https://github.com/lancelet/star-stream

Starfield renderer
https://github.com/lancelet/star-stream

astronomy gaia gaiadr2 rendering star

Last synced: 4 months ago
JSON representation

Starfield renderer

• Host: GitHub
• URL: https://github.com/lancelet/star-stream
• Owner: lancelet
• Created: 2019-05-18T12:38:57.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2019-06-26T11:31:54.000Z (almost 7 years ago)
• Last Synced: 2025-04-10T13:41:41.482Z (about 1 year ago)
• Topics: astronomy, gaia, gaiadr2, rendering, star
• Language: Haskell
• Size: 13.7 MB
• Stars: 11
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

Awesome Lists containing this project

README

          
===========

star-stream

===========

.. image:: https://circleci.com/gh/lancelet/star-stream.svg?style=svg

    :target: https://circleci.com/gh/lancelet/star-stream

A starfield renderer for the Gaia_ DR2 catalog.

.. code-block:: bash

  git clone --recurse-submodules git@github.com:lancelet/star-stream.git

  cd star-stream

  cabal new-build

  ghcid --command='cabal new-repl'

Results from the Gaia DR2 Star Catalog

--------------------------------------

The image below shows an equirectangular, galactic-coordinate

projection of all 1.69 billon sources in the Gaia_ DR2 catalog. This

"integrated flux" image was created by reading each of the Gaia source

catalog files (compressed CSVs) and adding the contribution of flux

from each source to each pixel it influences. The pixel influences are

calculated by multiplying the measured flux in each of the three Gaia

channels by a convolution filter (Mitchell-Netravali) centred on each

pixel.

The amount of data to be processed (~588 GB compressed) is too big to

fit in memory on the machines running this job (typically a MacBook

Pro or an iMac), so it is streamed in smaller batches, currently

corresponding to the original source CSV files. The project name

(`star-stream`) comes from this necessity to stream the data and

accumulate the image.

The output from the flux integration process is a floating-point HDR

image, which is tweaked (manually, for now) with a non-linear exposure

in an image editor.

.. image:: gaia-equirectangular-galactic.jpg

   :scale: 15 %

This is only an initial exploration. Improvements planned for

the future include:

- Add a galactic coordinate Mollweide projection

- Adjust filtering ellipse according to the local anisotropy

  of the projection

- Bucket the source observations into an acceleration structure

  for faster rendering of subsets

- Render temporal offsets for sources with proper motion

- Correlation of sources with a catalog that contains popular

  names of stars

- Etc.

Downloading the Gaia GDR2 Star Catalog

--------------------------------------

This project uses the Gaia star catalog as a data source. Gaia_ is a

space observatory launched by the European Space Agency (ESA) in 2013.

The second data release from Gaia, called GDR2, was made public on 25

April 2018. It consists of GZipped CSV files, stored on an ESA server,

comprising a total of ~588 GB of compressed data.

The gaia-fetch_ package contains a utility to download these

files. Please note that the download may be a long process. (It took 3

weeks in Sydney, Australia!)

.. _Gaia: https://en.wikipedia.org/wiki/Gaia_(spacecraft)

.. _gaia-fetch: gaia-fetch