PlanetPol is a stellar polarimetre designed to measure fractional polarisations of 10^-6 or less. with this sensitivity should be capable of detecting the polarisation signature of so-called hot Jupiter.

PlanetPol is a visiting instrument and it is supported by their own staff. View of PlanetPol in the WHT Cassegrain Port.

• USER> STATION CASS
• USER> INSTRUMENT ISIS
• USER> AGSELECT CASSE
• Zeroset AZ and ALT

• USER> AZ 298
• USER> ALT 89
• USER> ENG
• USER> ZERO AZ TAR
• USER> ZERO ALT TAR

Drive AZ and ALT slowly in + direction over the zeroset target points, then switch to computer control again

• USER> ZERO AZ ABS
• USER> ZERO ALT ABS

• USER> ZERO ROT ABS
• USER> WAVELENGTH 0.6
• USER> TEMP ...
• USER> PRESS ...
• USER> HUMI ...
• USER> UT1UTC ...
• USER> CAL LAST
• USER> FOCUS 97.6 (03/05/2005)

Autoguider:
Use the standard uDAS autoguider for CASS with AUTOFOCUS 2900. From leo (whtdas3) with 'obssys 1', 'startobssys' and 'startag AG6' followed by 'option 4'. No window is required!
The monitor should then display a camera mimic showing temperatures (these are presently rather inaccurate) and camera status. DS9 display tool will also appear as well as the TV Guider Control. This box allows you to change exposure times, take fields and set the TV and Guider going. Images are piped directly to the display tool.

GSS is used for finding guide stars, connect to LPVS3 via LAT and login as GSS. Select WHT and instrument ISI.
With 'ICL>PRAG r t' command you move the guide probe to the required position.
PRAG sends the PROBE command to the TCS, this is essential for correct guiding.
In order not to interfere with the observer using LPVS1 it is recommended to send the PRAG command from the TO terminal. Connect to LPVF/G via LAT and login as OBSERVER, when asked if you want to run the observing system answer 'No', then type 'ICL'. On the ICL prompt you then type:
ICL> load [.vsd]to_prag.icl.
From now on you can move the probe from this terminal using the command 'to_prag r t'.

The orientation of the movements of PlanetPol respect the sky:

                                     TCS keyword 
    
                               

Check the pointing from previous run in CASS.

ICL:> AGMIRROR OUT.

Telescope focus: 97.6

Rotator centre:
After an instrument change you are supposed to determine the rotator centre and to run the 7 star calibrate procedure, this takes about 20 minutes.
Use TVSCALE 5 and direct viewing, this is the top surface of the comparison mirror (ICL> AGCOMP).
Measure the star position on the TV screen (x,y), then rotate 180 degrees and measure again. Calculate the midpoint, this is your rotator centre.

Calibrate procedure:
Calibrate is done on the rotator centre with the rotator tracking turned off (USER> ROT MOUNT xxx).

Determine aperture offset:
There is no need for defining an aperture.

Acquisition:

PlanetPol observe with a Rot Sky 0, so it is important to be sure that the rotator doesn`t reach the limit switch.
The adquisition camera for centering the object is in PlanetPol adquisition software.

For a good telescope pointing the objects is really close to science position.

Autoguiding:
GSS tells us where to move the probe to, in order to pick up light from suitable guidestars:

• $> GSS
• GSS> CONFIG WHT CASS
• GSS> ROT {sky pa}
• GSS> SEA hh mm ss dd mm ss equinox
• GSS> EXIT
• $> TYPE OUTPUT.GS

Choose a 13-15 mag star from the output list, and send the guideprobe to the required position by typing:
'to_prag r t' in the corresponding window.

Once the guideprobe is in position you take a 'field' using the TV Guider Control (if not in TV mode already). Then start guiding. Check the status on the TCS DISPLAY changes from TRACKING to A/GUIDE.

• The data are recorder in PlanetPol system.

PlanetPol is placed in the CASS port, and we have to be sure that the anything can block the optical path.

ICL:> agmirror out

-------- © 2005 Isaac Newton Group of Telescopes --------
Last Updated: 03 May 2005 Juan Carlos Guerra jcg@ing.iac.es