This webpage contains data on the reflectivity measurements of the INT primary mirror.

Reflectivity results - INT Primary Mirror

2023

Date

Dome     °C/ %RH

Reflectivity
(624 nm)

Scaterring
("Dust" %, 624 nm)

File

Notes

26/04/2024
10/10
89%
 3% 
20240422_INTM1_CO2
 Dry air and CO2 cleaning; streaks remain 

2023

Date

Reflectivity
(624 nm)

Scaterring
("Dust" %, 624 nm)

File

Notes

06/09/2023
90.20%
 <1% 
20230906_INTM1_Aluminized
Best result in all of 2023 coatings, see Report plot. 
Max 94%, gain 10% in UV, 2% in IR.
24/01/2023
87.1%
6% 
20230124_INTM1_Wash
Improvement from wash 6%, similar to previous. 
Large streaked stains remaining thought to be oil.
10/01/2023
77.1%
17.2% 
20230113_INTM1_check
First measurements since return of CT7; had to be repeated. 
Values are comparable to previous minima,
but water streaks reduce %R by 5% more.

2021

Date

Reflectivity
(624 nm)

Scaterring
("Dust" %, 624 nm)

File

Notes

22/10/2021
86.6%
7.1% 
20211026_INTM1_wash
Water Wash. CT7 calibration as previous. Improved ~6%
01/08/2021
83.4%
13.4% 
20210801_INTMs_CO2
Dry air followed by CO2 cleaning, 9% improvement. 
CT7 Memory card fault. Calibration altered
<0.3% is 5 bands, < 1.2% in red

2020

Date

Time

Reflectivity
(624 nm)

Scaterring
("Dust", %, 624 nm)

RMS (Å)

File

Notes

05/03/2020
 
84.5%
11.8% 
n/a 
20200305_INTM1_CO2
Compressed air improved %R; after CO2, %R up 7%

2019

Date

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity
(624 nm)

CT7 model scaterring
(@624 nm)

RMS (Å)

File

Notes

07/02/2019
n/a
n/a
87.7%
4.8% 
n/a 
20190207_INTM1_check
Spontaneous "recovery", 2% R in blue
22/01/2019
 
n/a
n/a
86.9%
5.6% 
20190122_INTM1_Wash
0.5 to 2% lower than Wash in 9/2017

2018

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity
(624 nm)

CT7 model scaterring
(@624 nm)

RMS (Å)

File

Notes

17/08/2018
 
n/a
n/a
83.3%
10.8% 
n/a 
20180817_INTM1_CO2

2017

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity
(624 nm)

CT7 model scaterring
(@624 nm)

RMS (Å)

File

Notes

05/10/2017
 
n/a
n/a
88.4%
4.3% 
n/a 
20171005_INTM1_Wash
Rain and dust gathered in August & September were sucessfully removed by Washing. Changes of ~6% in %R and 10% in Scattering, which accumulated 2% net loss. Oil leak should be fixed before Aluminisation.
28/07/2017
 
n/a
n/a
87.4%
5.7% 
n/a 
20170728_INTM1_CO2
Follows 2 calimas a week apart. Aligal, small flakes. Cleaned to level of April.
30/06/2017
 
n/a
n/a
87.5%
5.3% 
n/a 
20170630_INTM1_CO2
Snowflakes very small and high flow rate but improved to better than levels of April.
19/04/2017
 
n/a
n/a
86.5%
6.3% 
n/a 
20170223_INTM1_check
2.2% R loss since water wash. CO2 not programmed due to high humidity.
23/02/2017
 
2.8 E-03
4.8 E-04
88.1%
3.9% 
48 
20170223_INTM1_Wash
Washing recovered > 7% accumulated loss of %R, restoring it to within 2% of fresh aluminium levels.
23/02/2017
 
N/A
N/A
80.4%
N/A
N/A 
20170223_INTM1_Wash
Before wash, %R reached the lowest levels measured since 2012. The mirror showed small but widespread spotting, probably caused by light rain or fog, but no drip stains. This caused the dust to adhere, making CO2 ineffective and washing necessary.

2016

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

28/07/2016
 
n/a
n/a
87% (CT7)
n/a 
20160728_INTM1_Aligal
Even after cleaning with Aligal-CO2, there is an accumulated loss of 2% reflectivity w.r.t January that has not been recovered. Aluminizing was Pending over this period, but not carried out.
28/01/2016
 
3.1 E-03
1.0 E-03
89% (CT7)
84% (uScan)
44.2  
20160128_NewCO2_testCoudeINTM1
Results from using cheaper CO2 on
recently washed INT primary and on Coude mirror

2015

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

26/11/2015
 
n/a
n/a
89% (CT7)
n/a  
20151126_INTM1_Wash
Water wash. Only CT7 data.
Reflectivity increase 
5% average. 

2014

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

2/10/2014
 
1.7 E-03
2.4 E-04
89% (CT7)
85% (uScan)
28.2  
20141002_INTM1_Wash.pdf
Water/IPA wash successful.
Rain 2 weeks later
increased scattering

2013

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

18/12/2013
 
1.9 E-03
3.2 E-04
0.857 ± 0.001
37.5  
20131218_INTM1_Wash
Measurements after wash only

2012

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

26/9/2012
 
8.2 E-05
2.0 E-05
0.867 (SMS)
88% (CT7, 624nm)
81.8  
20121004_INTM1_Alu.pdf
Aluminization, CT7 data, reported 2017
16/05/2012
 
1.0 E-02
2.39 E-03
0.8150 ± 0.003
81.8  
20120516_INTM1_CO2cleaning.pdf
After CO2 cleaning
16/05/2012
 
1.7 E-02
9.1 E-03
0.783 ± 0.003
98.6  
20120506_INTM1_Co2cleaning
Before CO2 cleaning

2011

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

24/11/2011
 
1.5  E-02
5.6  E-03
0.800 ± 0.003
100.0  
20111124_INTM1_Wash
Before water washing.

2010

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

16/07/2010
 
6.2  E-03
1.3  E-03
0.834 ∓ 0.002
65.0  
INT_CO2results15July.pdf
After CO2 cleaning of the INT primary mirror. Reflectivity much improved but scattering remains a little high.
15/07/2010
 
1.17 E-02
7.1  E-03
0.803 ∓ 0.009
80.1  
INT_CO2results15July.pdf
Before CO2 cleaning of the INT primary mirror
05/04/2010
 
4.444E-03
9.521E-04
0.822
54.169
20100405INT.pdf
After CO2 cleaning of the INT primary mirror
05/04/2010
 
1.391E-02
3.382E-03
0.784
94.171
20100405INT.pdf
Before CO2 cleaning of the INT primary mirror
19/01/2010
 
1.668E-03
3.096E-03
0.825
35.661
20100119INT.pdf
After washing of the INT primary mirror
Humidity 50%
19/01/2010
 
1.487E-02
5.454E-03
0.796
93.460
20100119INT.pdf
Before washing of the INT primary mirror
Humidity 50%
12/01/2010
 
1.547E-02
4.654E-03
0.781
99.395
20100112INT.pdf
After CO2 cleaning of the INT primary mirror
Humidity 0% - no improvement due to low humidity?
12/01/2010
 
1.456E-02
5.039E-03
0.778
94.388
20100112INT.pdf
Before CO2 cleaning of the INT primary mirror
Humidity 0% - no improvement due to low humidity?

2009

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

07/09/2009
 
4.554E-03
1.876E-03
0.870
50.897
20090907INT.pdf
After CO2 cleaning of the INT primary mirror
07/09/2009
 
1.100E-02
6.485E-03
0.808
77.582
20090907INT.pdf
Before CO2 cleaning of the INT primary mirror
27/07/2009
 
6.350E-03
2.115E-03
0.815
61.367
20090727INT.pdf
After CO2 cleaning of the INT primary mirror
27/07/2009
 
1.568E-02
1.165E-02
0.753
95.825
20090727INT.pdf
Before CO2 cleaning of the INT primary mirror
11/02/2009
         
 
Aluminisation

2008

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

02/09/2008
 
2.387E-03
9.470E-04
0.832
36.308
20080603INT.pdf
After CO2 cleaning of the INT primary mirror
02/09/2008
 
8.625E-03
6.143E-03
0.784
69.362
20080603INT.pdf
Before CO2 cleaning of the INT primary mirror
03/06/2008
 
1.543E-03
5.856E-04
0.869
29.200
20080603INT.pdf
After CO2 cleaning of the INT primary mirror
03/06/2008
 
6.046E-03
5.518E-03
0.849
57.545
20080603INT.pdf
Before CO2 cleaning of the INT primary mirror
21/04/2008
 
2.428E-04
1.486E-04
0.872
10.960
20080421INTALU.pdf
Measured values after aluminising 
(the mirror was measured 4 days 
after the aluminising process)

2007

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

13/12/2007
 
4.128E-03
7.805E-03
0.872
50.462
20071213INT.pdf
After vapour washing
13/12/2007
 
1.697E-02
8.294E-03
0.822
96.456
20071213INT.pdf
Before vapour washing
04/10/2007
 
1.003E-02
3.175E-03
0.852
75.708
20071004INT.pdf
After CO2 cleaning
Also the file contains 
data on the scratches 
that was caused by the 
cover under the petals
04/10/2007
 
1.276E-02
5.669E-03
0.844
83.035
20071004INT.pdf
Before CO2 cleaning
24/07/2007
 
9.228E-03
2.908E-03
0.854
72.629
20070724INT.pdf
After CO2 cleaning
24/07/2007
 
1.072E-02
4.634E-03
0.843
76.389
20070724INT.pdf
Before CO2 cleaning
22/06/2007
 
8.745E-03
2.585E-03
0.842
65.633
20070622INT.pdf
After CO2 cleaning
22/06/2007
 
9.993E-03
4.350E-03
0.837
73.864
20070622INT.pdf
Before CO2 cleaning
18/01/2007
 
5.073E-03
1.477E-03
0.871
53.833
20070118INT.pdf
After CO2 cleaning
18/01/2007
 
8.156E-03
3.867E-03
0.851
65.633
20070118INT.pdf
Before CO2 cleaning

2006

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

02/08/2006
09:08:21
2.82E-03
8.90E-04
0.8814
39.500
INTPA308.PRN
After CO2 cleaning
02/08/2006
08:41:45
4.91E-03
2.54E-03
0.8617
50.407
INTPB308.PRN
Before CO2 cleaning
21/06/2006
14:10:06
3.04E-03
1.06E-03
0.8597
40.851
INTPA216.PRN
After CO2 cleaning
21/06/2006
13:23:53
6.82E-03
4.59E-03
0.8265
60.258
INTPB216.PRN
Before CO2 cleaning
09/03/2006
10:50:52
2.19E-03
6.40E-04
0.8858
35.400
INTPA903.PRN
After CO2 cleaning
09/03/2006
10:28:58
3.38E-03
1.81E-03
0.8802
41.369
INTPB903.PRN
Before CO2 cleaning
25/01/2006
11:40:09
4.98E-03
1.81E-03
0.8839
51.676
INTP2501.PRN
 

2005

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

16/09/2005
 

 

 
 
 

 

CO2 Cleaned 16/06/2005 
no reflectivity data
11/08/2005
 

 

 
 
 

 

CO2 Cleaned 11/08/2005 
no reflectivity data
28/06/2005
 

 

 
 
 

 

CO2 Cleaned 28/06/2005 
no reflectivity data
25/05/2005
09:26:35
1.02E-04
3.94E-05
0.9189
8.050
INTPA255.PRN
After CO2 cleaning
23/05/2005
15:29:37
8.21E-03
3.93E-03
0.8084
67.790
INTPB235.PRN
Before CO2 cleaning
10/03/2005
13:14:48
3.91E-03
8.62E-04
0.8417
53.200
INTPA103.PRN
After CO2 cleaning
10/03/2005
12:43:57
7.43E-03
2.77E-03
0.8207
65.460
INTPB103.PRN
Before CO2 cleaning

2004

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

16/12/2004
15:40:17
7.87E-03
1.51E-03
0.8750
68.550
INTP1612.PRN
To humid to CO2 clean
27/10/2004
13:52:09
3.71E-03
5.65E-04
0.8813
54.625
INTPW1.PRN
Washing after
27/10/2004
10:34:25
7.43E-03
2.10E-03
0.8574
65.708
INTPWB27.PRN
Washing before
05/10/2004
10:34:39
5.70E-03
1.25E-03
0.8728
60.553
INTPA410.PRN
After CO2 cleaning
05/10/2004
09:46:08
9.17E-03
4.06E-03
0.8718
69.483
INTPB410.PRN
Before CO2 cleaning
31/08/2004
10:45:20
5.55E-03
1.26E-03
0.8796
59.313
INTPA318.PRN
After washing
31/08/2004
10:14:06
1.18E-02
6.93E-03
0.8545
78.163
INTPB318.PRN
Before washing
15/06/2004
09:44:54
4.51E-03
9.56E-04
0.8406
55.561
INTPA156.PRN
After CO2 cleaning
15/06/2004
09:13:25
7.41E-03
3.68E-03
0.8329
63.288
INTPB156.PRN
Before CO2 cleaning
18/03/2004
10:48:36
3.97E-03
7.79E-04
0.8367
52.925
INTPA183.PRN
After CO2 cleaning
18/03/2004
10:15:56
5.67E-03
2.33E-03
0.8267
56.471
INTPB183.PRN
Before CO2 cleaning
16/02/2004
11:26:27
3.68E-03
8.61E-04
0.8527
50.032
INTPA162.PRN
After CO2 cleaning
16/02/2004
10:55:15
8.64E-03
4.58E-03
0.8230
68.366
INTPB162.PRN
Before CO2 cleaning
15/01/2004
06:36:53
4.67E-03
2.05E-03
0.8784
49.459
INTP1501.PRN
 
15/01/2004
06:36:14
1.23E-02
4.82E-03
0.7918
87.111
INTP1501.PRN
 

2003

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

12/11/2003
05:36:54
3.09E-03
4.94E-04
0.8838
54.589
6.PRN
 
12/11/2003
04:40:37
2.68E-03
4.41E-04
0.7332
49.971
5.PRN
 
12/11/2003
03:19:25
7.12E-03
2.69E-03
0.7232
67.900
4.PRN
 
12/11/2003
03:15:29
5.25E-03
1.58E-03
0.7633
61.886
INT3.PRN
 
12/11/2003
02:18:31
2.97E-02
1.11E-02
0.7342
135.222
INTP12N2.PRN
 
12/11/2003
02:16:19
1.01E-02
4.95E-03
0.8450
73.116
INTP12N1.PRN
 
09/09/2003
01:55:38
4.31E-03
1.51E-03
0.8684
48.970
INTP909.PRN
 
20/08/2003
02:55:28
3.80E-03
1.00E-03
0.9026
46.815
INTPA208.PRN
 
20/08/2003
02:09:10
1.04E-02
6.53E-03
0.8648
72.686
INTPB208.PRN
 
25/07/2003
 
 
 
 
 

 

Cleaned 13/06/2003 
no reflectivity data
13/06/2003
 
 
 
 
 

 

Cleaned 25/07/2003 
no reflectivity data
20/05/2003
13:17:47
2.75E-03
4.71E-04
0.8801
45.431
INTPA205.PRN
CO2 cleaning
20/05/2003
10:19:40
1.36E-03
2.22E-04
0.8842
34.400
BBBB.PRN
after complete washing
20/05/2003
10:09:14
8.19E-03
2.00E-03
0.8660
71.100
AAAA.PRN
test with depping + soap
20/05/2003
09:01:35
1.28E-02
3.80E-03
0.8515
86.806
INTPB205.PRN
 
28/03/2003
11:32:49
1.18E-02
2.87E-03
0.8499
86.284
INTP2803.PRN
 
03/03/2003
11:39:12
1.17E-02
3.00E-03
0.8202
86.800
INTPA033.PRN
 
03/03/2003
10:49:32
1.33E-02
5.18E-03
0.8296
86.652
INTPB033.PRN
 
03/01/2003
11:27:44
1.15E-02
2.77E-03
0.8386
86.026
INTP0301.PRN
 

2002

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

19/12/2002
12:00:38
1.57E-02
1.95E-03
0.8256
130.040
INTPA19D.PRN
 
19/12/2002
11:37:15
1.64E-02
2.90E-03
0.8215
114.905
INTPB19D.PRN
 
28/11/2002
11:29:16
1.23E-02
1.86E-03
0.8300
103.945
INTPA28N.PRN
 
28/11/2002
11:05:10
1.32E-02
2.61E-03
0.8302
97.895
INTPB28N.PRN
 
15/11/2002
10:08:43
1.07E-02
2.59E-03
0.8125
84.689
INTP1411.PRN
 
30/10/2002
09:59:29
8.90E-03
2.32E-03
0.8513
73.748
INTPA30.PRN
 
30/10/2002
09:31:13
1.08E-02
4.28E-03
0.8390
77.508
INTPB30.PRN
 
08/10/2002
10:55:07
1.12E-02
4.36E-03
0.8397
78.710
INTP0810.PRN
 
25/09/2002
10:14:19
8.31E-03
2.26E-03
0.8501
70.772
INTPA259.PRN
 
25/09/2002
09:56:39
1.05E-02
4.00E-03
0.8358
76.864
INTPB259.PRN
 
13/09/2002
10:17:33
9.50E-03
3.48E-03
0.8521
72.575
INTP1309.PRN
 
16/08/2002
11:06:25
7.72E-03
2.16E-03
0.8591
67.727
INTPA168.PRN
 
16/08/2002
10:37:13
1.19E-02
5.23E-03
0.8029
82.250
INTPB168.PRN
 
12/07/2002
09:23:29
8.54E-03
2.39E-03
0.8546
71.041
INTPA127.PRN
 
08/07/2002
09:58:36
9.33E-03
3.88E-03
0.8416
71.467
INTP807.PRN
 
31/05/2002
10:08:01
8.22E-03
2.36E-03
0.8377
70.294
INTPA315.PRN
 
31/05/2002
09:27:38
1.04E-02
4.16E-03
0.8299
76.262
INTPB315.PRN
 
26/04/2002
08:44:39
9.14E-03
2.44E-03
0.8364
75.118
INTPA264.PRN
 
26/04/2002
08:21:58
1.96E-02
1.17E-02
0.7852
105.250
INTPB264.PRN
 
16/04/2002
09:28:13
1.65E-02
8.36E-03
0.7771
97.764
INTP1604.PRN
 

2001

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

05/11/2001
11:27:29
8.44E-03
2.77E-03
0.8218
70.826
INTP511.PRN
 
16/10/2001
09:05:39
6.47E-03
1.56E-03
0.7923
68.433
INTP1610.PRN
 
02/10/2001
10:07:56
6.17E-03
1.64E-03
0.8279
62.538
INTPACO2_021001.PRN
 
02/10/2001
09:25:50
6.29E-03
2.21E-03
0.8749
58.270
INTPBCO2_021001.PRN
 
17/09/2001
09:18:11
5.12E-03
1.91E-03
0.8672
52.557
INTP1709.PRN
 
05/09/2001
10:32:33
5.10E-03
1.73E-03
0.8576
53.438
INTPA509.PRN
 
05/09/2001
10:10:08
7.54E-03
4.00E-03
0.8475
62.979
INTPB509.PRN
 
20/08/2001
09:39:27
6.35E-03
3.16E-03
0.8551
57.788
INTP2008.PRN
 
31/07/2001
10:04:24
3.62E-03
9.69E-04
0.8456
46.657
INTPACO3.PRN
 
31/07/2001
09:27:15
5.66E-03
3.27E-03
0.8456
54.512
INTPBCO3.PRN
 
05/07/2001
14:20:39
3.04E-03
8.71E-04
0.8758
41.633
INTP507A.PRN
 
05/07/2001
13:34:52
4.27E-03
2.00E-03
0.8862
46.669
INTP507B.PRN
 
05/06/2001
11:22:51
3.89E-03
1.28E-03
0.8713
45.580
INTPA506.PRN
 
05/06/2001
11:10:34
3.63E-03
1.97E-03
0.8773
43.138
INTPB506.PRN
 
23/05/2001
08:35:47
4.56E-03
2.39E-03
0.8958
47.176
INTP23-5.PRN
 
27/04/2001
09:18:01
2.94E-03
1.61E-03
0.9039
38.375
INT2740P.PRN
 
04/04/2001
13:02:40
2.61E-03
8.53E-04
0.8771
37.963
INTPACO2.PRN
 
04/04/2001
09:14:44
6.44E-03
4.41E-03
0.8628
57.319
INTPBCO2.PRN
 
20/03/2001
09:41:07
6.45E-03
4.17E-03
0.8657
56.927
INTP.PRN
 

2000

Date

Time

BSDF 0°,0°

(detector position)

BSDF 50°,180°

(detector position)

Reflectivity

RMS (Å)

File

Notes

11/10/2000
15:40:20
9.03E-05
4.65E-05
0.6590
91.300
INTCAL.PRN
 
11/10/2000
15:36:14
7.61E-05
2.88E-05
0.8765
6.408
INTALAFT.PRN
 
09/10/2000
16:46:37
3.00E-03
5.75E-04
0.7753
43.689
INTHO2AF.PRN
 
09/10/2000
16:30:34
2.33E-02
1.65E-02
0.7830
114.000
INTALBEF.PRN
 
10/05/2000
10:20:48
7.51E-03
1.83E-03
0.9069
66.466
INTRMS_2.PRN
 
10/05/2000
10:16:26
1.02E-02
3.30E-03
0.9105
73.686
INTCO23C.PRN
 
10/05/2000
10:11:41
8.01E-03
2.28E-03
0.8760
67.519
INT3CO2B.PRN
 
10/05/2000
10:08:13
9.75E-03
2.16E-03
0.8818
80.600
INT3CO2.PRN
 
29/03/2000
08:28:52
1.59E-02
9.85E-03
0.8196
92.530
INT293_B.PRN