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SBIG CFW-9
Page 9
There are individual commands in the Filter menu with hot keys
for positioning the filter wheel. Also the Camera Status window
shows which filter is currently in position, and this information is
recorded with images when they are captured. You can rename the
filters using the Filter Setup command. If you have removed the
filter wheel from your camera or removed the filter from the
magazine you can select the None command in the Filter menu. The
None command doesn't position the filter wheel, it just tells the
software that you aren't using a filter at the moment. If you run
without filters for a period of time you should use the Filter Setup
command to select the "None" type of filter wheel. Use the Setup
command in the Filter menu to tell the CCDOPS software which
filter position contains which filter. You do not have to follow the
default RGB positions.
Vignetting
The increased length of the filter wheel assembly will cause
vignetting for fast systems (those with low F numbers such as
F/3.3). The vignetting will be worse for the larger ST-8, ST-9, ST-10
with their relatively large CCDs versus the ST-7. Vignetting will
show up as a fall off in the sky background at the edges of the field
of view. Flat fielding greatly reduces the troublesome effects of
vignetting. If a nosepiece is used to attach the camera and filter
wheel combination to the telescope, the 2" nosepiece should be used
if possible. SCT users should use the optional T-thread Visual Back
to make a more secure attachment.
First Use
Before starting an observing session, particularly after
equipment changes / modifications, test the filter wheel and camera
