At this point I have reviewed the only video i can find of the time of his hand signal.
The point in time is when he is seated, awaiting his turn for the leak-check of his suit, (helmet and gloves will be fitted, hence his skull cap is ready, and his blue ventilation box is by his side).
His commander (Sergei Prokopyev) is undergoing the test, his ...
I'm thinking it is not to do with the LED lighting system at all, but rather the crew having fun.
There is a single hard light behind the subjects in all of the related photos i have seen.
The photos are harshly processed in order to bring out the colors more.
The most numerous brand of camera on the station is the Nikon DSLR (IIRC chosen for its radiation ...
Pretty much as my answer to a related question:
As part of the experiment, the crew of the ISS are subjected to the Dynamic Lighting Schedule:
Have the astronauts settled on a white or near-white setting ?
Pre-programmed and pre-planned with 3 lighting values:
Three pre-determined light settings are envisaged for use in different operational ...
Until someone has a better answer, I did briefly look at this some time ago when I saw that they had installed adjustable internal lighting.
It also is part of an on going experiment - Solid State Lighting Countermeasures, that started in 2016 through to at least 2019, though results are not yet available.
DART and EXP-55 are not the only two planned uses, in fact, ROSA will be used for many more missions.
According to Wikipedia's Roll-Out Solar Array Applications, iROSA (the scaled-up version of ROSA) will be launched on SpaceX's CRS-22, CRS-25, and CRS-26. The new solar arrays will be positioned in front of six of the current arrays and will use the existing ...
Just to have an idea of the order of magnitude:
"Time dilation explains why two working clocks will report different times after different accelerations. For example, time goes slower at the ISS, lagging approximately 0.01 seconds for every 12 Earth months passed."
Similarly, between Earth surface (1 ...