Focus
To determine the best telescope focus the observer should select a suitable
stellar field (e.g. landolt standard - see red folder in control room, or
http://www.ing.iac.es/ds/landscape).
SYS>quickfocusrun
A window will pop up: enter the number of exposures, exposure time,
start
focus position (mm), focus increment steps (mm), and number of arcseconds
to offset the telescope between each exposure.
Hit RUN in the quickfocus window.
This will begin taking an exposure for each focus step while offseting the
telscope by the number of arcseconds chosen. When finished, quickfocus will
write the focus image to the next run number (eg r999999.fit).
To analyze focus image go to iraf. You may use the task jkt_qstarfocus,
located in the ing package.
To run jkt_qstarfocus type the following in iraf:
ing>jkt_qstarfocus 'filename'
Select the desired stars to anaylze by choosing the first exposure of each
star (the one with the greatest offset)
with the 'm' key. Press 'q' when finished. See what the jkt_qstarfocus
chose as the best focus.
Now set the telescope to the new focus value! (It is a good idea to glance
the field and check out the new focus using imexam) Remember to note the
focus value in the Observing Log Book by the TCS.
SYS>focus 39.70
Observing
Finally ready to start on your targets/standards. Find a target that has
the lowest airmass (compare LST to RA of target, diff as little as
possible).
*USER>gocat yourtarget
change to the filter you want
SYS>filter n
Exposing: For exposures longer than about 120 seconds you need a