White Light Full-Disk Observation

1918 - 1998: Photographic observation with 20cm Zeiss Refractor at Mitaka (specification is here)
1938 - 1998: Sunspot drawing observation with 20cm Zeiss Refractor at Mitaka (specification is here)
1998 - current: 10cm Refractor wiht a CCD camera at Mitaka

*The observations until May 1998 were test observations, and the data are incomplete and for reference only. Therefore, please do not use it for data analysis.

10cm Refractor: Full-Disk Images (jpg file, 1000x1000 pixels)

2020 2021 2022 2023 2024
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
1997 1998 1999
The image orientation is celestial north at the top and west to the right.
The files are named “srYYYYMMDD.jpg”, where ‘YYYYMMDD’ is the date of observation.

10cm Refractor: Computer-Generated Drawings (postscript file)

2020 2021 2022 2023 2024
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
1997 1998 1999
The image orientation is celestial north at the top and west to the right.
The files are named “spotYYYYMMDD1.ps”, where ‘YYYYMMDD’ is the date of observation.
Criteria of the sunspot detection and drawing:
Individual sunspots are detected based on the criterion that the brightness of two or more neighboring pixels on the CCD falls below a threshold value. Threshold values for the sunspot detection are defined as follows:
•Penumbra: mi - (6.0×sd) …(a),
•Umbra: mi - (30.0×sd) …(b),
where, “mi” and “sd” are the mean and standard deviation of brightness derived from a FITS sdYYYYMMDD.fts, respectively. All features satisfying the threshold (a) are detected as individual sunspots and drawn with contour lines. Areas satisfying the threshold (b) are filled in black as umbrae.

10cm Refractor: Sunspot (Group) Parameters

2020 2021 2022 2023 2024
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
1997 1998 1999
The files are named “spotYYYYMMDD.txt” or “spotgroupYYYYMMDD.txt” (including parameters of sunspot groups), where ‘YYYYMMDD’ is the date of observation.
•Description of Sunspot (Group) Parameters (html)
•Description of Sunspot (Group) Parameters (Text file)

10cm Refractor:Sunspot Area Data, 1998--

10cm Refractor: Full-Disk Images (FITS-format data)

2020 2021 2022 2023 2024
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
1997 1998 1999
The files are named “srYYYYMMDD.fts” or “sdYYYYMMDD.fts” (limb-darkening corrected), where ‘YYYYMMDD’ is the date of observation.