Updates on the trip up the mountain
Christian hasn't responded, looks like we'll be out of it for a while
Andrew suggests we need to put this into a document with action items and the necessary steps to install TMS on Sx side
We need to tell Christian what we need to do and why
Reasonably urgently, we need to install a binocular TMS for the LBCr + LBCb
Need a schedule, white document, with our needs and puts action items into motion with
At the end of the day, Christian is going to make a management decision, but we can provide him with a reason to support our cause
If we can show some positive results on the Dx side, we may be able to have our action items put in place sooner
Andrew doesn't think we should make a resource request from Christian contingent upon our success on the Dx side
John suggests we should move to just ask Christian if we can just go ahead and install on Sx
Today, Ch. 11 alignment was reacquired, thanks to Leroy and John
However, we have to use the max gain to get 20% return from Ch. 11
Last night's data had Ch. 17 acting up
Andrew would like Ch. 17 to be looked at, as well
Heejoo mentioned that there is need for cleaning the fiber tips, especially for channels 11/17
To Andrew's mind, it is a fairly binodal situation; when there is poor return, the channels essentially just drop
When the telescope moves, the beam footprint from the retro walks off the collimator, effectively demanding an increase in the NA of the fiber collimator
We are really measuring contrast on the fiber
All channels currently looking at LBC right now are using the large collimators
Etalon spent time adjusting the tuning of the fiber collimators to get the maximal signal measurement on the contrast
Want big offsets (deliberately defocus the beam) the beam to spread out the energy on the retro
Andrew's updates on the solid Maksutov retro (like a Reed pupil relay + an Offner image relay)
Utilizes 30% BS on the buried surface to bounce light back out after inducing SA on the way in and removing on the way out
Beam retraces right on top of it's input
Also behaves like an solid Offner relay; able to use this to test the optical system
Able to get a null test using this system in the Offner configuration
This system actually flips the beam about the center of the aperture
Yang on ch. dropping handling
Working on it, would like to schedule a test in the later part of next week
If not possible, early part of the following week (end of Oct., start of Nov.)
Yang thinks he should have a test version relatively quickly
Andrew reminds us that last night's data has Ch. 17 dropping in and out throughout the night, and would like Yang to test his code with this data
Yang's understanding is that whenever a channel or multiple channels are dropped, a correction vector is to be applied
Can't say that he has 100% certainty about how the correction vector is designed
For some cases, we don't have to make any correction vector at all; could go back and make a reconstruction vector
Based on the mathematical file, correction vector def. as:
Whenever you have a dropped channel, compute pose changes with a vector using the correction to the dropped channel (from the last set of data) and subtract this from the pose change w/o the dropped channel included
Reconfigured matrix with last channel measurement (or reference vector, Yang's suggestion) applied to dropped channel
Difference between 9 ch. pose with substituted correction vector and 8 ch. pose w/o dropped channel used as actual pose
Andrew suggests that there is a difference between using the reference vector for correction and the last measured channel vector, and that it would be preferrable to use the last measured channel vector for correction
Andrew requests that, if we get test time, we also drive in astigmatism to work on fitting to mirror shape
John confirms that astigmatism was driven in today
+/- 5000 astig, and also spherical
Predicted change in Z, and a total change in length
Can see predicted change in diameter
The measurement of the terms is in the RMS WF
So 5000 astig corresponds to 5 microns
Plan is for Heejoo to schedule a test for about a week from now
Yang's next question
Suppose we never get a full 9 ch. measurement for an entire night
Do we still need to apply a correction?
Most of the time we have an 8 ch. and then we'll drop to 7 or 6 ch.
If able to get full 9 ch. vector, there are some combinations of possibilities
Use whatever the last working meas. was
What about if we are working with 7 channels and then we get a different set of 7 channels
Consider either skipping the measurement or configuring for a different set of the 7 channel
Good practice to work through all of the contingencies
Yang hoping for the software to work for all possible cases
Yang and Andrew to discuss this together to develop a procedural algorithm for testing the channel dropping handling
Trent will be presenting TMS at Industrial Affiliates Poster Session next week
Andrew would like to attend the test
Handover of telescopes is about 3:40 PM, about 2 hours before sunset
Heejoo suggests 1:00 PM ish for doing a test, and he prefers Tuesday (could be Friday)
Andrew happy to report that we are developing algorithms for channel dropping, and we want good results
Want to be able to say that it's working, at least a good prototype
For SPIE papers, good to talk about the various failures and problems
Yang will make an effort to give a summary of what the algorithm is doing for Andrew's paper
Updates on the trip up the mountain Christian hasn't responded, looks like we'll be out of it for a while
Andrew suggests we need to put this into a document with action items and the necessary steps to install TMS on Sx side We need to tell Christian what we need to do and why Reasonably urgently, we need to install a binocular TMS for the LBCr + LBCb Need a schedule, white document, with our needs and puts action items into motion with
At the end of the day, Christian is going to make a management decision, but we can provide him with a reason to support our cause
If we can show some positive results on the Dx side, we may be able to have our action items put in place sooner
Andrew doesn't think we should make a resource request from Christian contingent upon our success on the Dx side
John suggests we should move to just ask Christian if we can just go ahead and install on Sx
Today, Ch. 11 alignment was reacquired, thanks to Leroy and John However, we have to use the max gain to get 20% return from Ch. 11
Last night's data had Ch. 17 acting up Andrew would like Ch. 17 to be looked at, as well
Heejoo mentioned that there is need for cleaning the fiber tips, especially for channels 11/17
To Andrew's mind, it is a fairly binodal situation; when there is poor return, the channels essentially just drop When the telescope moves, the beam footprint from the retro walks off the collimator, effectively demanding an increase in the NA of the fiber collimator
We are really measuring contrast on the fiber
All channels currently looking at LBC right now are using the large collimators
Etalon spent time adjusting the tuning of the fiber collimators to get the maximal signal measurement on the contrast Want big offsets (deliberately defocus the beam) the beam to spread out the energy on the retro
Andrew's updates on the solid Maksutov retro (like a Reed pupil relay + an Offner image relay) Utilizes 30% BS on the buried surface to bounce light back out after inducing SA on the way in and removing on the way out Beam retraces right on top of it's input Also behaves like an solid Offner relay; able to use this to test the optical system Able to get a null test using this system in the Offner configuration This system actually flips the beam about the center of the aperture
Yang on ch. dropping handling Working on it, would like to schedule a test in the later part of next week If not possible, early part of the following week (end of Oct., start of Nov.) Yang thinks he should have a test version relatively quickly
Andrew reminds us that last night's data has Ch. 17 dropping in and out throughout the night, and would like Yang to test his code with this data
Yang's understanding is that whenever a channel or multiple channels are dropped, a correction vector is to be applied Can't say that he has 100% certainty about how the correction vector is designed For some cases, we don't have to make any correction vector at all; could go back and make a reconstruction vector Based on the mathematical file, correction vector def. as: Whenever you have a dropped channel, compute pose changes with a vector using the correction to the dropped channel (from the last set of data) and subtract this from the pose change w/o the dropped channel included
Reconfigured matrix with last channel measurement (or reference vector, Yang's suggestion) applied to dropped channel Difference between 9 ch. pose with substituted correction vector and 8 ch. pose w/o dropped channel used as actual pose
Andrew suggests that there is a difference between using the reference vector for correction and the last measured channel vector, and that it would be preferrable to use the last measured channel vector for correction
Andrew requests that, if we get test time, we also drive in astigmatism to work on fitting to mirror shape John confirms that astigmatism was driven in today +/- 5000 astig, and also spherical
Predicted change in Z, and a total change in length Can see predicted change in diameter
The measurement of the terms is in the RMS WF So 5000 astig corresponds to 5 microns
Plan is for Heejoo to schedule a test for about a week from now
Yang's next question Suppose we never get a full 9 ch. measurement for an entire night Do we still need to apply a correction? Most of the time we have an 8 ch. and then we'll drop to 7 or 6 ch. If able to get full 9 ch. vector, there are some combinations of possibilities
Use whatever the last working meas. was What about if we are working with 7 channels and then we get a different set of 7 channels Consider either skipping the measurement or configuring for a different set of the 7 channel
Good practice to work through all of the contingencies Yang hoping for the software to work for all possible cases
Yang and Andrew to discuss this together to develop a procedural algorithm for testing the channel dropping handling
Trent will be presenting TMS at Industrial Affiliates Poster Session next week
Andrew would like to attend the test
Handover of telescopes is about 3:40 PM, about 2 hours before sunset Heejoo suggests 1:00 PM ish for doing a test, and he prefers Tuesday (could be Friday)
Andrew happy to report that we are developing algorithms for channel dropping, and we want good results Want to be able to say that it's working, at least a good prototype For SPIE papers, good to talk about the various failures and problems
Yang will make an effort to give a summary of what the algorithm is doing for Andrew's paper