Images are prepared in several formats, each with a type code.

The lastest image of each type is located in the directory http://soi.stanford.edu/data/full_farside/ as simple "gif" files.

These are:

Type	Link	Description	Sample
	Latest_Image.html	Date of most recent images	2011.01.11_00
syn	lastest.syn.gif	Synoptic chart with labels
N	lastest.N.gif	North pole view
S	lastest.S.gif	South pole view
syn_small	lastest.syn_small.gif	Synoptic chart with no labels, 2:1 ratio
syn_nolab	lastest.syn_nolab.gif	Synoptic chart with no labels, new 2.5:1 ratio
synanim	lastest.synanim.gif	Animated gif of syn_small, 2.0:1 ratio, 10 days
qual	lastest.qual.gif

The quality index is computed from the number of images available for the analysis. The present analysis uses 2048 minutes of Dopplergrams centered on the specified time. This requires six of the MDI 6-hour datasets. The analysis requires some data from all six datasets. If any of the datasets is missing no farside image will be available for that time and the quality image will be white. The number of minutes of good data is counted and the fraction of the color bar colored green is (2048 - 3*(missing images))/2048. Where missing images is the count of minutes without good data. The factor of 3 is used since in the farside analysis each missing minute affects (roughly) the minute itself, and a minute 4 hours before and 4 hours after which will be less effective since they will not have a companion minute. The missing fraction is colored red. If any of the datasets uses quicklook data amber will be used instead of green. This should usually happen for the most recent data and should be recomputed after a few days with final data.

So, the message is, the best quality will be a solid green bar.

In the original farside analysis, synoptic chart images were prepared with a 2:1 ratio of width to height. Since these were sine-latitude vs longitude plots they were conformal at 37 degrees latitude. Several observatories prepare sine-lat/longitude charts with a ratio of pi which makes them conformal (equidistance on the image is equidistance on the Sun) at the equator. These are too wide for easy use on the web and emphasize latitudes where there is little farside signal. We have adopted a ratio of 2.5 to 1 which is conformal at about 27 degrees which is closer to the latitude of active regions. With this mapping active regions near the start of the cycle will appear undistorted. We maintain the 2:1 version for convenience of some users.

RAW DATA: The binary format data is also available. The data is in several forms.

• FSI_lowres - this is the Postel projected merged far side data as fits files. File names are the date and time.
• helio_FS - this is the heliographic projected far side data as fits files. It is in a sine-lat vs longitude format with 200 N-S values in sine-latitude and 318 values in longitude spanning 4 radians or 0.723 degrees per bin. This allows high latitude values to be present when B0 not 0. These fits files are combined with the front side ones with the same format to make 500 pixels for 360 degrees.
• helio_M - this is the heliographic projected magnetid flux data in the same format as the helio_FS data above. The central longitude of the helio_M and helio_FS data are given in the IMG_LON keyword.

The source code is available at http://soi.stanford.edu/data/full_farside/farside++/