The IFU FoV is overlayed on the image.
And the sky slit location is also shown about 5.2 arcmin north from the IFU FoV.
Plsease note the relative position of the sky slit with respect to the IFU FoV is uncertain (~10 arcsec).
When the FoV marker is selected, 5 green dots appeare.
Grabing the central point, you can move the FoV marker.
Grabing the corners of the FoV marker, you can rotate the marker.
"Roll" value shows the position angle (Instor_PA in an OPE file) of the FOCAS IFU FoV.
You can also change the positon angle by changing the value.
The Insrot_PA should be specified in an OPE file.