SX QC and Pyramid co-pointing

We switch on the AGW and we configure it to be used with IS. FW1: 600-1000, we center on QC.

Board

-72.3

-50.1

35.0

Then we offset the TipTilt mirror by [2.2; 2.1]V, corresponding to the position measured in August 2015 during the QC alignment.

We measure the range of FW2 positions that do not vignette the QC beam: -0.02 - 0.13 filter positions. Instead the range of positions for FW2 that are able to feed the QC are: -0.015 - 0.015.

Since FW2 has 6 filters (60deg/filter) we get that 1milli filter corresponds to about 1mrad of tilt. The distance between QC and FW2 is about 150mm, so 1mfilter corresponds to about 80mas on-sky. Considering a positioning accuracy of 3mfilter for the FW2 this corresponds to 150mas of co-pointing error on-sky due to FW2 histeresys. A lambda/D on the Pyramid tip corresponds to about 30mas. The co-pointing error due to FW2 misplacement is about 5 lambda/D, comparable with the modulation diameter...

We scan various LUCI rotator positions and we check the modulation offset that allow to co-point PYR and QC. Moreover we check if moving FW2 we can minimize the co-pointing offset:

Rot	PI	FW2	Notes
345	[1.6; 4.4]	-0.002
	[1.7; 4.7]	[0.0]
	[0.5; >5.0]	0.003
	[2.2; 2.1]	-0.007
255	[2.2; 2.1]	0.003	we've lost 1/3 of light wrt -0.007
165	[0.6; 3.0]	-0.007	we cannot co-point with [2.2; 2.1]
75	[-0.80; 0.3]	-0.007	we cannot co-point with [2.2; 2.1]

We notice that flux on QC is increasing with FW2 position going from + to -: for example we have 100% flux at -0.007, 125% at -0.015 and 50% at 0.005. This effect is independent of rotator position.

We test the QC in closed loop from AARB w/o disturb. Co-point in truth sensing seems to work. Working at 75deg of LUCI rotator angle we have a co-pointing offset of [-0.5, 0.5]V.

We test the QC also with 1" equivalent disturb, using old (December) rec:

TN	AO Gain	Res. WF [nm rms]	AO rec	DIMM ["]	JCL	PCL	Notes
20160311_191232	0.5,0.4,0.3	93.5948	20151213_063700	-1	T	F

Since the ASM is skipping when 1" disturb is applied we try to reduce the alignment coma using the haxapod. After optimization:

SX Hexa	4.65	1.77	-0.71	8	-107
Board	-75	-48	45

We close again with 1" disturb:

TN	AO Gain	Res. WF [nm rms]	AO rec	DIMM ["]	JCL	PCL	Notes
20160311_193515	2,0.45,0.45	105.398	20160310_213600	-1	T	F
20160311_193631	2,0.45,0.45	102.52	20160310_213600	-1	T	F
20160311_193651	2,0.45,0.45	106.676	20160310_213600	-1	T	F

Since co-pointing can work between -15 and 165deg of LUCI rotator we try to close the loop on QC in these positions, checking the co-pointing convergence:

Rot	Board	PI
75	[-75; 48]	[2.2; 2.1]
30	[-74.5; -50]	[1.3; 1.6]
0	[-74.4; - 51.5]	[2.3; 2.0]
-15	[-74.5; -52.5]	[3.0; 2.1]
165	[-79.4; -49.6]	[0.77; -3.0]

While closing loop at different rotator angles we also acquired snapshots:

TN	AO Gain	Res. WF [nm rms]	AO rec	DIMM ["]	JCL	PCL	Notes
20160311_193753	2,0.45,0.45	98.1175	20160310_213600	-1	T	F	75deg
20160311_193923	2,0.45,0.45	98.7126	20160310_213600	-1	T	F
20160311_213447	1,0.4,0.3	68.7564	20160310_213600	-1	T	F	0deg
20160311_213516	1,0.4,0.3	64.1665	20160310_213600	-1	T	F
20160311_214225	0.2,0.1,0.05	78.831	20160310_213600	-1	T	F	-15deg
20160311_214248	0.2,0.1,0.05	84.0563	20160310_213600	-1	T	F
20160311_215056	1,0.4,0.3	58.2939	20160310_213600	-1	T	F	165deg
20160311_215114	1,0.4,0.3	59.6251	20160310_213600	-1	T	F

Then we close with a 1" disturb, source is equivalent to mag10 star:

TN	AO Gain	Res. WF [nm rms]	AO rec	DIMM ["]	JCL	PCL	Notes
20160311_215502	1,0.4,0.3	72.7737	20160310_213600	-1	T	F
20160311_215815	1,0.4,0.3	75.9512	20160310_213600	-1	T	F
20160311_215910	1,0.4,0.3	75.5551	20160310_213600	-1	T	F
20160311_220025	1,0.4,0.3	77.5041	20160310_213600	-1	T	F

Then we reduce the flux to test the truth sensig at magnitude 16:

TN	AO Gain	Res. WF [nm rms]	AO rec	DIMM ["]	JCL	PCL	Notes
20160311_225330	0.5,0.3,0.1	63.924	20160310_213600	-1	T	F	w/o dist
20160311_225359	0.5,0.3,0.1	65.7635	20160310_213600	-1	T	F
20160311_225531	1,0.4,0.4	83.072	20160310_213600	-1	T	F	1" dist
20160311_225551	1,0.4,0.4	85.7034	20160310_213600	-1	T	F
20160311_225619	1,0.4,0.4	86.4308	20160310_213600	-1	T	F

WhiteLightSource SX to Pyramid magnitude calibration

We scan the white light source aperture and we check the equivalent magnitude on the pyramid:

WLS steps	303	80	70	65	60	55	50	45	40
Pyr mag (600-1000)	-	10	11	11.5	13.5	15	16	17	18
Pyr mag (90-10)	11.5	12	13	13.5	15

QC hot spot on CCD47

We checked the CCD47 pixel corresponding to QC tip: FW1: silver mirror (#4), FW2: empty (#1) -> [34; 42] @ BIN16.

LgswUnitDx to CalUnit alignment

We aligned the LgswUnitDx to the calibration unit. We ended up to a limit position were the decenter Y of the hexapod was hitting the limit; we have less coma with respect to yesterday, but not null

DX Hexa	-5.95	-7.6	0.95	145	-20	0

We feed all the three Lgsw and we acquired a 10 modes interaction matrix with KL_v21

IM	REC	COMBO
20160311_204825	20160311_205800	20160311_205900

We closed the AO loop without disturbance with the jitter initial position 20160311_210436 and the pupil motors in :

BEAM	X	Y
BLUE	415	515
YELLOW	205	370
RED	435	345

LgswUnitDx FoV measurement

We do a sweep of +/-6" in 11 steps and we measured the FOV center of the BLUE

We do a sweep of +/-6" in 11 steps around the RED FOV center estimated from the previous image and we measured the FOV center of the RED

We updated the procedure in order to obtain a squared grid of the hexapod movements. We did a sweep of +/-8" in 7 steps around the YELLOW FOV center estimated from the first image and we measured the FOV center of the YELLOW;

BEAM	[Rx; Ry]
Blue	[138.6; -20.1]
Yellow	[142.12; -19.16]
Red	[147; -24]

We defined a new subapertures set to align the center of the FOV to the center of the subapertures and minimize the jitter offset. The new set is 20160311_234700.

Since we cannot shift the BLUE subapertures in the x direction, we change the pointing moving the hexapod The new BLUE hexapod position is

DX Hexa	-5.95	-7.6	0.95	141	-22	1.41

We also changed the BLUE pupil motor position

BEAM	X	Y
BLUE	410	530
YELLOW	205	370
RED	435	345

PockelsCellsTransmission test

Side	PCT
DX
SX

TipTiltSystemSx IM recording

We recorded a new IM for the SX QC using the AGW IS.

Board

-72.8

-49.9

25

• IM: 20160312_030023

The scan seems not very good, it is not passing by the center of the QC, so we refine the source centering on the QC and acquire a new IM. QC speed is 500Hz, Pyramid (TS) speed is 100Hz.

Board

-72.82

-49.85

25

IM	REC	COMBO REC
20160312_030807	20160312_030900	20160312_032600

We change FW1 to 600-1000 to be able to ramp up the IS and acquire the IM at 1kHz: 20160312_032258. But this new one is worse because we have a double spot on QC.

-- TommasoMazzoni - 12 Mar 2016