EFOSC2 

ESO Faint Object Spectrograph and Camera
 
 
  
Photometric Zero Points for EFOSC2 with CCD#40: Full Summary

Until June 2000 the mean La Silla extinction values have been used for computing the coefficients.
From July 2001 the extinction values have been fitted as a free parameter as well.
 
U = u + ZP(u) + (U-B)* col(u) - Ext(u)*Airmass 
B = b + ZP(b) + (B-V)* col(b) - Ext(b)*Airmass 
V = v + ZP(v) + (B-V)* col(v) - Ext(v)*Airmass 
R = r + ZP(r) + (V-R)* col(r) - Ext(r)*Airmass 
I = i + ZP(i) + (V-R)* col(i) - Ext(i)*Airmass 

Note to observers: you can help us to maintain this database by sending your measurements. All contributions will be acknowledged.

February 21th, 1998

The data has been obtained during a photometric night. The telescope was closed at the end of the night because of to strong wind. The determinations are made from only 1 standard stars (RU_149).
Filters  Zero point  Color term 
24.129  0.063 
25.934 0.031 
25.961  0.024 
26.031  -0.003 

March 19th, 1998

The data has been obtained during a non-photometric night (some cirrus at the beginning, but the second half part was quiet cloudy). The determinations are made from only 1 standard stars (PG0942-02).
Filters  Zero point  Color term 
24.102  -0.019 
25.945  -0.052 
25.986  0.050 
26.066  -0.050 
25.259  -0.079 

April 18th, 1998

The data has been obtained during a partial photometric night (only the first half part). The determinations are made from 3 standard stars (RU_149, PG1047+003, PG1323-086 2 times). All the 4 measurements are in very good agreement.
Filters  Zero point  Color term 
24.356 +/- 0.015  0.059 +/- 0.005 
25.899 +/- 0.010  0.045 +/- 0.005 
26.023 +/- 0.007  0.037 +/- 0.005 
26.132 +/- 0.015  0.025 +/- 0.020 
25.294 +/- 0.020  -0.036 +/- 0.050 

August 24th, 1998

The data has been obtained during a non-photometric night (absoption of about ~0.2 but constant in all filters). The determinations are made from 1 standard stars (Tphe).
Filters  Zero point  Color term 
24.113  0.053 
25.680  0.052 
25.871  0.024 
25.981  0.014 
25.100  -0.044 

August 26th, 1998

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (Tphe, PG2331+05, Mark A 2 times). All the 4 measurements are in very good agreement.
Filters  Zero point  Color term 
24.315 +/- 0.025  0.056 +/- 0.008 
25.870 +/- 0.010  0.037 +/- 0.005 
25.956 +/- 0.010 0.040 +/- 0.006 
26.070 +/- 0.015  0.025 +/- 0.008 
25.220 +/- 0.010  -0.018 +/- 0.015 

August 28th, 1998

The data has been obtained during a perfectly photometric night. The determinations are made from 2 standard stars (Tphe, PG2331+05).
Filters  Zero point  Color term 
24.268 +/- 0.015  0.045 +/- 0.020 
25.853 +/- 0.020  0.020 +/- 0.015 
25.951 +/- 0.020  0.032 +/- 0.010 
26.060 +/- 0.015  0.027 +/- 0.015 
25.215 +/- 0.015  -0.010 +/- 0.025 

 August 29th, 1998

The data has been obtained during a perfectly photometric night. The determinations are made from 1 standard stars (Mark A).
Filters  Zero point  Color term 
24.286  0.042 
25.931  0.037 
25.963  0.046 
26.071  0.027 
25.203  -0.006 
Note that the Primary mirror (M1) has been washed beginning of December. Measurements shown that the reflectivity increase by about 5% (from 85% to 90%)

December 18th, 1998

The data has been obtained during a non-photometric night. For the 2 first standards the cirrus were very thin but for the third standard PG0918+02 the absorption was greater ... of the order of 0.2-0.3 magnitude. The determinations are made from 2 standard stars (Rubin149, Rubin152 and PG0918+02), each star observed 3 times with 3 different CCD places and 3 exposure times.
Filters  Zero point  Color term 
24.237 +/- 0.030  0.057 +/- 0.020 
25.882 +/- 0.020  0.040 +/- 0.015 
25.950 +/- 0.020  0.045 +/- 0.015 
26.100 +/- 0.020  0.005 +/- 0.015 
25.245 +/- 0.030  -0.017 +/- 0.030 
From the January 12th, 1999 measurements we should certainly add 0.05-0.10 magnitude to all the these values, the absorption seems no negligeable as a thought first at all.

January 12th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (Rubin149, Rubin152 and PG0918+02), each star observed 3 times with 3 different CCD places and 3 exposure times.
Filters  Zero point  Color term 
24.296 +/- 0.030  0.055 +/- 0.015 
25.939 +/- 0.016  0.053 +/- 0.015 
26.002 +/- 0.020  0.037 +/- 0.010 
26.114 +/- 0.012  0.025 +/- 0.025 
25.282 +/- 0.025  -0.010 +/- 0.030 
These measurements are in perfect agreement with a measured reflectivity increase of 5% after mirror washing.

February 7th, 1999

March 11th, 1999

Not a photometric night ... raining !!

April 8th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 4 standard stars (Rubin149, Rubin152, PG0942-029 and PG1633+099), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.229 +/- 0.030  0.059 +/- 0.013 
25.930 +/- 0.016  0.032 +/- 0.016 
25.972 +/- 0.018  0.043 +/- 0.010 
26.076 +/- 0.016  0.011 +/- 0.015 
25.238 +/- 0.022  -0.023 +/- 0.014 

June 06th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (Mark A, PG 2213 and Tphe), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.241 +/- 0.007  +0.035 +/- 0.025 
25.952 +/- 0.004  +0.020 +/- 0.014 
25.980 +/- 0.003  +0.020 +/- 0.014 
26.079 +/- 0.003  +0.013 +/- 0.009 
25.231 +/- 0.003  +0.021 +/- 0.015 

July 28th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (PG 1657, Mark A and PG 2213), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.213 +/- 0.011  +0.026 +/- 0.018 
25.959 +/- 0.003  +0.040 +/- 0.028 
25.968 +/- 0.002  +0.023 +/- 0.016
26.061 +/- 0.007  -0.007 +/- 0.014 
25.225 +/- 0.005  -0.017 +/- 0.012 

 August 16th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (PG 1323, PG 2213 and T Phe), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
25.934 +/- 0.003  +0.049 +/- 0.035 
25.961 +/- 0.002  +0.032 +/- 0.023 
26.060 +/- 0.002  +0.022 +/- 0.016 
25.243 +/- 0.004  -0.060 +/- 0.043 

 August 17th, 1999

The data has been obtained during a partialy photometric night (1rst part). The determinations are made from 2 standard stars (PG 1530 and SA 110), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.174 +/- 0.008  +0.086 +/- 0.061 
25.940 +/- 0.002  +0.035 +/- 0.025 
25.951 +/- 0.002  +0.042 +/- 0.030 
26.053 +/- 0.002  +0.026 +/- 0.018 
25.254 +/- 0.007  -0.067 +/- 0.049 
Mirror washing beginning of September.

September 13th, 1999

The data has been obtained during a partialy photometric night, cirrus at the end. The determinations are made from 2 standard stars (), each star observed 3 times at 3 different CCD places and with 3 exposure times. A constant absorption of 0.40 can be extrpolated !
Filters  Zero point  Color term 
23.987 +/- 0.021  +0.036 +/- 0.026 
25.630 +/- 0.018  +0.040 +/- 0.028 
25.650 +/- 0.015  +0.055 +/- 0.039 
25.741 +/- 0.012  +0.012 +/- 0.013 
24.920 +/- 0.022  -0.021 +/- 0.015 

September 14th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 1 standard stars (), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
26.022 +/- 0.029  +0.005 +/- 0.020 
26.066 +/- 0.023  +0.033 +/- 0.020 
26.166 +/- 0.005  +0.010 +/- 0.020 

 September 15th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 1 standard stars (), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
25.998 +/- 0.014  +0.005 +/- 0.020 
26.045 +/- 0.012  +0.031 +/- 0.020 
26.161 +/- 0.010  +0.011 +/- 0.020 

September 16th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 3 standard stars (PG 1657, Mark A and PG 2213), each star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.243 +/- 0.008  +0.042 +/- 0.030 
26.004 +/- 0.002  +0.043 +/- 0.030 
26.020 +/- 0.002  +0.039 +/- 0.028 
26.113 +/- 0.002  +0.016 +/- 0.011 
25.289 +/- 0.003  -0.012 +/- 0.008 

September 17th, 1999

The data has been obtained during a perfectly photometric night. The determinations are made from 1 standard star (PG 2213), the star observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.249 +/- 0.005  +0.062 +/- 0.044 
25.990 +/- 0.002  +0.027 +/- 0.019
26.019 +/- 0.003  +0.024 +/- 0.017 
26.121 +/- 0.002  +0.023 +/- 0.016 
25.287 +/- 0.003  +0.014 +/- 0.010 

November 1st, 1999

The data has been obtained during a "almost" perfectly photometric night (some clouds near the horizon). NOTE that at the beginning of the previous night it snow in La Silla (~5cm). The determinations are made from 3 standard stars (MARK_A, PG 2213, TPHE), each stars observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.231 +/- 0.007  +0.042 +/- 0.030 
25.973 +/- 0.003  +0.020 +/- 0.014 
25.991 +/- 0.002  +0.017 +/- 0.012 
26.088 +/- 0.002  +0.001 +/- 0.003 
25.248 +/- 0.004  -0.029 +/- 0.021 

December 3rd, 1999

The data has been obtained during a perfectly photometric night (very good seeing ~0.6-0.7"). The determinations are made from 3 standard stars (TPHE, PG0231, RUBIN_149), each stars observed 3 times at 3 different CCD places and with 3 exposure times.
Filters  Zero point  Color term 
24.218 +/- 0.007  +0.070 +/- 0.049 
25.961 +/- 0.002  +0.040 +/- 0.028 
25.991 +/- 0.002  +0.033 +/- 0.023 
26.095 +/- 0.001  +0.022 +/- 0.016 
25.249 +/- 0.005  -0.046 +/- 0.032 

January 2nd, 2000

A photometric night. Data obtained from (Landolt) standard star fields TPHE and RU152 (3 sets of observations, each with 3 exposures in every band).
Filters  Zero point  Color term 
23.959 +/- 0.010  0.055 +/- 0.012 
25.905 +/- 0.006  0.046 +/- 0.010 
25.962 +/- 0.003  0.030 +/- 0.004 
26.023 +/- 0.005  0.030 +/- 0.016 
25.256 +/- 0.005  -0.033 +/- 0.014 

February 29th, 2000

A photometric night. Data obtained from (Landolt) standard star fields RU152 and PG1323 (4 sets of observations, each with 3 exposures in every band)
Filters  Zero point  Color term 
23.864 +/- 0.010  0.087 +/- 0.018 
25.839 +/- 0.004  0.053 +/- 0.008 
25.890 +/- 0.005  0.059 +/- 0.020 
25.989 +/- 0.008  0.050 +/- 0.030 
25.182 +/- 0.013  0.028 +/- 0.052 

March 23-28th, 2000

Aluminization of the 3.60m telescope M1 mirror

March 29-30th, 2000
The data has been obtained during 2 photometric night (good seeing ~1.0") ... No clouds apparent, but it seems that the haze observed was producing some absorption (0.050 between the 2 nights at least). The determinations are made from 3 standard stars (PG1047,PG1323 and PG1525), one observed 4 times, each stars observed 3 times at 3 different CCD places and with 3 exposure times.

Filters  Zero point  Color term 
29/03/2000 (1 observations) 
26.013 +/- 0.003  +0.028 +/- 0.019 
26.036 +/- 0.004  +0.015 +/- 0.011 
26.113 +/- 0.002  +0.008 +/- 0.006 
25.244 +/- 0.002  -0.035 +/- 0.024 
30/03/2000 (5 observations) 
24.207 +/- 0.002  +0.072 +/- 0.051 
25.968 +/- 0.002  +0.026 +/- 0.018 
25.978 +/- 0.002  +0.025 +/- 0.018 
26.053 +/- 0.002  +0.025 +/- 0.017 
25.210 +/- 0.005  -0.031 +/- 0.022 

June 26-27th, 2000

Problem of response found ... CCD40 was dismounted and again UV floaded

June 29th, 2000
A photometric night (clouds during the 2 first hours ... After a snow storm). Data obtained from (Landolt) standard star fields PG2213, PG2336 (2 times) and Tphe (each with 3 exposures in every band)

Filters  Zero point  Color term 
24.256 +/- 0.004  +0.051 +/- 0.036 
26.005 +/- 0.003  +0.025 +/- 0.018 
26.028 +/- 0.003  +0.021 +/- 0.015 
26.109 +/- 0.004  +0.028 +/- 0.019 
i 25.263 +/- 0.007  -0.023 +/- 0.016 
July 20th, 2001
Setup night. The weather turned unphotometric after or during the observations. The range of airmass observed was small, thus the extinction term has large errors. Many stars in the R and I images were saturated, contributing to the errors. There was a bug with the headers- so no airmass or siderial time info available, and had to be calculated from the UT, so the airmass may not be very accurate. Nevertheless, these values agree well with previous values. The Landolt standard star fields PG1525 and SA110 were observed.

Note: The extinction term has been fitted as a free parameter too.
 

Filters  Zero point  Extinction Color term 
U #640 23.736 +/- 0.213 0.112 +/- 0.172 +0.047 +/- 0.013
B #639 25.858 +/- 0.409 0.150 +/- 0.310 +0.045 +/- 0.029
V #641 26.247 +/- 0.436 0.278 +/- 0.328 +0.040 +/- 0.041
R #642 26.167 +/- 0.140 0.097 +/- 0.105 +0.027 +/- 0.021
i #705 25.234 +/- 0.996 -0.008 +/- 0.730 +0.036 +/- 0.087
Jan 11th, 2001
Setup night. The sky was a little hazy and humidity was high. The Landolt standard star fields Rubin149 (centered on C), PG1047 (centred on A) and PG1323 (centred on A) were observed. Because the zeropoints are all about 0.3 mag lower than the usual values, the night is not photometric.
Note: The extinction term has been fitted as a free parameter too.
 
Filters  Zero point  Extinction Color term 
U #640 23.663 +/- 0.068 0.424 +/- 0.048  0.050 +/- 0.021 
B #639  25.573 +/- 0.046   0.174 +/- 0.030 0.024 +/- 0.019
V #641  25.668 +/- 0.061  0.088 +/- 0.039  0.002 +/- 0.025
R #642  25.711 +/- 0.042   0.024 +/- 0.028   -0.016 +/- 0.032
i #705  24.902 +/- 0.044  0.002 +/- 0.031  -0.021 +/- 0.019
Feb 12th, 2001
Setup night. The sky is clear throughout the night, and likely photometric. The Landolt standard star fields Rubin149 (centered on C), PG1047 (centred on A) and PG1323 (centred on A) were observed.

Note: The extinction term has been fitted as a free parameter too.
 

Filters  Zero point  Extinction Color term 
U #640 23.947 +/- 0.053 0.478 +/- 0.036 +0.065 +/- 0.018
B #639 25.942 +/- 0.018 0.268 +/- 0.012 +0.054 +/- 0.007
V #641 26.020 +/- 0.022 0.174 +/- 0.014 +0.024 +/- 0.008
R #642 26.075 +/- 0.010 0.114 +/- 0.006 +0.002 +/- 0.007
i #705 25.217 +/- 0.030 0.054 +/- 0.019 -0.021 +/- 0.011

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Last modified: Sat Feb 16 19:39:17 CLST 2002

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