ASI174 used for occultations - timeing ?

[TimHaymes]

Hi Robin/All,
If i use this camera and Tangra for determining an occultation (mid-frame) time, and i have V 4.1.1x...
Do i select "end of frame" time setting in Tangra ? The time stamp is applied by the computer clock in this case.

I ask the question because im not sure if the SER time stamps are in some way different in V4.1 compared to 4.0.
With 4.0.9x the end-of-frame was the correct selection.

Second question: What does the on-screen (on frame) time represent in V4.1.1x ?

Many thanks

Tim
(Abingdon)

[admin]

Hi Tim,

the current implementation of SER file timestamps in SharpCap 4.1 is as follows

* If the camera has onboard GPS (QHY/Moravian have models with this) and it is active/locked: the GPS time for the frame start is used
* Other cameras where SharpCap knows the exposure (almost all cameras) : the estimated start time is used - this is the time the frame was received by SharpCap less the known exposure
* Exposure is unknown : the estimated end time is used - this is the time the frame was received by SharpCap.

Note that without a separate timing source, it's impossible to know how long the delay is between the camera capturing the frame and SharpCap receiving it. In video mode the camera may be buffering one or more frames, so the images received by SharpCap may be 'behind'. If you are running a ZWO camera at exposures of 2s or above, SharpCap runs the camera internally in still mode, avoiding this problem.

As for the in-frame timestamp, it now uses the same rules as for SER file timestamps as outlined above.

cheers,

Robin

[TimHaymes]

Thank-you Robin
Tim