FLI camera Bias Frames

Sequence Generator
1

I started taking some bias frames with a new FLI 16200 Microline and have it set to use the 2Hz capture mode. I noticed the bias frames using SGP are nearly devoid of data while the ones taking using TSX Camera Add on appear normal.

Any thoughts on why the Bias frames come out basically black (nothing appears even with stretching the data)?

rick
cardiofuse observatory

2

I double checked, as a matter of fact, there is no data there. Empty frames. I can set the exposure from 0.0 to .0000001 and I get a normal looking Bias. Thoughts?

3

Rick:

This is exactly the behavior that I encountered when I first got my FLI 16200. An exposure of 0 yields no data, whereas a small, finite exposure value will give you the bias signal that you want. This is different behavior than I had encountered with other cameras, where an exposure of 0 was interpreted as the minimum exposure for bias frames, but that’s not the case here. Using a small value is the way to go, and there ought to be no issues with it.

Best Regards,
Ben

4

Excellent and thank you for the response. My QSI690WSG can take a normal Bias with the exposure set to 0.0.

Something different in the FLI driver, I suppose (like not being able to use RBI settings).

I’m glad, at least that setting it to a minimal value accomplishes the same task. I’m wondering now if the shutter opens during this period of short duration Bias subs?

Kindly,

Rick.

5

I forgot to mention. I actually ended up shooting all the Bias frames (50) in TSXPro-Camera Add on and they came out as expected with a reasonable pedicle value.

6

No, the shutter doesn’t open when taking a bias frame (and, of course, it couldn’t possibly physically open for such a short duration anyway!) In this respect it’s just like taking a longer duration dark. No shutter action here.

As for RBI settings, I have put in a request for the SGP folks to add this to their driver. You may wish to throw in your opinion as well to let them know there is more interest in this feature. The jury is still out whether or not RBI flushing is always required, when it’s required, etc., but it would sure be good to have the capability through SGP in order to exercise the option, run tests, etc.

Ben