SOHO/MDI - Debrecen Sunspot Data (SDD)
Győri, L., Baranyi, T., Ludmány, A.

DATA POLICY: If the SDD data are
used in any publications, please refer to this paper:
Baranyi, T., Győri, L., Ludmány, A., On-line Tools for Solar Data Compiled at the Debrecen Observatory and their Extensions with the Greenwich Sunspot Data, Solar Physics, 291, 3081-3102, 2016, DOI: 10.1007/s11207-016-0930-1
If the SDD tilt angle data are used in any publications, please also refer to this paper:
Baranyi, T.: 2015, Comparison of Debrecen and Mount Wilson/Kodaikanal sunspot group tilt angles and the Joy's law, MNRAS, 447, (4): 1857-1865, doi:10.1093/mnras/stu2572

The production of data was done within the WP2(Photosphere) of SOTERIA (SOlar-TERrestrial Investigations and Archives) project (FP7/SP1-Cooperation/1, Nov 2008 - 31 Oct 2011). The aim of the related tasks was to cover the entire SOHO-era with the most detailed data of sunspots, sunspot groups and photospheric faculae derived from MDI (Michelson Doppler Imager) continuum images and magnetograms with a ~1 image/hour temporal resolution.
The MDI data are available by courtesy of the SOHO/MDI research group at Stanford University. SOHO (Solar and Heliospheric Observatory) is a mission of international cooperation between ESA and NASA.

Data and Image Products: (All ftp)  Additional tables: tilt angles of sunspot groups derived from SDD.  Additional tool: MySQL query for SDD    
Selected original Level 1.8. full-disk images
Processed enlarged full-disk
images (solar north at the top)
Sunspot and sunspot group data (see SDDformat.txt) Facular data
(see SDDformat.txt)
of sunspots
 Continuum intensity
Contrast enhanced intensity images

Full-disk catalogue of sunspots
Catalogue of sunspots and sunspot groups (txt) Images of sunspot groups with numbering of spots
Processed 16-bit negative images of sunspot groups
Full-disk catalogue of
continuum faculae (txt)
of faculae
1996I 1996M 1996fd_jpg
1996M_jpg fdSDD1996 SDD1996 1996group_jpg 1996group_fits facSDD1996 1996
1997I 1997M 1997fd_jpg 1997M_jpg fdSDD1997 SDD1997 1997group_jpg 1997group_fits facSDD1997 1997
1998 1998I 1998M 1998fd_jpg 1998M_jpg fdSDD1998 SDD1998 1998group_jpg 1998group_fits facSDD1998 1998
1999 1999I 1999M 1999fd_jpg 1999M_jpg fdSDD1999 SDD1999 1999group_jpg 1999group_fits facSDD1999 1999
2000 2000I 2000M 2000fd_jpg 2000M_jpg fdSDD2000 SDD2000 2000group_jpg 2000group_fits facSDD2000 2000
2001 2001I 2001M 2001fd_jpg 2001M_jpg fdSDD2001 SDD2001 2001group_jpg 2001group_fits facSDD2001 2001
2002 2002I 2002M 2002fd_jpg 2002M_jpg fdSDD2002 SDD2002 2002group_jpg 2002group_fits facSDD2002 2002
2003 2003I 2003M 2003fd_jpg 2003M_jpg fdSDD2003 SDD2003 2003group_jpg 2003group_fits facSDD2003 2003
2004 2004I 2004M 2004fd_jpg 2004M_jpg fdSDD2004 SDD2004 2004group_jpg 2004group_fits facSDD2004 2004
2005 2005I 2005M 2005fd_jpg 2005M_jpg fdSDD2005 SDD2005 2005group_jpg 2005group_fits facSDD2005 2005
2006 2006I 2006M 2006fd_jpg 2006M_jpg fdSDD2006 SDD2006 2006group_jpg 2006group_fits facSDD2006 2006
2007 2007I 2007M 2007fd_jpg 2007M_jpg fdSDD2007 SDD2007 2007group_jpg 2007group_fits facSDD2007 2007
2008 2008I 2008M 2008fd_jpg 2008M_jpg fdSDD2008 SDD2008 2008group_jpg 2008group_fits facSDD2008 2008
2009 2009I 2009M 2009fd_jpg 2009M_jpg fdSDD2009 SDD2009 2009group_jpg 2009group_fits facSDD2009 2009
2010 2010I 2010M 2010fd_jpg 2010M_jpg fdSDD2010 SDD2010 2010group_jpg 2010group_fits facSDD2010 2010
Quick-Look 2010 QL_2010I QL_2010M QL_2010fd_jpg QL_2010M_jpg - QL_SDD2010 QL_2010group_jpg QL_2010group_fits - -
Quick-Look 2011
QL_2011I QL_2011M QL_2011fd_jpg QL_2011M_jpg - QL_SDD2011 QL_2011group_jpg QL_2011group_fits - -



The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 218816. The EC contribution to the costs of the SDD project was 75%,  10% of the costs was supported by National Development Agency (Nemzeti Fejlesztési Ügynökség) under grant agreement BONUS_HU_08- BONUS_HU_08/2009-003, 15% was the institutional contribution. 

Format of the SOHO/MDI - Debrecen Sunspot Data (SDD) catalogue:

The same method is used as in the case of production of Debrecen Photoheliographic Data (DPD) sunspot catalogue, and the software of the DPD has been suitably modified in order to adapt to SOHO/MDI full-disk continuum (Ic) images. The SDD yields the position and area data of all observable sunspots on an about hourly basis (30 min =< t < day) of MDI observations as well as the digitized images of sunspot groups. The text files contain the sunspot data (see SDDformat.txt), and the images of the sunspot groups show the measured spots.  The full-disk facular data have the same format as full-disk sunspot data, but umbral areas are obviously not measured for faculae, and the first column of magnetic data contains the LOS magnetic field value at the brightest pixel within the facular contour in the intensity image.

We use the Full Disk Continuum images (fd_Ic_01h) from the Hourly Data Sets (from High Rate Science) Level 1.8. In this data set there are observations with different time resolution (from one/day to one/min) in different time intervals. In the latest years usually there is one Ic image per hour but not in every hours. To get a data set with a more or less regular time resolution that contains the most available images we have decided to use one image/hour time resolution. The best available Ic image is chosen within the time interval (hour - 30 min, hour + 30 min) which is the closest to the center of the time interval. If there is no Ic image in a given interval, the gap is filled with a Full Disk Continuum filtergram image (fd_I0_01h) when it is available.  The measured Ic and I0 images are also published in our FTP archive in the original form. File name convention: I_yyyymmdd_hhmmss. During the measuring process the selected full disk intensity images are enlarged (3x), filtered, corrected for limb darkening, and transformed to negative.  If the P_ANGLE of the image is  180 degree then  the  processed image is rotated  to  the  normal  position, otherwise  the  image preserves its original orientation.

The large amount of the available magnetograms allows for us to choose the magnetogram closest in time to the Ic image, and determine the magnetic field of the spots. Mean values of the line-of-sight magnetic field are computed if Ic images and magnetograms are available within 50 min. The best available magnetograms closest in time to the intensity images are chosen from the merged data sets of Full Disk Magnetograms of the Hourly Data Sets (from High Rate Science) and Daily Data Sets (from Low Rate Science & Synoptic) Level 1.8 (fd_M_01h and fd_M_96m_01d). All the magnetograms used in the catalogue and are available on-line. File name convention: M_yyyymmdd_hhmmss.

The set of images contains  the Ic images with the nearest magnetograms  selected after using  quality-filters and time sequence criteria.  If an hourly data is missing, it means that there is no Ic observation within the given time interval, or the available Ic observation is not measurable (perfect), or there are no measurable Ic images and magnetograms available with less than 50 min time difference.

The full-disk version of the SDD catalogue (fdSDD) is based on the same hourly time resolution MDI observations, but the spots are numbered by the computer program on the basis of their longitude and they is not assigned to sunspot groups. In the fdSDD catalogue all sunspots have their area, position and magnetic field values similar to SDD sunspot group catalogue. In this case the "g" raws are sums over the whole disk, which have no real physical meaning, but these raws are remained unchanged to
keep the format, and in this form they show the excess of one of the polarities of the line-of-sight magnetic field concentrated in spots.

The  previous version of SDD was produced during the ESA-PECS project entitled "SOHO/VIRGO, MDI - DPD catalogue studies" (2004-2007). The data (oldSDD1996) and images (old1996jpg) for 1996 are still available as samples for the results of this project.
The whole set of data is reprocessed during the SOTERIA project because the MDI magnetograms were recalibrated at the end of 2008.

Contact person: T. Baranyi (baranyi[at]

Related sites:

MDI home page
Solar Feature Catalogue

The Solar and Heliospheric Observatory -- SOHO