Handbook for the SX-46 Full Frame camera Issue 2, 22
nd
March 2018
A stack of 6 x 10 minute H-alpha frames with a 150mm F7 APO. No darks or flats.
Other useful functions include the ability to ‘flood’ the CCD with light, followed by a CCD flush. This
can be useful for hiding ‘RBI’ (Residual Bulk Image) effects that may show up after imaging a bright
object. RBI consists of trapped charge in the silicon substrate that generates a ‘ghost’ image for some
time after the original exposure has completed, and it can be quite persistent. The ‘flood’ facility is in
the ‘Test’ menu and saturates the CCD with charge and then flushes away the contents of the pixels.
The bulk of the silicon retains an RBI charge pattern, but this is now uniform and no longer shows as a
recognisable image. The flood technique does increase the background noise to some degree and so it
should not be used for every image - just apply it when changing from one object to another, especially
if the first object was very bright (e.g. the moon). A flood of about 2 seconds is a good value to use.
Another useful feature in the ‘Test’ menu, is the ability to operate the shutter independently of imaging.
This is useful for opening the shutter for cleaning the camera window, or for cycling the shutter to
check for correct operation. The ‘Open’ and ‘Close’ buttons are self-explanatory, while the ‘Test’ box
will start a continuous ‘open / close’ cycle for as long as the box is enabled.
The Test menu also includes an SX filter wheel control function. It does not ‘auto change’ filters for
image sequences, but this may be added to future versions.