[gaston (Gaston)]

Hello David,

I would suggest the SX lodestar as well. It is very sensitive with an extended NIR quantum efficient.
A very elegant, compact well-made design, I love mine.
Tests done to compare with the ORION starshoot (a CMOS sensor) have shown a bout 10x more signal for the lodestar versus the ORION (binned 2x2 to match the pixel sizes).
Also the lodestar is a 16 bits camera, not a 8 bits, with very small dark current even at ambient and powered on since a while.
It works perfectly with the ONAG. Have a look to the ONAG's NIR guiding page, the chip featured there is the lodestar one (Sony Exview series, ICX 429AL):

http://www.innovationsforesight.com/NIRGuiding.htm

In general the ONAG will have a NIR efficient around 0.6 to 1.0 magnitude less than the full spectrum with such chips.
For instance with my C11 at F/10 I usual can work with 9th magnitude stars at 1 second guider exposure. If you increase the exposure time to 2.5 s you get one more magnitude, or 10th.
Very low noise chip.

P.S: If you select this one you will need a C to T mount adapter since the lodestar uses a C mount thread system:

http://www.scopestuff.com/ss_c2tt.htm

Part #C2TT

Clear skies!

Gaston