one reading from an angle finder isn’t accurate enough to mean anything.
first, what you do is orient it one way, zero it there, then spin 180 deg in place and record that angle.
then rotate 90 deg and repeat
that measure alone isn’t really meaningful. a sheet metal case isn’t going to be perfectly perpendicular to the gravity vector and doesn’t have to be.
but the change in measurement over 20 hrs is pretty damning.
I’ve also kept a record of the burn marks and they’ve drifted over 20 hrs.
i can realign it at any time but this seems pointless while the rate of drift is high. i did that one night last week during the rain and it was misaligned the next day
i can say this is NOT normal for Tarkin. it does not need regular realignment. there was a problem awhile back that traced to tracked down to a 3d printed #2 mirror mount that expanded too much as it was used and the mirror got hotter than expected too that’s been changed to aluminum, no issue there now.
there was only one other time in recent memory where it misaligned out of nowhere. it did occur when the weather changed and within a few days it rebounded and misaligned in the other direction, pretty much seemed to have returned back to where it was before and i was undoing the prior adjustment
i thought back to earlier times when the laser room’s temp was far from the 27C goal. hotter or colder… mostly hotter. wasn’t accompanied by alignment issues. and that includes cases where I’d expect the average temp through the entire thickness of the slab would have major temp changes too.
so, i don’t think slab temp matters. it’s the flooding saturating the ground under the slab, and then drying out again
Dorian has shown some weird alignment issues too, but it’s a smaller frame so it takes more to put the beam off the edge of a mirror
