In article
,
BradGuth wrote:

The point is, 192 DB or better cmos imager should have no problems in
getting us a darn good look-see at Sirius C, that is unless you intend
to either exclude the IR spectrum or not otherwise use a narrow
bandpass or spectrum cutoff optical filter that would easily exclude
everything above 750 nm. I might consider a 750 to 1500 nm or
possibly even an 800 to 1200 nm bandpass as a good enough starting
point, of which by itself would eliminate the vast bulk of most
everything Sirius A and B have to offer.

The bandgap of Si is about 1200 nm, such dim objects are invisible.