X17 Fast Alert!
Yesterday, September 7, the GOES satellite detected a strongly enhanced X-ray flux. The curve went up to X17, the saturation level of the satellite! In the ranks, this is the fourth biggest since 1976 according to IPS.
Nederlandstalige versie /Version franaise posted on Sept 8, 2005

SXI, the solar X-ray imager onboard of GOES, 'saw' the flare. (For a movie, see below) It came from the eastern side of the solar disk. The source group that was probably responsible for several backsided CMEs last week, was baptized yesterday as 37 (Catania) and 0808 (NOAA). Unfortunately, LASCO and EIT, instruments that visualize the Sun and the surroundings and fly on SOHO, were not available. This makes it difficult to make any estimation about the associated CME. But, due to the position of the sunspot group, we know that it is mainly east-directed. At the moment, there is also a proton-event ongoing (link below). The flux increase was mainly initiated by the CME as the form of the curve shows. The curve increased gradually. If the protons were accelerated by the flare itself, the curve would be very steep.

The figure on the left is made of pictures taken with SXI: it shows the difference between 2 pictures so we call it a difference image. It shows what has changed with respect to the previous picture. The flare is clearly visible. Beneath, the X-ray flux curve as measured by GOES is plotted: you see that the saturation level is reached. GOES cannot take more.

GONG, a network of earth based solar observatories, show in their magnetograms a glimpse of the group and it looks certainly a promising group. See beneath for a picture.

We are still expecting more activity and stronger consequences as the group will rotate to the center of the disk. Stay tuned!!.

GOES X-ray / SXI-movie / proton-event / Magnetogram from GONG