| vs07x Results
Submitted checklist.txt and checklist.tex is also available |
[Summary | AIPS | Difmap ] |
| Observation code | : | vs07x | AIPS Version | : | 15APR99 |
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| Date of Observation | : | 1999/38 | Difmap Version | : | 2.3c | |||
| Source Name | : | J0920+444 | vsop_difmap used | : | Yes | |||
| Calibration Source(s) | : | |||||||
| Ground telescopes | : | BR, FD, MK, SC | Model Fitted to data | : | Yes | |||
| Tracking Station(s) | : | TZ | Image made | : | Yes | |||
| Correlator | : | Socorro |
| Abstract
Doing least squares solutions, the AIPS task FRING was not useful for space baselines. The coarse search found appr. -80 ns delay values for HALCA, and the least squares method 'refined' it to several hundreds of ns's. Therefore coarse fringe-fitting solution (SN 4) was applied for HALCA, and the fine solution (SN 5) just for the ground telescopes. These two SN tables were merged into CL 5 table. Task KRING was used also, but did not lead to better solutions. The CLEAN map and the model-fit are not inconsistent with the pre-launch and other higher frequency ground-only images. The model with two elliptical Gaussians and a point source made a good fit. |
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| FITLD | digicorr 1 delcorr 1 |
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| MSORT |
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| INDXR | cparm = 0, 0, 0.5, 1, 1, 0 |
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No PI letter, input scan break taken from NRAO ftp site. |
| OBTAB | antenna 11 |
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OB table data into the AN table |
| ACCOR | solint 2 |
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| CLCAL | opcode 'cali' interpol '2pt' refant = 1 antennas 1, 2, 6, 10, 11 |
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| VLOG |
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| ANTAB |
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gain curve informatin from VSOP calibration web page. Nominal Tsys used for Hobart and HALCA. Slight difference between HALCA IF1 and IF2 (96 & 102 K) based on earlier experience. | |
| APCAL | antennas: 1, 2, 6, 10, 11 |
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Weather information was used. |
| CLCAL | opcode 'cali' interpol '2pt' refant = 1 antennas 1, 2, 6, 10, 11 |
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Amplitude calibration solutions applied, SN table from ACCOR was not used. |
| PCLOD |
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PC table made | |
| PCCOR | timer 0 8 0 0 0 8 2 0 cutoff 0 refant 1 |
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| CLCAL | opcode 'calp' interpol '2pt' refant 1 antennas 1, 2, 6, 10, 11 |
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| UVFLG |
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| FRING | docalib 1 antennas 1, 2, 6, 10, 11 dofit 1, 2, 6, 10, 11 flagver 1 gainuse 4 refant 1 search 2, 6, 10 solint 3 aparm 2, 0, 0, 0, 0, 1, 3, 0, 1, 0 dparm 3, 400, 100, 0, 1 |
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With dparm(5) = 0 the least squares solutions were wrong. FFT solutions worked, and kept for HALCA. Refined fringe solutions were made for ground telescopes only, with good convergence. (see next FRING) |
| FRING | docalib 1 antennas 1, 2, 6, 10 dofit 1, 2, 6, 10 flagver 1 gainuse 4 refant 1 search 2, 6, 10 solint 3 aparm 2, 0, 0, 0, 0, 1, 3, 0, 1, 0 dparm 3, 400, 100, 0 |
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for ground telescopes only |
| CLCAL | antenna 1, 11 opcode 'calp' interpol 'ambg' refant 1 |
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Coarse FFT solutions for HALCA was applied, fine least squares solutions in FRING did not converge, reason unknown. |
| CLCAL | antenna 1, 2, 6, 10 opcode 'calp' interpol 'ambg' refant 1 |
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Fine least squares solutions was applied for ground telescopes. |
| SPLIT | aparm = 3, 2.06, 0, 1, 0 |
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Create single-source file, IFs averaged, aparm(2) from DTSUM |
| FITTP |
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Data written out for analysis in Difmap. |
AIPS Input Files
| INDXR.TXT ANTAB.TXT |
Comments No PI letter, information from NRAO ftp site. Flags, Tsys data, etc., are from the v080ical.vlba and the vlba_gains.key files. |
AIPS Output Files
| Phase selfcal applied? | Yes |
| Global amplitude selfcal (gscal) applied? | Yes |
| Amplitude selfcal on non-global timescales used? | No |
| Modelfit made and saved? | Yes |
| Image Made and saved? | Yes |
| Comments on Difmap processing
Two elliptical Gaussians and a point source was used to model the brightness distribution. |
| Image | ||||
| Ampl, Phase vs (u,v) Distance PS (55 kb) JPEG (45 kb) |
Ampl, Phase vs Time PS (267 kb) JPEG 1, 2, 3 |
(u,v) Coverage PS (30 kb) JPEG (31 kb) | Closure Phase vs Time PS (292 kb) JPEG 1, 2 |
Clean Image PS (39 kb) JPEG (48 kb) |
| Modelfit | ||||
| Ampl, Phase vs (u,v) Distance PS (55 kb) JPEG (45 kb) |
Ampl, Phase vs Time PS (267 kb) JPEG 1, 2, 3 |
(u,v) Coverage PS (30 kb) JPEG (31 kb) | Closure Phase vs Time PS (292 kb) JPEG 1, 2 |
Image with model components PS (35 kb) JPEG (39 kb) |
More details on the Images and Modelfits are found in this page.
