zero second exposure

[jimmer]

Hello could you tell me please how to take a zero second exposure (newbie):rofl:

[pluto]

Hi Jim,
I assume you mean zero seconds as in under 1 second?
Because a zero second exposure, as in no exposure time at all, isn't possible.
Are you using a DSLR?

[[1ponders]]

Hi Jim.

I gather you are trying to take a bias frame. How you do that depends on the camera. If you are using a dedicated astro CCD then the program that operates the camera should allow you to take 0 length or bias frames.

If you are using a DSLR then you will simply have to set your camera manually to its fastest possible shot (ie 1/4000 sec).

If for webcam (not sure why you'd need it) then the same applies as for DSLR, just the fastest exposure you can achieve.

hth