05-04-2018, 05:55 PM
"When the shear pins break, what does it rest on ? Is it protected from multiple quakes after that?
Is it resting on a more forgiving surface until' it can be remounted with new pins ?
Will all this jostling around cause errors in data or break up consistency ?
ETA:
For anyone wondering:
http://www.ukirt.hawaii.edu/telescope/sky_access.html"
The telescope mount (the whole structure that supports the mirror) rests on large ball-bearings. It's finely balanced and am not concerned too much about damage to the structure, but the shear pins breaking indicates the whole thing has shifted slightly (probably a millimeter or less). It's still on the bearings though. Unfortunately, a millimeter of shift at that point means we'll be way off when pointing at targets and will have to recalibrate the telescope. It'll be virtually impossible to carry out science observations until that's done as we won't know what we're pointing at.
When new pins need to be inserted, the telescope is literally jacked up and new pins inserted. There's a video about this taken from an astronomer many years ago (from memory, he gets things wrong when he says the pins hold the telescope in place - they don't, they just tell us if something moved).
https://youtu.be/yn5pHqENfJA
PS. If you watch the video from about the 5-minute part, you'll see why I don't want people replacing the shear pins when there's a good chance of another severe earthquake.
Is it resting on a more forgiving surface until' it can be remounted with new pins ?
Will all this jostling around cause errors in data or break up consistency ?
ETA:
For anyone wondering:
http://www.ukirt.hawaii.edu/telescope/sky_access.html"
The telescope mount (the whole structure that supports the mirror) rests on large ball-bearings. It's finely balanced and am not concerned too much about damage to the structure, but the shear pins breaking indicates the whole thing has shifted slightly (probably a millimeter or less). It's still on the bearings though. Unfortunately, a millimeter of shift at that point means we'll be way off when pointing at targets and will have to recalibrate the telescope. It'll be virtually impossible to carry out science observations until that's done as we won't know what we're pointing at.
When new pins need to be inserted, the telescope is literally jacked up and new pins inserted. There's a video about this taken from an astronomer many years ago (from memory, he gets things wrong when he says the pins hold the telescope in place - they don't, they just tell us if something moved).
https://youtu.be/yn5pHqENfJA
PS. If you watch the video from about the 5-minute part, you'll see why I don't want people replacing the shear pins when there's a good chance of another severe earthquake.