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
For further information and more data see the original sites of
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
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
Information copied from the site of Mees Solar observatory:
Each magnetogram is a 60 kbyte GIF image.
Celestial north is at the top; east is at the left.
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.