You can also use the Postprocess Imexam
to measure the FWHM of the
images (use a-key), quite imexam by typing q-key
Take another focus sequence with finer focus step size
if needed.
If you have problems with the BIAS/imexam
you can use iraf/imexam at florence.
- in florence xterm window type xgterm &
- in xgterm window type ecl and ds9 &
- display saved stancam image displ /data/stancam/STnnmmxxxxx[1] 1 fi+
where nnmmxxxxx stands for the prefix and the number of the image
(see the testimage " /data/stancam/EXfocus.fits")
- type imexam and move the cursor on top of the star and press
r for radial profile and/or a or , for aperture photometry
- quit imexam by pressing q
Note, that the telescope focus vs FWHM curve is
rather broad around the optimum focus.
