MDI flat fields

The flatfields available through this repository are secondary flat fields for use with level 1.5/1.8 MDI high resolution continuum data. They are calculated from the method in Potts and Diver (2008, in press).

Date: The centre date of the frames used to make the flat field, and corresponding series number.
Frames: The number of frames used.
Data rejected The proportion of data rejected due to sunspots and excessive magnetic field.
y range: The rows on the CCD that the flat field covers.
Flatfield: Preview of the flatfield. Click to see a full-size image.
Flatfield error: An estimate of the error on the flatfield as a percentage of the mean flatfield value. The value is estimated by making two independent flat fields, each from half of the frames, and looking at the discrepancy between them. Where the original data contained large active regions the errors will be larger, as much data would be rejected from the flat field calculation. Click for error distribution and full-size image
Download: Click to download the fits file of the flatfield. This contains various solarsoft and MDI keywords to allow it to be loaded using fits2map in solarsoft.

The flat field changes are in general fairly gradual, but there are a few relatively large step changes, for example after June 1998, when MDI was lost. Some of these only affect the small scale structure, others change the large scale intensity variation. These steps are indicated by red and green bars across the data table. When choosing a flat field it is best to choose one that is in the same time block as your data.

For detailed instructions on the use of these flatfields please see Potts and Diver (2009, in press).

If there are any problems, or requests for additional data (eg. I can supply hot pixels lists, links to original fits files, etc) please contact me at hugh@astro.gla.ac.uk.

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1996-08-08 (031581)	2252	1.1% 15.4%	740 : 100			0.16% 0.70%	900ms focus 1
1996-12-11 (034581)	3199	1.1% 8.3%	500 : 0			0.13% 0.61%	900ms focus 1
1996-12-06 (034462)	535	0.8% 15.9%	500 : 0			0.31% 1.48%	900ms focus 1
1996-12-12 (034604)	2664	1.1% 9.8%	500 : 0			0.14% 0.64%	900ms focus 1
1997-01-17 (035470)	2733	2.8% 26.5%	613 : 113			0.14% 0.66%	900ms focus 1
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1997-01-29 (035736)	798	1.6% 42.5%	500 : 0			0.26% 1.39%	900ms focus 1
1997-03-17 (036881)	1007	0.7% 13.5%	560 : 60			0.22% 1.05%	900ms focus 1
1997-03-18 (036890)	1989	0.8% 12.1%	560 : 60			0.33% 0.71%	900ms focus 1
1997-03-21 (036977)	982	1.0% 24.4%	560 : 60			0.21% 0.95%	900ms focus 1
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1997-03-29 (037171)	2319	0.9% 8.6%	700 : 200			0.14% 0.72%	900ms focus 1
1997-08-01 (040152)	1610	1.6% 28.7%	1020 : 170			0.16% 0.85%	900ms focus 1
1997-10-18 (042041)	850	1.9% 64.9%	850 : 0			0.21% 1.05%	900ms focus 1
1997-10-17 (042019)	260	2.2% 32.3%	850 : 0			0.31% 1.73%	900ms focus 1
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1997-10-18 (042043)	590	1.7% 92.2%	850 : 0			0.27% 2.23%	900ms focus 1
1997-11-27 (043005)	3589	1.1% 5.5%	500 : 0			0.13% 0.65%	900ms focus 2
1997-12-04 (043168)	4096	6.8% 26.5%	1020 : 520			0.12% 0.61%	900ms focus 2
1998-01-08 (044013)	668	0.6% 26.2%	1020 : 170			0.27% 1.28%	900ms focus 2
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1998-04-15 (046340)	7422	2.1% 27.3%	1020 : 520			0.09% 0.48%	900ms focus 2
1998-04-22 (046510)	3169	1.0% 5.9%	850 : 0			0.12% 0.68%	900ms focus 2
1998-06-15 (047791)	6375	0.6% 4.1%	640 : 0			0.09% 0.51%	900ms focus 2
STEP CHANGE at SMALL SCALES
STEP CHANGE at LARGE SCALES
1998-10-31 (051102)	1154	7.0% 67.1%	960 : 460			0.23% 1.17%	900ms focus 2
1998-11-22 (051641)	795	1.4% 17.5%	1020 : 170			0.20% 0.95%	900ms focus 2
1998-11-26 (051738)	1475	0.7% 8.4%	500 : 0			0.19% 0.83%	900ms focus 2
1998-12-03 (051908)	7409	16.7% 44.6%	1020 : 520			0.10% 0.57%	900ms focus 2
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
1999-03-02 (054024)	660	1.7% 34.1%	935 : 85			0.27% 1.37%	900ms focus 3
STEP CHANGE at SMALL SCALES
1999-06-27 (056853)	4556	22.6% 54.5%	1020 : 520			0.14% 0.69%	900ms focus 3
1999-10-30 (059832)	2818	12.6% 62.3%	635 : 135			0.17% 0.82%	900ms focus 3
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2000-01-30 (062051)	1314	3.6% 32.8%	1000 : 150			0.19% 0.87%	900ms focus 3
2000-02-01 (062089)	604	7.6% 75.7%	930 : 80			0.29% 1.68%	900ms focus 3
2000-02-26 (062689)	554	5.7% 100.0%	850 : 0			0.32% >11.54%	900ms focus 3
2000-09-03 (067249)	2435	14.9% 50.6%	650 : 150			0.18% 0.97%	900ms focus 3
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2001-01-12 (070412)	1399	18.7% 83.3%	970 : 470			0.23% 1.32%	900ms focus 3
EXPOSURE CHANGE
2001-06-10 (073970)	3104	12.4% 72.9%	1020 : 520			0.15% 0.73%	990ms focus 3
2001-07-01 (074486)	2271	2.1% 50.3%	740 : 100			0.16% 0.84%	990ms focus 3
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2001-11-18 (077834)	945	13.5% 79.3%	840 : 340			0.28% 1.88%	990ms focus 3
2002-07-16 (083596)	1595	19.7% 94.0%	1020 : 520			0.21% 1.65%	990ms focus 4
2002-09-30 (085427)	3246	11.1% 52.3%	690 : 190			0.15% 0.77%	990ms focus 4
2002-12-27 (087545)	2990	7.3% 62.3%	1000 : 500			0.13% 0.61%	990ms focus 4
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2003-05-31 (091265)	1169	1.9% 27.7%	725 : 225			0.21% 0.94%	990ms focus 4
2003-08-03 (092787)	1988	9.8% 60.7%	880 : 380			0.17% 0.82%	990ms focus 4
2004-03-06 (097978)	1258	3.9% 32.3%	700 : 200			0.21% 1.06%	990ms focus 4
2004-06-03 (100106)	12215	2.7% 10.4%	500 : 0			0.07% 1.54%	990ms focus 4
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
EXPOSURE CHANGE
2004-10-25 (103574)	3239	8.8% 64.0%	700 : 200			0.12% 0.82%	1080ms focus 5
2004-10-30 (103686)	4574	4.5% 29.9%	505 : 5			0.10% 0.80%	1080ms focus 5
2005-05-01 (108075)	2164	15.5% 62.9%	500 : 0			0.16% 0.97%	1080ms focus 5
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2005-05-08 (108250)	1594	13.1% 80.2%	505 : 5			0.20% 2.69%	1080ms focus 5
2005-09-03 (111076)	847	3.8% 56.2%	1000 : 500			0.20% 0.93%	1080ms focus 5
2005-09-24 (111598)	1907	4.7% 52.8%	560 : 60			0.15% 0.91%	1080ms focus 5
2005-12-04 (113302)	2024	8.7% 62.3%	500 : 0			0.19% 1.52%	1080ms focus 4
STEP CHANGE at SMALL SCALES
EXPOSURE CHANGE
2006-07-03 (118345)	1141	4.5% 66.4%	561 : 61			0.23% 1.21%	1170ms focus 4
2006-07-04 (118371)	1246	9.5% 66.5%	808 : 308			0.23% 2.30%	1170ms focus 4
2006-07-13 (118596)	9617	1.2% 10.9%	561 : 61			0.09% 0.89%	1170ms focus 4
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2006-07-18 (118726)	1592	4.3% 46.1%	806 : 306			0.19% 9.54%	1170ms focus 4
STEP CHANGE at SMALL SCALES
2006-09-23 (120329)	2977	1.6% 13.9%	500 : 0			0.14% 0.70%	1170ms focus 4
2007-04-04 (124962)	957	0.8% 30.7%	561 : 61			0.20% 1.14%	1170ms focus 5
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2007-04-19 (125306)	1832	0.9% 11.3%	561 : 61			0.15% 0.70%	1170ms focus 5
2007-06-16 (126700)	7800	1.5% 6.6%	561 : 61			0.08% 0.87%	1170ms focus 4
EXPOSURE CHANGE
2008-06-25 (135697)	2997	0.7% 12.5%	505 : 5			0.12% 2.33%	1260ms focus 5
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus
2008-09-24 (137889)	3564	0.7% 9.0%	561 : 61			0.13% 5.26%	1260ms focus 4
2008-10-04 (138141)	2805	0.6% 65.0%	1000 : 500			0.13% 1.45%	1260ms focus 4
2008-10-16 (138428)	3509	1.1% 63.3%	1000 : 500			0.12% 2.61%	1260ms focus 4
2009-04-22 (142942)	5338	0.5% 6.6%	561 : 61			0.09% 2.21%	1260ms focus 5
Date (series number)	Frames	Data rejected mean % max %	y range	Flatfield	Flatfield error (%)	Flatfield error mean % max %	Other params: exposure (ms) focus

Revision history

01/07/2009: Out of beta status. Some cosmetic changes
20/04/2009: Added detailed error plots - click on the error image to see
27/01/2009: Fixed the 180 degree rotation error on the fits files
19/01/2009: Added focus and exposure data
08/01/2009: Added step change indicators
01/12/2008: Added percent errors column
29/11/2008: Made edge 3 (invalid) columns of fits files match source data
24/11/2008: Added "data rejected" column
21/11/2008: Flatfield scaling in fits files corrected