I am considering LRTimelapse PRO Timer 3 for experiments (~1h) in which I would need to sync images from a conventional
Lumix G9 camera to a FLIR thermal camera (which is under the control of a PC) using frame rates ~2-3 Hz
(the maximum internal frame rate of the G9 is 1Hz).

I have seen
https://forum.lrtimelapse.com/Forum-lrt-...on-english
and worried.

Is it possible to set the time by directly reading from the internet or GPS? In that case, I think that setting the time before each experiment
would be sufficient.

Could you please clarify how time setting is performed in LRTimelapse PRO Timer 3 ?

Hi, you cannot synchronize the internal clock of the LRTimelapse PRO Timer with external sources, I'm sorry. You need to set the date/time manually.
But your use case is not really clear to me.

What you can do, is trigger 2 cameras synchronously with the LRT PT just by connecting them to the 2 release ports.

Please clarify what you want to do.

We want to record a time lapse with a thermal camera and a conventional Lumix G7 camera.
The thermal camera is under the control of a dedicated PC or RPi, which time can be set through the internet. This camera acquires images
at ~10 Hz. The LRT intervalometer cannot be connected to this system.
We need to shoot the Lumix G7 at frame rates 2-3 Hz and need a time stamp that would let us sync the resulting images as much as possible with
the thermograms.
So it seems LRT cannot be used for this.
Having just a manual time set looks like a general drawback, although I am sure there are lots of nice applications for which a correct time stamp is not required.

The LRT Pro Timer is designed for general timelapse photography, but not for scientific applications.