LASCO Data Products
NOTE: See retrieval
for the acknowledgement to be used when using these data products.
The NRL LASCO Library of IDL procedures is available through the SolarSoft
0.5 decompressed image files (FITS format) are available through the
LASCO online database
1 calibrated image files
- These can be downloaded through the LASCO online database by
selecting "level-1" as the file type. Note that this archive often stays up to 12-months behind realtime in order for us to ensure that the
data product has the very best calibrations available. If you need more recent data as a level-1 product, you can
contact us and we will do all we can to assist you.
2 calibrated image files
- For most of the mission, there is one polarizer sequence
taken each day in each telescope. These are used to generate Percent Polarized
(%P) and Polarized Brightness (PB) images. These are half-resolution (512x512)
images with the best available calibration available at the time of processing
applied. This product is produced as part of the regular (daily) data processing
stream. For access to these data, please contact the lasco webmaster.
Color - There are a few times when color sequences are taken which
can be combined to create color images. For details, please contact us.
C1 on/offline images - The Fabry-Perot interferometer on the C1
telescope allows images to be taken at very narrow bandpasses at discrete
wavelengths. Images of the corona at certain "emission lines" can be derived
by combining images taken on the line and off the line. Please
direct further questions to R. Schwenn.
- To obtain any of this data as a level-2 product, we ask that you contact us directly.
Daily Movies (1/2 resolution)
The daily movies are byte scaled image sequences in MPEG format on the
web and in MVI format at NRL.
Daily images are available from the SOHO
Intensity maps for east limb and west limb data showing the large-scale
solar corona as 27 day (1 rotation) views. They are available by rotation
as GIF and postscript files or by individual maps in FITS format. For an
explanation of these Carrington Maps, click here.
We have developed background models that are used to remove the static
K-corona, F-corona, and stray light from the images. These images have
been created by taking the minimum over a 4 week period of daily median
images. Several of the LASCO IDL library routines use background images
to enhance the level 0.5 image. The monthly minimum images are available
through the SolarSoft
. Normally, you will only need the two monthly minimum images
which bracket the date you are interested in. The correct background image
is retrieved using getbkgimg.pro in the LASCO IDL Library. A more detailed
explanation of filenames can be found here
for nominal monthly images. For selected roll periods (such as late 1998
and early 1999) there are special rolled
Coronal Mass Ejections
For all SOHO comet information, inlcuding lists of discoveries,
discoverers and how anyone can search for the SOHO comets,
see the Sungrazer pages
The LASCO cameras have recorded many "streaks" across the CCDs of varying
brightness, length and character. These are intrepreted to be dust particle(s)
or other debris passing in front of the telescope during an exposure.
Debris images: These
GIF files display two versions of the same image side-by-side. On the left
is a ratio of the image with the monthly median/k-corona model image. It
is best for looking at details of bright streaks. You will also find the
telescope, time and name of the original file printed along the bottom.
On the right is a difference of the image and the previous image. The mask
over the occulter and around the edges has been omitted. These are best
for seeing faint streaks.