SOHO Extreme ultraviolet Imaging Telescope (EIT)

The SOHO Extreme ultraviolet Imaging Telescope

brought to you by

The EIT Consortium

End of SOHO EIT CME watch observations

At the end of 2010 July, SOHO's Extreme ultraviolet Imaging Telescope (EIT) completed fourteen and a half years of synoptic observations of the low corona. SDO AIA images at much higher resolution and time cadence are now available for all the EIT wavebands, and three other EUV wavelengths as well. The telemetry bandwidth that has been used by EIT will be used by LASCO to improve the cadence of its observations of the fastest CME's. EIT will continue to obtain a couple of "synoptic sets" of images in all four wavelengths per day to track detector behavior, and to maintain the uniform data set. This, and other changes in SOHO instrument operations, are part of the transition to the "Bogart" phase of the SOHO mission — designed to get the maximum science out of the mission at the minimum cost to NASA's shrinking Heliophysics Mission Operations and Data Analysis (MO&DA) budget.

EIT data will continue to be available via the Virtual Solar Observatory and via the older EIT Web catalog interface.

EIT User's Handbook , EIT Calibration, EIT software updates occur on December 10, 2001.

Accessing EIT data

If you want GIF images of EIT data....

You can find both

If you want EIT data for quantitative research....

The following procedure should be followed to obtain the EIT data in FITS format:

Determine which EIT data are available to support your study. An EIT team member can provide assistance throughout the whole process of obtaining data. To generate a list of available data, access the EIT WWW catalog interface or the Virtual Solar Observatory. The web catalog interface will provide a list and brief description of the data obtained over a range of dates. Keep in mind that the synoptic data and full-field images can also complement a study, so your data request needn't be restricted to a specific field of view or time cadence.
Note that using the Web interface, you can now download compressed tar files of the EIT FITS files

As a matter of courtesy, we ask that you send a preprint of any work involving EIT data to the EIT P.I., and after acceptance, a reprint to the EIT reprint library, care of Joe Gurman.

EIT shutterless program

The EIT group in the solar Physics Group at the Royal Observatory of Belgium is conducting a synoptic observing campaign using the high-cadence capability of the EIT instrument when run in shutterless readout mode. The latest running of the shutterless program results are available here.

EIT Shutterless campaign, [Run #38] 2010 January 7 Seg 1 Preliminary Results

2010 January 7th 19:00 - 22:00 UT

EIT Shutterless campaign, [Run #38] 2010 January 14 Seg 2 Preliminary Results

2010 January 14th 19:00 - 22:30 UT

For Archived Shutterless information, data, and movies; see The ROB High Cadence Pages

EIT and Eclipses

LASCO and EIT observing plan for 2001 June 21, including brief descriptions of the support requested by various eclipse expeditions
The EIT Eclipse 2001 page, with images and useful links, will contain images from the days around (and of) the eclipse.
The EIT Eclipse '99 page, with images and useful links, is now online.
The EIT Eclipse '98 page, with images and useful links, is now online.

EIT Calibration Rocket results

The NRL/CSL/IAS EIT rocket flight to help calibrate the SOHO EIT was launched and recovered successfully on Thursday, 1997 October 16. Preliminary results indicate that, aside from a small light leak in the Fe XV 284 Å channel, the flight was fully successful. Exposure times and detector performance appear to have been nominal.

Click on the thumbnail image on the left to access the NRL EIT calroc page.

EIT Fe XII Å observations of disk coronal mass ejection and Moreton wave, 1999 July 19

Movies of a flare-related wave and dimming indicative of a possible earthward-directed coronal mass ejection (CME).

GIF movie	Difference GIF movie
		1999 July 19 00:00 - 03:36 UT

EIT Fe XII Å observations of Solar Tornado, 1998 April 20

Movies of a helical field structure untwisting during a coronal mass ejection (CME).

[Subfield image of solar corona in Fe XII 195 Å]

MPEG Movie	QuickTime Movie	Time
		1998 April 20 08:11 - 11:02 UT

Maps of the temperature-sensitive ratio (Fe XII 195 Å/ Fe IX, X 171 Å)

The ratio is sensitive over the range 0.9 MK < T_e < 1.5 MK.


Ratio from 1997 December 6 07:00 - 07:12 UT images	Ratio from 1997 December 7 07:00 - 07:12 UT images	Ratio from 1997 December 8 07:00 - 07:12 UT images	Ratio from 1997 December 9 07:00 - 07:12 UT images


Ratio from 1997 December 10 13:00 - 13:12 UT images

Click on the thumbnail image for a full-resolution ratio map.

Older EIT movies

EIT movies from earlier observing sequences can be found on the new Cinema EIT page.

OBE history

A table showing when the OBE was loaded with new (or reloaded with older) software loads, and a partial listing of the new features introduced in those loads.

EIT synoptic maps

EIT synoptic maps in all four wavelengths in both GIF and FITS format are now available, courtesy of Elena Benevolenskaya at Stanford U. These include only central meridional charts.

Additional EIT synoptic charts may be found at the NRL EIT/LASCO synoptic maps site

EIT observing plan for tomorrow

The SOHO observing plan for tomorrow includes EIT subfield target coordinates and areas, image times and wavelengths, and formal observing campaigns.

EIT science topics

At its 1996 March meeting, the EIT Consortium decided to list some initial research topics as well as volunteers from the consortium to lead the initial efforts in each area. These are not meant to be exclusive or to indicate permanent rights of any sort, but it would benefit any prospective Guest Investigator (official or otherwise) to contact one of the Consortium members whose names are associated with a topic of interest to the Guest Investigator. The list can be thought of as the initial framework for the EIT Bulletin Board of proposed research.

Go to the EIT science topics list.

Current solar images from EIT

[green-hued representation
of EIT Fe XII image]

[red-orange hued
representation of He II/Si XI image]

The image on the left was obtained in the Fe XII emission line at 195 Å, while that on the right was obtained in He II 304 Å. Fe XII (eleven-times ionized Fe) is common at temperatures of 1.5 million K; He II is formed primarily at 60,000 - 80,000 K.

The times at which these images were obtained are available on the SDAC "current solar images" page.

While the pixel scale of the EIT instrument is 1024 x 1024 2.6-arc second pixels, the images to which these thumbnails are linked has been reduced to 512 x 512 to keep the file size reasonable (160 - 200 Kbyte).

Full resolution GIF representations of EIT images can be found here.

The LASCO/EIT observing program

The two-month-long EIT and LASCO interim synoptic program, which began 1996 May 14, ended July 16 with the modification of the on-board software. The interim synoptic schedule decribes the former LASCO C1, C2, C3 and EIT "time slots" in the daily plan. The current observing schedule is much more flexible and varied, and can be obtained by checking either the SOHO daily targets page or the SOHO Daily Operations Database.

What EIT is designed to do

The SOHO EIT is able to image the solar transition region and inner corona in four, selected bandpasses in the extreme ultraviolet (EUV):

Fe IX/X, 171 Å
Fe XII, 195 Å
Fe XV, 284 Å
He II, 304 Å

Using either full-disk or subfield images, the EIT can image active regions, filaments and prominences, coronal holes, coronal "bright points," polar plumes, and a variety of other solar features. The instrument was designed to be used in conjunction with other SOHO instruments, particularly the LASCO visible-light coronagraphs and the SUMER and CDS imaging spectrographs, as well as with ground-based instruments.

The instrument

[image of SOHO EIT telescope
without thermal insulation]

The EIT is a normal-incidence, multilayer telescope of novel design.

A paper describing the instrument (Delaboudinière et al. 1996, Solar Physics 162, 291) is available in dvi, PostScript, or Adobe pdf form.

The EIT First Results paper

(Moses et al. 1997, Solar Physics 175, 571) is available at EIT First Results

The Preflight Photometric Calibration of EIT

(Dere et al. 2000, Solar Physics 195, 13) is available at EIT Calibration

Response: updated daily

The mean counts per unit time in full-field EIT images in each of the four sectors are plotted from the beginning of operations. Note that 304 Å appears to show the greatest change with time, and with bakeout.

A table listing the times of our CCD bakeouts is given in: EIT CCD bakeout history

An image of the ratio of post- and pre-bakeout calibration lamp images from the 2000 February bakeout. Most of the enhancement occurs in the activity belts, where EUV-bright active regions appear on the E limb, rotate across the disk, and spend a few days on the W limb.

Image of the ratio of post- to pre-bakeout calibration lamp images from the 2004 September - October bakeout. Note the now narrower activity belts, closer to the solar equator than in 2002, and the lack of enhancement at the poles, due to the return of polar coronal holes to visible latitudes.

Plots are available for:

Sector	Plots
Fe IX/X 171 Å	Linear	Log-linear	Recent Linear
Fe XII 195 Å	Linear	Log-linear	Recent Linear
Fe XV 284 Å	Linear	Log-linear	Recent Linear
He II 304 Å	Linear	Log-linear	Recent Linear

The proton storm of 1997 November 6 - 10

Statistics on the EIT detector's response to the energetic proton event following the X9 flare of 1997 November 6 are available.

Engineering: EIT temperature plots

The most recent plots of:

Data rights policy

The EIT Consortium has released its data rights policy to clarify when and how access to EIT data will be available to non-Consortium members.

At the 1996 March meeting of the EIT Consortium, the Consortium members agreed on a data rights policy to encourage the "widest possible access to and analysis of the EIT data consonant with the rights of the team members whose dedication and expertise made the instrument a reality."

EIT science planning schedule

EIT science planners serve for four weeks (plus a few days). We have a tentative schedule for the next several months.

The EIT Operations Team at NASA Goddard Space Flight Center

Joe Gurman, NASA/GSFC, Co-I
Amanda Shields, ADNET, Ground Systems Manager
Kevin Schenk, ADNET, Lead Command Generator/Programmer

Send mail to:

Joe Gurman
Kevin Schenk

The SDAC home page

The SOHO home page

Web curator: Joseph B. Gurman
Responsible NASA official: Joseph B. Gurman, Facility Scientist, Solar Data Analysis Center

+1 301 286-4767

NASA Goddard Space Flight Center
Solar Physics Branch / Code 682
Greenbelt, MD 20771

Last revised - J.B. Gurman

	An image of the ratio of post- and pre-bakeout calibration lamp images from the 2000 February bakeout. Most of the enhancement occurs in the activity belts, where EUV-bright active regions appear on the E limb, rotate across the disk, and spend a few days on the W limb.

	Image of the ratio of post- to pre-bakeout calibration lamp images from the 2004 September - October bakeout. Note the now narrower activity belts, closer to the solar equator than in 2002, and the lack of enhancement at the poles, due to the return of polar coronal holes to visible latitudes.