Binary data file details

As of v1.0, bsrender data files have a fixed-length 256-bit ascii header (including the file identifier in the first 11 bytes), 
followed by a variable number of 33-byte star records. The ascii header can be viewed with 'head -1 <filename>'.

Each star record includes a 64-bit unsigned integer for Gaia DR3 'source_id', three 40-bit truncaed doubles for x,y,z,
a 24-bit truncated float for linear_1pc_intensity, a 24-bit truncated float for linear_1pc_intensity_undimmed,
a 16-bit unsigned int for color_temperature, and a 16-bit unsigned int for color_temperature_unreddened.
these are packed into a 33 byte star record with each field encoded in the selected byte order.

+---------------+---------+---------+---------+-----+-----+---+---+
|   source_id   |    x    |    y    |    z    | li  |li-u | c |c-u|
+---------------+---------+---------+---------+-----+-----+---+---+
|      8        |    5    |    5    |    5    |  3  |  3  | 2 | 2 |
                              bytes

mkgalaxy and mkexternal have options to generate either little-endian or big-endian files but the bye-order of the file
must match the architecture it is used on with bsrender. This is to avoid unnessary operations in the performance
critical inner-loop of processStars() which iterates over potentially billions of star records. The filenames contain '-le'
or '-be' to indicate byte order. Byte order is also indicated with the file identifier in the first 11 bytes of the header:
BSRENDER_LE for little-endian and BSRENDER_BE for big-endian.

Output from mkgalaxy

mkgalaxy version 1.0-dev-14
Star temperatures determined by r/G and bp/G ratios when available
Star distance derived from DR3 'parallax' only
Lindegrenn et. al. parallax calibration disabled
Maximum distance of 5.0e+04 parsecs will be enforced
Output data files will be in little-endian format

Input records: 1811713157

Output by parallax quality
  pq000: 702435883
  pq001: 284451214
  pq002: 157970346
  pq003: 128186394
  pq005: 93831732
  pq010: 49465403
  pq020: 17788913
  pq030: 14670748
  pq050: 10572594
  pq100: 5837823
  Total: 1465211050

Discards
  2-parameter solution (no parallax): 341043382
  5 or 6-parameter solution but no G-band flux: 5458725
  Negative parallax: (maximum distance override enabled)

Values derived from Gaia DR3 GSPPhot fields
  Distance: (disabled)
  Undimmed intensity: 470742690
  Unreddened temperature: 470751686

Distance override (max=5.0e+04 parsecs)
  Negative parallax: 356468139
  Distance too high: 17497788

Apparent temperature derived from
  bp/rp: 1347121044
  bp/G: 453520
  rp/G: 2792969
  nu_eff_used_in_astrometry: 230686
  pseudocolor: 114612831

Temperature min/max override
  Apparent temperature < 500K: 283364
  Apparent temperature > 32767K: 89180
  Unreddened temperature < 500K: 0
  Unreddened temperature > 32767K: 13998

Incremental time: 4.298s, total time: 9660.686s

###
This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.