Observation Keys To Soho Daily Pictures

Soho is a cooperative European Space Agency (ESA)/NASA solar observation satellite. It's observing the Sun from an orbit which is located about the Lagrangian point L1 as it had launched by December 2, 1995, from the Kennedy Space Center aboard a Atlas IIAS rocket. It's providing professional and amateur astronomers with data, of them daily pictures. These daily Soho images, found on the SOHO website, are taken through various instruments. They may help building a comprehensive view of the Sun, starting at the photosphere, this surface by which our star is seen in the visible wavelengths of the spectrum, up to the corona. SOHO helped revolutionize our understanding of the Sun's interior and complex atmosphere. all pictures SOHO courtesy SOHO daily pictures

The photosphere is shown by the "MDI continuum" and the "MDI magnetogram" pictures. MDI stands for "Michelson Doppler Imager". The orange picture is almost like the Sun is looking naked-eye, limb-darkening excepted. The usual photosphere activity is shown (sunspots, faculae), as the magnetogram is showing areas of magnetic activity (white indicates a north polarity as black a south one). Most of such areas are linked to sunspots seen in the visible. Some are not associated with any sunspot however. Such areas are useful too to either track a sunspot which decayed or to anticipate where one sunspot might develop. The temperature at the photosphere is 6,000° K

The "Extreme ultraviolet Imaging Telescope" (EIT) is providing four color images. The EIT is imaging the Sun in the extreme ultraviolet as each image pictures one layer of the inferior strates of the corona (or, which is about the same, all the pictures are about the upper chromosphere). The picture are ranging from the lowest, to the highest level, in this order (the higher a layer, the hotter it is):

• the orange picture (EIT 304 angstroms) matches a layer with a temperature of 60,000-80,000° K, comprising singly ionized helium
• the blue picture (EIT 171 angstroms) is a layer with a temperature of 0.9-1 million ° K and with the 8 to 9-time ionized iron
• the green picture (EIT 195 angstroms) is 1.5 million ° K and matches a layer with the 11-tims ionized iron
• the yellow picture at last (EIT 284 angstroms) is for a layer with a temperature of 2.0-2.5 million ° K and the 14-time ionized iron

The "Large Angle Spectrometric Coronagraphs" (LASCOs) are coronagraphs, that is an occulting disk which creates an artificial eclipse. Such a tool, available for ground-based instruments too, is allowing to see the features which are seen during a total solar eclipse. The LASCO pictures are showing the corona with the coronal streamers, those nearly radial bands. Occasionally, a Coronal Mass Ejection (CME) can be seen being expelled from the Sun and crossing the field of both coronagraphs. The LASCO C2 (red picture) is showing the inner corona up to 5.25 million miles (8.4 million km) as the LASCO C3 (blue picture) is encompassing 30 million miles (45 million km), that is about half the orbit of Mercury. The white circle on the LASCO images is the actual size of Sun's disk as the dark pole is the is the occulter disk's pole. The LASCO C3 images are allowing too to see the background stars as, celestial mechanics permitting, both inferior (Mercury and Venus) and superior (starting at Mars) planets may be seen at their conjunctions

->SDO Renewed Solar Visions!

click to some renewed SDO visions. picture NASA/SDO and NASA/SDO/AIA

As launched in February 2010, NASA Solar Dynamics Observatory (SDO) is renewing the views of Sun. Such data are available in 3D further!
Top photographs are showing a snapshot in the extreme ultraviolet with different colors in the image representing different gas temperatures ranging from ~1 to 2 million degrees K (left, yellowish, credit NASA/SDO). Picture left, is showing the Sun in the multi-wavelength (211, 193 & 171 Angstrom) extreme ultraviolet with different colors in the image represent different gas temperatures ranging from ~1 to 2 million degrees K. (bluish, credit NASA/SDO/AIA; details also this credit). Varied Sun's images are available at the SDO site, of which animated views or stunning solar surface magnetic field views! The SDO, launched in 2010, observes the solar atmosphere and makes helioseismology measurements, continuously returning incredibly high-resolution images at a rapid pace of 135 megabits per second to help understand the causes of solar variability and its effect on Earth. It is carrying the following instruments: the Atmospheric Imaging Assembly (AIA), captures high resolution images every twelve seconds of the full disk of the Sun in 10 different visible and ultraviolet wavelengths; the EUV variability Experiment (EVE) produces spectra, that show the total intensity of any given extreme ultraviolet (EUV) wavelength of light coming off of the Sun; the Helioseismic and Magnetic Imager (HMI) provides maps of the magnetic fields at the Sun; the Extreme Ultraviolet Variability Experiment (EVE) measures the total output of extreme ultraviolet light from the Sun at any given time. The High Energy Solar Spectroscopic Imager (HESSI) mission which launched by February 2002 and renamed within months as the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) after Reuven Ramaty which had originated the project is also a solar tool as dedicated to solar flares as the 2006's Solar Terrestrial Relations Observatory (STEREO) is a twin satellites mission allowing a 3-D view of coronal mass ejections (CMEs) and exploring the Sun-Earth system, tracing the flow of energy and matter from the Sun to Earth. SOHO in conjunction with the two STEREO spacecraft as well as the Solar Dynamics Observatory now allow a 360-degree view of the Sun from its surface all the way to Earth's orbit, providing a much more robust picture of any given solar event. SDO can provide view of features on the Sun that are as small as 200 miles across!

A vector magnetogram by SDO, with blue showing where magnetic fields rise up and red where returning to the surface. picture site 'Amateur Astronomy' based upon a picture courtesy NASA

->Goddard Space Flight Center's Community Coordinated Modeling Center
The Community Coordinated Modeling Center, in NASA’s Goddard Space Flight Center in Greenbelt, Md., with four large plasma screens on the wall showing colorful basketball-sized images of the Sun in real time or images featuring data from particles as they flow from the Sun to the Earth, or a map of the Sun’s magnetic fields, constitutes the heart and soul of Space Weather Services at NASA, the team that keeps tabs on the Sun’s activities for the entire Agency. The center is working, among others, with the Air Force Weather Agency (AFWA), which incorporates NASA's information with other data into their own forecasts. In turn, AFWA regularly sends valuable information to Goddard to help test their models. Such modeling and observing functions allows the USA to have some powerful tools to predict space weather and potentially damaging solar events, as far as the Earth is concerned