IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
What IRIS will see on 21-Aug-2017
Credit: IRIS, LMSAL/NASA, Bart De Pontieu
IRIS will actually see two eclipses of the Sun by the Moon on 21-Aug-2017. Both are partial eclipses, although one is almost total. Because of the orbital motion of IRIS these eclipses are quite brief, lasting about 15 minutes each, much shorter than the eclipse as observed from Earth. The first eclipse starts at 16:17 UTC and ends at 16:32 UTC, while the second eclipse occurs from 20:07-20:23 UTC. The movie shows the predicted path of the Moon (red circle) over the surface of the Sun (black). The short curved arc (black) shows the path that the center of the Moon takes between the two times printed in black. On 21-Aug-2017, IRIS will take some images and spectra during these eclipses to show how the Moon occults our field-of-view. During the times that IRIS does not see an eclipse, IRIS will also take data to support eclipse studies with Earth-based telescopes, including from an airplane. These eclipse studies from Earth take observations of the solar atmosphere because it is much more easily visible during a total solar eclipse as the Moon occults the much brighter solar disk. IRIS will be able to observe regions in the solar atmosphere that Earth-based observations can't see easily, so the IRIS data will be a very nice complement to such eclipse studies.