Reports until 09:54, Monday 26 January 2026
H1 PSL
ryan.short@LIGO.ORG - posted 09:54, Monday 26 January 2026 (88891)
PSL FSS RefCav Remote Alignment Tweak

This morning, I finally got around to realigning the RefCav after having watched its transmitted power drop significantly over the past several weeks, which doesn't surprise me with the changing weather. Using the picomotors upstream of the RefCav, and with the ISS enabled, I was able to greatly improve the signal on the TPD from 250mV to 500mV. This isn't quite as high as we've seen it after a good on-table alignment, so perhaps sometime in the future we will go into the enclosure and touch up the alignment there.

Attaching a picture of the quad video display post-alignment for posterity; before I started the RefCav reflected spot looked like two distinct lobes vertically next to each other, showing a very obvious misalignment in pitch (which I found to be the area of most improvement when using the picos).

Images attached to this report