|Links||UNC Skynet||20m skynet interface||Log of 20m results.||Latest observation||NRAO Skynet main|
Details for various kinds of observing projects
|Main Advice||Mapping/Imaging Advice||Spectrum Observing Advice||Pulsar observing|
(Here is a list of many known pulsars)
After the observation, the system will attempt to run Scott's "prepfold" on the data, if it can find a "par" file, or if it can find the period and DM in a pulsar catalog. The resulting plots from prepfold will be put on the web in the "Skynet quick look" web area: http://www.gb.nrao.edu/20m/peak/latest/
If it cannot find information about the pulsar it will just list the name of the "psrfits" file, which you can copy and process offline.
Pulsar: B0329+54 psrfits file available on pork:/raid/scratch/cyborg/SkynetData/Skynet_58653_B0329+54_39900/Cyborg/ Skynet_58653_B0329+54_39900_47831_0001.fitsThe path designation following "pork:" is the path where the FITS file is located.
source /home/pulsar64/pulsar.bash prepfold -help prepfold -n 128 -nsub 128 -timing parfile fitsfilename parfile is /users/sransom/parfiles/psrname.par or /users/pdemores/tzpar/psrname.par If you know the period and DM: prepfold -n 128 -nsub 128 -nodmsearch <dmvalue> -p <period> fitsfilename (the period is in seconds)
So if you set the integration time to, say, 0.5 seconds, tsample is 4.19ms. In fact, if you set the integration
time to anything greater than 4.19ms, the sample time will be 4.19ms.
For shorter integration times, the system will set tsample to the closest power of two submultiple. For example if you set Tint = 0.001 second, what you get is 1.05 ms (i.e., 4.19/4). The smallest tsample that works reasonably well is 0.1ms; if shorter than that the data acquisition cannot keep up with the spectrometer, and most of the data gets lost. So as a practical matter, do not use Tint less than 0.0001 second. (actually 0.131 ms) The system is rigged to prevent Tint shorter than that.
Assuming we should have at least 50 time samples per pulsar period, then we can set a limit on the shortest pulsar period that it would be useful to observe. P ~ 50*(0.0001) = 0.005 seconds, hence observe pulsars with longer periods than 5 ms.