Santa Barbara Instrument Group ST-i Operating Manual page 22

Frame Size – Planet mode allows you to select a portion of the CCD's
field of view (FOV) for faster rep rates due to smaller downloads.
It's great for focusing the telescope on a star. The other three Full
settings all show the full FOV of the CCD but are slower than
Planet mode because there's more data to download.
Full-High uses high-resolution mode to show you all 648 x 486
pixels. Full-Low uses low resolution (2x2 binning) which is faster
and more sensitive since there are fewer pixels to download and
the pixels are larger. Finally Full works in conjunction with
Planet mode and the Camera Setup such that when the camera is
set to Auto resolution mode Full uses the low-resolution mode for
faster downloads then switches to high-resolution for Planet mode.
Dark Frames – For most objects you won't need to take dark frames in
Focus mode to frame and focus the object because the exposures
tend to be short and the build up of dark current minimal. On
some dim objects though, checking this item, which uses dark
subtracted images for Focus mode, can help to pull the object out
of the noise. The update rate is slightly slower when using dark
frames so only use this when you need to.
Filter Warm Pix – Checking this box will cause the software to
automatically filter out warm (bright) pixels. This will produce a
smoother background. with less "salt-and-pepper" appearance.
Update Mode – Sometimes you want to tweak the focus, look at an image,
tweak it again, etc. Setting this to Manual causes the Focus mode
to pause between images until the Space Bar is hit or you click the
Pause/Resume button.
Exposure delay – This will put a delay of x seconds between exposures
Turbo Mode – This is used with slower cameras to stop the shutter from
moving in order to speed up focusing. It is not needed with the
ST-i camera.
Peak – This shows the position and brightness of the brightest pixel in the
Focus mode image. We'll use this later to get the best focus by
maximizing the Peak on a star.
Pause/Resume – Click this button at any time to pause or resume the focus
mode. This can be handy for going back and forth between the
telescope and the computer or for studying the images.
You can read more about the other items in the Help but we now know
enough for basic operation. Exit Focus Mode by closing the Focus Mode
dialog or closing the image window.
SBIG ST-i Manual
20