Thursday, August 12, 2010

New HMI Images are available

We are now including the HMI Dopplergrams and intensitygrams in the Sun Now section. Intensitygrams are images of the Sun in the red part of the visible spectrum. They are similar to the MDI continuum images that the Stanford group has posted during the SOHO mission, but with higher spatial resolution so you can better see the details of active regions and faculae. Right now these images are in B&W and do not have the limb darkening removed.

Dopplergrams, like the one on the left, are the raw data of helioseismology, using waves at the surface of the Sun to look inside the Sun. The Dopplergrams are also shown in B&W. Parts of the Sun moving toward you are darker and those moving away are lighter in color. The rotation velocity of the Sun has not been removed and you can see that the left side of the images moves toward SDO and the right side away. That means the Sun is rotating! The pattern seen across the surface shows a convection cell called supergranulation. The Dopplergrams need to be viewed in a movie to show the p-modes.

Movies of the images will be available in a few days when enough images have been collected. You can also visit the HMI website at to see these images.