRUDG.
3. Set up your system to monitor the clocks with the "gps-fmout" or
"fmout-gps" commands. If you have questions about this, please
contact Ed Himwich as soon as possible.
4. Send a "ready" message an hour or so before the experiment to the
ivs-ops mail list. Copy analysts@nrao.edu on your ready message.
5. Send a "start" message soon after you have started recording.
Copy analysts@nrao.edu on the message.
6. At the end of the experiment, send a "finish" message summarizing
how the experiment was conducted. Copy analysts@nrao.edu on
your message.
7. Transfer your log files to your normal log file data center.
The directories for three possible servers are listed below:
ftp cddisin.gsfc.nasa.gov/ivsincoming
directory on vlbeer: jun12
directory on aspen: /astronomy/jun12/rdv93
or /home/archive/e2e/archive/operations/VLBA/observe/jun12/rdv93
NOTE: If you don't normally use aspen, you should not put your log
file on that server. The VLBA correlator knows where to find your
log files.
Correlation
===========
This experiment will be correlated at the VLBA on the VLBA-DiFX
software correlator. Disks should be shipped (except Tsukuba) to
Socorro as soon after the experiment as is practical.
The Tsukuba data should be e-transfered to Haystack in Mark IV
format as soon after the experiment as is practical. Ny Alesund
may also use e-transfer and will need to coordinate this with
Haystack if so.
Socorro address for media shipping:
VLBA Array Operations Center
National Radio Astronomy Observatory
Attn: Juan Cordova
1003 Lopezville Road
Socorro, NM 87801
U.S.A.
Phone: 575-835-7000
Shipping and VLBA contact information is also given at:
https://science.nrao.edu/facilities/vlba/contact/shipping_information.
Please use one of the recommended shipping companies (FedEx, UPS,
DHL, TNT). The VLBA needs to process the session at their correlator
as soon as possible because of limited media. They prefer to have the
data within one week of the observation, but in no case later than two
weeks after the observation. Therefore, please ship your media
to the VLBA the same day the session ends or the next business day
(just like the R1/R4 media is shipped). If you know that there is
going to be a problem sending your media to the VLBA the same day
the session ends or the next business day, please let us
(ivscc@ivscc.gsfc.nasa.gov and David.Gordon-1@nasa.gov) know as
soon as possible so that we, along with the VLBA, can determine the
best course of action. If you have any questions or comments,
please let us know.