High precision time measurement

gajowy

Hi,

For certain astrophotography purposes I need very precise time registration (~0.001s). So, my code is like follows:

time_start = CurrentTime();

startExposure(); // <-- function from ASI SDK

do {} while (getExpStatus() == EXP_WORKING);

time_end = CurrentTime();

The questions are how much time is between:

a) calling startExposure() and first photon is collected,

b) last photon collected and getExpStatus() returns EXP_SUCCESS.

Even if it's impossible to give precise numbers (?) maybe there is any method for estimation?

Kind Regards,

Gajowy

Sam@ZWO

the delay would be around more than 100ms

gajowy

Sam wrote:
the delay would be around more than 100ms

Thank you for response. I guess it's for question b). What about a) ?

t0 = CurrentTime();
startExposure();
t1 = CurrentTime();

I found t1-t0 is as small as 0.0002 sec (Windows7/i5-6200CPU/USB3).

Can I assume that actual photon collection starts within these 0.0002 s ?

Kind Regards,

Gajowy

Sam@ZWO

Gajowy wrote:
Sam wrote:the delay would be around more than 100ms

Thank you for response. I guess it's for question b). What about a) ?
t0 = CurrentTime();
startExposure();
t1 = CurrentTime();
I found t1-t0 is as small as 0.0002 sec (Windows7/i5-6200CPU/USB3).

Can I assume that actual photon collection starts within these 0.0002 s ?

Kind Regards,

Gajowy

startExp only send one signal, but the delay need more than 100ms

gajowy

startExp only send one signal, but the delay need more than 100ms

That's poor :(. Please consider implementation a way to register actual time of exposure start (and end) with higher precision. Maybe additional camera status?

For some kind of observations (occultations, speedy NEOs astrometry) 0.1s is not enogh.

Thank you for informations!

Kind regards,

Gajowy

einari

Have you looked at competitors product ?

https://www.cyclopsoptics.com/cooled-camera/qhy174m-gps-coldmos/