ASI174MM exposure issue

[janek950]

Hi,
when using ASI174MM camera and exposure times shorter then 500ms, everything is OK. However when I enter exposure time 500ms or more, there is (on average) 222ms dead time between exposures. No preprocessing, I've been playing with USB setting etc - no way. The same on two different computers. Both running W10 with latest updates, last camera driver 3.0.0.6 and last SharpCap. Is this a bug or some mystery setting can help ?
Thanks ...

[admin]

Hi,

For exposures below 500 ms the program runs the ZWO cameras in video mode – basically the camera is continually taking images. For longer exposures the program runs the cameras in a still camera mode where it requests each image to be captured separately. I'm sure that this is what is leading to the delay between exposures. Still camera mode is required for longer exposures as it is more robust when doing things like cancelling an exposure part way through in order to change the length of the next exposure.

Hope this helps, Robin

[janek950]

Hi,

this explanation clears situation - thanks. However as one of the purposes of the camera (for me) is timing occultations, such dead time is really unwanted. It's a pity but I have to use for camera control in those rare cases where >=0.5 second exposure time is needed, some other SW handling this in better way.

BTW - is this situation common also for other ASI cameras - like ASI1600 MM etc. ?

Many thanks, Jan

[admin]

Hi,

This is common to all ZWO cameras. There is no particular reason for the cut off point to be 0.5 seconds – I wouldn't be averse to increasing it to perhaps two seconds, although higher than that would probably start to be a problem with responsiveness when you change the exposure control. Would a two second exposure be sufficient?

Thanks, Robin

[janek950]

Hi,

yes, I think 2 seconds will be enough. That would be great !

jan