See also wiki:SubSloanStatus2

In order to get some stats about solving smaller fields, I took 700x700 pixel (4.6 x 4.6 arcmin) subimages from SDSS. The full-size SDSS fields are cut to have 300 field objects, so these subfields have around 50 field objects each.

(For Toronto folks, this file is in raid3/SDSS-SUBFIELDS/subfield_r01.xy.fits)

Quick facts:

• Cut: tiny-21, about 222 million stars.
• Index: tiny-47, about 222 million quads.
• Index size: 8 GB.
• Run: 118.
• Quads: 2 to 2.8 arcminutes in diameter.
• Stars per field: about 32.
• Total number of fields: 7752.

Results:

Stage	Objs	Code Tolerance	N Index Stars Required	N Solved This Round	N Solved Total	% Solved Total
R1	0-50	0.005	20	5427	5427	70.01%
R2	0-50	0.01	20	923	6350	81.91%
R3	50-100	0.01	20	9	6359	82.03%
R4	0-100	0.01	15	272	6631	85.54%

The stars are distributed as shown below. Note that away from the milky way, USNOB is starting to run low on stars. This makes me think that trying to increase the star density isn't going to work very well, because some parts of the index are already using all available USNOB stars.

Here's some things that we might want to add:

• total number of index quads that were completely within the footprint?
• how many of those did we source detect all four objects?
• of those how many would have met our code tolerance?
• wall clock and cpu time

Although 32 stars per field is probably workable, the number of quads completely contained within each field is going to be smaller than 32, so this may be how we are hurting.

 http://trac.astrometry.net/browser/trunk/scripts/cuts/tiny-21/stars-all-small.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig1.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig2.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig3.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig4.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig5.png?format=raw

 http://trac.astrometry.net/attachment/wiki/SubSloanStatus/fig8.png?format=raw