Next: 3 Preparation for Observing
Previous: 2.2 Filters
2.3 Focusing
For now, we are focusing the old fashioned way. GoTo a fairly bright standard star (not an index star, but
something fainter, ~8-10 Mag.) and move the Mirror Slide IN
Turn on the intensifier gain, and turn it up until you get a good image of the star in the video screen.
Using the soft Hand Paddle, focus the image of the star. A good way to focus is to move the focus OUT or "-" to a
given size donut and note the focus value. Then go back through the best focus and "IN" or "+" to a donut about the
same size and move the focus to that position.
See if the calculated position matches what your eye tells you is a good focus. You can also use the Focus Tool button
on the dark blue tool bar to do this.
In the near future we will have a more quantitative focus routine which would allow you to look at the FWHM in IRAF
of a set of star images taken at various foci.
We will also soon have an auto-focusing routine in V and CIA which will go through the focus process on it's own
and suggest a focus value. It will calculate FWHM and ellipticity of a star image and then send a move focus command to
ACE, then repeat as needed until a good focus is achieved.
Indexing and focusing procedures take only a few minutes once you are familiar with them.
Next: 3 Preparation for Observing
Previous: 2.2 Filters
Updated: 2/10/99