Search observation

To make observations in drift scan mode:

AZ/ZA Pointing control widget

The telescope will now drive to the coordinates you specified. In the "Aostatus" display, the "requested" coordinates are not those you asked. Therefore, when the telescope gets to those coordinates, the "Aostatus" display will keep saying "Not tracking". Ignore that, just pay attention to the present AZ and ZA. When they attain the values you requested, you are ready to start.



Timing observation
> /home/pulsar/bin/polyco 1738+0333 -mjd 53100

For this to work, you have to have the pulsar ephemeris in the $TEMPO/tzpar directory (you can find the TEMPO directory by typing "echo $TEMPO", at AO this is /home/pulsar/tempo11/. If the variable is undefined in your login screen, type setenv TEMPO /home/pulsar/tempo11/)
> mv polyco .dat /share/obs4/usr/pulsar/p1684/
Image of single WAPP control widget

IMPORTANT!!!!! The source name in your polyco file has to be exactly the same as the name of the source you are pointing at. So if your target's name is the globular cluster NGC6760, and you are timing the known pulsar there (PSR J1911+0101), with that name in the polyco header, the polyco will not work! To check your pointing target's name, check the "aostatus" display. This name has to be the same as the name on top of the polyco file. So be careful about B/J names and globular cluster or supernova remnant names.


How to observe in schedule mode

You might want to observe a set of sources in quick succession; and sometimes you might want different integration times, sampling times, number of lags for each source. To avoid having to do this yourself, you can prepare a list of sources in advance with observing parameters for each source. This file should end in .cmd, and live in /share/obs4/usr/pulsar/p????/.

Here is how the entries would look like:

J0000+0000 600 usecs3=128 lags3=128 lagformat=16
J1111+1111 300 cal_toward usecs2=256 lags2=1024 lagformat=32
J2222+2222 1800
...

... where
  1. The first column is the source name
  2. The second column is the integration time
  3. The remaining columns are commands:
"usecs3=128" sets the sampling time of WAPP3 at 128 microsseconds
"lags2=1024" sets the number of lags of wapp2 to 1024
"lagformat" sets the number of bits in each sample. Generally for large sampling times ( > 256 us) this should be 32 bits, otherwise you might have bit overflow.
"cal_toward" activates the 25-Hz noise diode on the way to the pulsar - so no telescope time is wasted with calibration.
Details of other commands in WAPP's page and here.


Now, to make the observation, do the normal system setup.


Image of more widget


image of catalog gui

J0006+1834 00:06:04.8 +18:34:59 J 0 topo
J0030+0451  00:30:27.43 +04:51:39.75 J 0 topo
B0045+33 00:48:34.00 +34:12:08 J 0 topo
J0051+0423 00:51:30.1 +04:22:49 J 0 topo
J0137+16  01:37:23.87  16:54:42.23 J 0 topo
J0152+09  015219 094859.1 J 0 topo

First line: source name, second line: Right Ascension, third line: Declination, fourth line: coordinate system. Fifth line: associated velocity. Sixth line: reference frame for that velocity. Zero km/s in the topocentric reference frame forces the system to use precisely the sky frequency you specified.

Image of AO Observer Display widget

... and press the "End at Next Loop" button, on the bottom. This will end the present observation and stop the loop, incrementing the line number at the end. If you want to keep observing, just go back to the "Pulsar Catalog Observing" widget and press the "Start WAPP Pulsar Catalog Observation" button again.


Parameters that can appear in the schedule mode:




End the session

Last updated: June 4 2004
Paulo Freire