Haystack Observatory Postprocessing System (HOPS)
The Haystack Observatory Postprocessing System is a software package designed
to manipulate data generated by a MkIII, MkIV, or DiFX VLBI correlator. It is written
in C for Unix computers, and emphasises quality-control aspects of data
processing. It sits between the correlator and an image-processing package,
and performs basic fringe-fitting, data editing, problem diagnosis, and
correlator support functions. Below are links to some documents which
contain details of the various HOPS programs.
- Download
| Link: | HOPS Tarball The most recent tarball and an associated README file can be found here. The installation script uses autotools to properly configure for your architecture. You will need to have the pgplot package installed prior to building HOPS, otherwise it is self-contained. |
- General Information
- Memoranda
| PDF: | Amplitude Scaling (2011.2.14) A comparison of the visibility amplitudes produced by the Mk4 hardware correlator with those of the DiFX software correlator. |
| PDF: | Multitone Phasecal Mode in Fourfit (2011.3.25) A description of a new phasecal mode in fourfit, which uses all of the available tones in the band. |
- Aedit, the main edit/display program of HOPS.
| Link: |
General Information |
|
Picture: |
Psplot Command Example This is an array of time versus baseline, and represents an entire experiment. Each colored rectangle is a baseline/scan. The entire view surface is active, and the user can select, delete, filter and display data at will using the mouse.
Plot Command Example The color coding indicates the quality of the points. All aedit plots are active, in the sense that data can be interactively selected and deleted using the
cursor, and an arbitrary level of detailed information can be retrieved about any selected point using the cursor. This plot shows multiband delay versus
time, six plots per page. There are many possible axes and modes of plotting. |
- Fourfit, the fringe fitting program.
Link:
| General Information
Control File Example |
| Picture: |
Fringe Plot Example The fringe plot from fourfit graphically displays correlation amplitude and phase as functions of delay, delay rate, and time. Also shown are spectra, and detailed fit and quality control information. This level of information is considered essential for effective
quality control at a digital correlator. These fringe plots are screen entities, but can also be printed out on a single sheet of paper, or saved to a file. |
-
Vhelp output
| Link: |
Sample Vhelp Output This shows the output of a HOPS utility called vhelp, an online help system for the package. This sample provides a snapshot of the capabilities of the package as of
February 1995. These capabilities are undergoing fairly rapid enhancement. |
- Future Plans for the HOPS system
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781.981.5400 
