Magnetic_observations.html

Appended magnetic observations:

At the Debrecen Observatory there are no magnetic observations. However, we can complete the white-light observations
with magnetic observations by courtesy of several observatories (see Acknowledgements) .
If any of these magnetograms are used in publications, the original source of files should be referred to.
For further information and more data see the original sites of the observatories.

The origins of the magnetic observations are indicated in the file names:
*KittPeak*: full-disk magnetic observations copied from the archive of NSO Kitt Peak Observatory (Z UNIX compressed fits files),
*HMI*: SDO/HMI research group at Stanford University (fits files)
*MDI*: SOHO/MDI research group at Stanford University (fits files)
*GONG*: Global Oscillation Network Group (GONG) (fits files),
*MWIL*: Mount Wilson Observatory (*MWIL* fits magnetograms , *MWIL_drawing* sunspot polarity drawings),
*KANZ*: Kanzelhoehe Observatory ( Na-D filtergrams),
*HSOS*: Huairou Solar Observing Station (region observations),
*NAOJ*: Solar Observatory of NAOJ (full-disk and region observations)
*SolnDann*: scanned sunspot polarity drawings (jpg images) from the Solnechnie Dannie solar data reports edited in the Pulkovo Observatory
*IMIS*: scanned sunspot polarity drawings of Institute of terrestrial magnetism and radiowave propagation of Siberian division of RAS (Irkutsk) (SibIZMIR), and
*KrAO*: scanned sunspot polarity drawings of Crimean Astrophysical Observatory, and
*UrAO*: scanned sunspot polarity drawings of Astronomical Observatory of Ural State University, and
*UsAO*: scanned sunspot polarity drawings of Ussurijsk Astrophysical Observatory copied from Combined database of sunspot magnetic fields at Pulkovo Observatory
*YNAO*: scanned sunspot polarity drawings of Yunnan Astronomical Observatory published in Publications of Yunnan Observatory
*Rome*: Astronomical Observatory of Rome (region polarity drawings scanned from Solar Phenomena Monthly Bulletin),
*Mees*: vector magnetograms of Mees Solar Observatory, University of Hawaii, with Haleakala Stokes Polarimeter (HSP) or Imaging Vector Magnetograph (IVM)

It is important to note that magnetic measurements of sunspot umbras made at Kitt Peak are underestimates of true field strengths by a factor of about 50%. That is, one should multiply the fields by a factor of about 1.5 in umbras (Jack Harvey, 2004, personal communication).

To put a GONG fits image into "standard" orientation one first needs to rotate the image counter clock-wise by OFFSET (http://gong.nso.edu/data/DMAC_documentation/Vmbical/GONG_Image_Orientation.html).
This places Solar North at the top. Then one needs to flip the image right-for-left, thus placing Solar East on the left and Solar West on the right. If one does not have the camera offset angle one can assume on offset of 90 degrees.

Red and blue in the full-disk magnetic maps of NAOJ indicate positive (N-polarity) and negative (S-polarity) magnetic fields, respectively.
In the active region vector magnetograms red and blue contours indicate positive (N-polarity) and negative (S-polarity) magnetic fields along the line of sight, and green arrows indicate the strength and direction of transverse magnetic fields. The image orientation is celestial north at the top and west to the right.

Information copied from the site of Mees Solar observatory:
HSP Magnetograms :
Each magnetogram is a 60 kbyte GIF image. Celestial north is at the top; east is at the left.
Continuum brightness: The underlying image shows a continuum image of the region observed.
Line-of-sight component of the magnetic field: The red and blue contours show the component of the vector magnetic field projected onto the line-of-sight. Red contours indicate field towards the observer, and blue contours indicate field away from the observer.
Transverse component of the magnetic field: The short, green (or white) line segments show the direction and magnitude of the projection of the magnetic field vector into the plane perpendicular to the line of sight.
Solar Coordinates: The yellow contours show the solar coordinates of the observed region (solar latitude and central meridian distance) in degrees. Negative values indicate the eastern and southern hemispheres.
The Imaging Vector Magnetograph (IVM) at Mees Solar Observatory on Haleakala, Maui, Hawaii measures the polarization of an absorption line in the solar spectrum, and uses the polarization data to map the vector magnetic field in the solar photosphere. The IVM observes a region about 203,000 km square on the sun.