In article om,
murlockc wrote:

Hi everyone!
I am trying to observe the sun using a CMOS chip, but I get the
following problem: when the neutral density located in front of the
sensor is too low, a "black hole" appears at the center of the sun.
Have you already met this kind of problem? Is it a known phenomenon? I
have tried to search for information concerning this type of problem on
the web, but I did not find any clues how to solve it.
It seems that this "black sun" can also appear with CCD chips.

Is there a way to solve it without using post image processing?

Cedric


It would depend on which CMOS sensor your talking about.

I know that Zoran CMOS sensors had that issue and when we looked at
light bulbs the filament would appear black. Changing the intensity of
the gains helped somewhat but it was an electronics issue and had to be
resolved post.

HTH..

Milton Aupperle
http://www.outcastsoft.com/AstroImages/AstroIndex.html