Latest images from the Interface Region Imaging Spectrograph (IRIS)

IRIS Today: click to open

IRIS mission and instrument paper is now available for download: LINK

IRIS’ callibration and test videos

See the first videos from the IRIS spacecraft. These images will give you an idea of its capabilities:

Prominence monitoring – large coarse 64-step raster
Sunspot osscilation – medium sit-and-stare
AR moss dynamics – large sit-and-stare
Flare watch at west limb – large coarse 4-step raster
AR11899 2-step raster at 1400A
Sit-n-stare North pole
Active region flare observations
Rapid dense raster of emerging flux region (AR11850)
E Limb AR Flare Observations

More videos to follow soon.

IRIS’ first image

First image from IRIS

These two images show a section of the sun as seen by NASA’s Interface Region Imaging Spectrograph, or IRIS, on the right and NASA’s SDO on the left. The IRIS image provides scientists with unprecedented detail of the lowest parts of the sun’s atmosphere, known as the interface region. (Credit: NASA/SDO/IRIS)

Here is a colour version of the same image from IRIS.

The Interface Region Imaging Spectrograph (IRIS) mission opens a window of discovery into this crucial region by tracing the flow of energy and plasma through the chromosphere and transition region into the corona using spectrometry and imaging. IRIS is designed to provide significant new information to increase our understanding of energy transport into the corona and solar wind and provide an archetype for all stellar atmospheres. The unique instrument capabilities, coupled with state of the art 3-D modeling, will fill a large gap in our knowledge of this dynamic region of the solar atmosphere. The mission will extend the scientific output of existing heliophysics spacecraft that follow the effects of energy release processes from the sun to Earth.

The spacecraft

The IRIS satellite design is derived from several previous NASA/LMSAL spacecraft. By re-using prior designs Lockheed Martin was able to reduce technical, scheduling and cost risks. Solar arrays omitted for clarity. Credit: LMSAL

IRIS is NASA’s Interface Region Imaging Spectrograph. Its primary goal is to understand how heat and energy move through the lower levels of the solar atmosphere.

IRIS is a class of spacecraft called a Small Explorer, which NASA defines as costing less than $120 million. Lockheed Martin (LM) Solar and Astrophysics Laboratory in LM’s Advanced Technology Center is the principle investigator institution and has overall responsibility for the mission, with major contributions from Lockheed Martin Civil Space, NASA Ames, Smithsonian Astrophysical Laboratory, Montana State University, Stanford University and the University of Oslo.

IRIS weighs 440 pounds. It is approximately 7 feet (2.1 meters) long and, with its solar panels extended, is a little over 12 feet (3.7 meters) across.


The IRIS telescope structure is nearly identical to the Solar Dynamic Observatory’s (SDO) Atmospheric Imaging Assembly (AIA) telescope structure except, instead of four telescopes, IRIS has only one. Credit: NASA/LMSAL

IRIS carries a single instrument: an ultraviolet telescope combined with an imaging spectrograph. The telescope’s primary mirror has a diameter of about eight inches (20 cm). While it will only be able to see about one percent of the sun at a time, it will be able to resolve that image to show features that are as small as 150 miles (240 km) on the sun. Such high resolution will serve as a microscope for larger instruments that capture images of the whole sun simultaneously. IRIS will collaborate with NASA’s Solar Dynamics Observatory (SDO), for example, to target active regions on the sun.

The images from IRIS’s telescope will record observations of material at specific temperatures, ranging from 5000 K and 65,000 K (and up to 10 million K during solar flares). This range is tailored to observe material traveling on the surface of the sun, called the photosphere, and in the lowermost layers of the atmosphere, called the chromosphere and transition region.

The instrument will capture a new image every five to ten seconds, and spectra about every one to two seconds. These unique capabilities will be coupled with state of the art 3-D numerical modeling on supercomputers. Using both together, scientists will be able to trace how solar material at different temperatures courses through the chromosphere and transition region.

Spectrograph – Imager

Diagram of spectrograph and slit-jaw imager with part of the internal structure and baffling. Credit: NASA/LMSAL

The spectrograph will observe material at temperatures from 5,000 K to 10 million K. Spectra provide information on exactly how much light is visible from any specific wavelength. This, in turn, corresponds to how much material is present at specific velocities, temperatures and densities.

Technical details

The IRIS instrument is a multi-channel imaging spectrograph with a 20 cm UV telescope. IRIS will obtain spectra along a slit (1/3 arcsec wide), and slit-jaw images. The CCD detectors will have 1/6 arcsec pixels. IRIS will have an effective spatial resolution between 0.33 and 0.4 arcsec and a maximum field of view of 120 arcsec.

The far-UV channel covers:

1332-1358 Å and 1390-1406 Å with 40 m Å resolution and an effective area of 2.8 cm2.

The near-UV channel covers:

2785-2835 Å with 80 mÅ resolution and an effective area 0.3 cm2.

Slit-jaw imaging will have four passbands:

1335 Å and 1400 Å with 40 Å bandpass each
2796 Å and 2831 Å with 4 Å bandpass each

IRIS will have a high data rate (0.7 Mbit/s on average) so that the baseline cadence is: 5s for slit-jaw images, 1s for 6 spectral windows, including rapid rastering to map solar regions.


IRIS is a NASA small explorer mission developed and operated by LMSAL with mission operations executed at NASA Ames Research center and major contributions to downlink communications funded by the Norwegian Space Center (NSC, Norway) through an ESA PRODEX contract.