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Makefile

@@ -0,0 +1,11 @@
+all : process crosscorrelate-hip
+
+process : process.c
+ gcc -o $@ $^
+
+crosscorrelate-hip : crosscorrelate-hip.c
+ gcc -O2 -I. -o $@ $^
+
+clean :
+ rm -rf *.o *~ process crosscorrelate-hip
+

README.md

@@ -1,2 +1,90 @@
-# gaia_dr2_hipparcos
-Gaia DR2 processor for interstitial use with Hipparcos for use with computer graphics.
+# Gaia DR2 processor for interstitial use with Hipparcos for use with computer graphics.
+
+The idea of this project is to provide a large subsection of the Gaia DR2 stars
+(approximately 11M stars). This is not particularly useful for astronomical
+purposes, however, for general user interface applications, it provides a very
+useful subset in a relatively easy-to-manage size.
+
+DISCLAIMER: When I say this is not particularly useful, I am begging you not to
+do science with the output of these tools. I am making a *lot* of compromises
+for the sake of performance, ease-of-use and visual appearance!
+
+DISCLAIMER: This repository management for this repo is weird. There will not
+be history applied to this repo, and instead it will always be a truncated
+repo.
+
+The actual output of this tool limits the data for the stars to what would be
+used to display them statically in the night sky. I.e. mas (milli-arc-seconds,
+1/mas = parseces), latitude, longitude, color (in *approximate* Hipparcos
+colors). NOTE: the hipparcos colors are used because there is much better
+research and algorithms on that mapping space to RGB.
+
+
+First, download the database.
+
+```wget -l 2 -r https://cdn.gea.esac.esa.int/Gaia/gdr2/gaia_source/csv/```
+
+Second, build 'process'
+
+```make```
+
+Third, process the stars. This searches for stars that match the following
+criteria `gmag < 13.5 && gmag > 0`. This weeds out a ton of useless celestial
+cruft. 
+
+```./process.sh```
+
+The output from this first phase is `processed.csv` this basically includes
+the lines from the original DR2 database as-is. We can then use this to cross-
+correlate with our Hipparcos dataset.
+
+## The hip2.dat data parsing.
+
+Included in this is a Hipparcos dataset parserser. What I originally used to
+generate a visually appealing starfield. The issue is that it only contained
+approximately 100,000 stars and a lot of the mas data was very, very bad.
+
+This however does contain the HIP star numbers, which is VERY useful when cross
+correlating to other databases and especially when correlating to the
+Stellarium constellationship database. 
+
+I have included `flat_stars.dat` in the `hipparcos` folder along with the files
+used to generate that data. The `flat_stars.dat` file contains star data in
+the following format:
+
+```
+ RECSTR( flatstartype, typedef struct __attribute__((__packed__)) { \
+ uint32_t rascention_bams; \
+ int32_t declination_bams; \
+ int16_t parallax_10uas; \
+ uint16_t magnitude_mag1000; \
+ int16_t bvcolor_mag1000; \
+ int16_t vicolor_mag1000; \
+ uint32_t hipparcos_id; \
+ } flat_star; );
+```
+
+And uses the following algorithm to convert for use in that file:
+
+```
+s.rascention_bams = ( ( tmp = atof( fields[4] ) )/6.28318530718)*4294967295;
+s.declination_bams = ( ( tmp = atof( fields[5] ) )/3.14159265359)*2147483647;
+s.parallax_10uas = ( tmp = atof( fields[6] ) ) * 100;
+s.magnitude_mag1000 = ( tmp = atof( fields[19] ) ) * 1000;
+s.bvcolor_mag1000 = ( tmp = atof( fields[23] ) ) * 1000;
+s.vicolor_mag1000 = ( tmp = atof( fields[25] ) ) * 1000;
+s.hipparcos_id = hc; // atoi( fields[0] );
+```
+
+This is particularly useful for generally displaying stars. And I have had
+very good luck with it, so I intend to match this sort of mentality for the
+rest of this project.
+
+Now that we have `flat_stars.dat` we can begin the cross-correlation process.
+
+
+
+
+
+
+