Mitaka and Milky Way texture map

Transcription

1 Mitaka and Milky Way texture map Tsunehiko Kato (4D2U Project, NAOJ) Four- Dimensional Digital Universe Project National Astronomical Observatory of Japan March 2nd, 2017 Data to Dome Workshop at Mitaka campus, NAOJ (Mitaka, Japan)

2 Today s Talk Mitaka and 4D2U Project Workshop / Practicum

3 About Mitaka and 4D2U Project

4 4D2U Dome Theater Simulation Movies The 4D2U Project The 4D2U Project is a project in NAOJ Aims: To visualize astronomical data (observation, theory, and simulation) Two Main Contents: Mitaka (Interactive software based on observation and theory) Movies (Based on numerical simulations) Contents have been used in the 4D2U Dome Theater at NAOJ Mitaka campus and also distributed on the Web

5 Mitaka Software Developed in 4D2U Project since 2003 Seamlessly navigating through space, from the Earth to the edges of the known Universe, using a variety of observational data and theoretical models Of course, the name Mitaka is named after Mitaka city (here) 10 7 m m m m m m Earth Solar System Stars Milky Way Galaxy Clusters of Galaxies Large Scale Structure It s free and open source software (MIT License)

6 Observational Data Mitaka uses a variety of up-to-date observational data: for example, topography of planets and moons; positional data of planets, moons, stars, and galaxies; surface images of planets and moons including that of Pluto. Distribution of Stars Distribution of Galaxies Surface of Pluto

7 Theoretical Models Mitaka also uses some theoretical models, including the Milky Way Galaxy model, gravitational lensing effect around the supermassive black hole at the Galactic Center, and globular cluster model. Milky Way Galaxy Model Gravitational Lensing Globular Cluster Model

8 Domemaster Mitaka supports Domemaster rendering for fish-eye projection in domes. Projection on a 5m air dome with Domemaster mode Domemaster

9 Multi-language Mitaka supports multi-language as listed below. Supported English Japanese French Spanish Italian Thai Indonesian Portuguese Will be supported Chinese Korean German and more... Users can also add their own languages by creating text files (UTF-8) that define strings.

10 Example: Thai language A strings definition file is a simple Key-Value file Key Strings //===== Solar System ===== SOLAR_SYSTEM: ระบบส ร ยะ SUN: ดวงอาท ตย PLNT_MERCURY: PLNT_VENUS: PLNT_EARTH: PLNT_MARS: PLNT_JUPITER: PLNT_SATURN: PLNT_URANUS: PLNT_NEPTUNE: PLNT_PLUTO:... ดาวพ ธ ดาวศ กร โลก ดาวอ งคาร ดาวพฤห สฯ ดาวเสาร ดาวย เรน ส ดาวเนปจ น ดาวพล โต Describe in Unicode Strings definition file for Thai language Thai language display These strings definition files are stored in the locale sub folder

11 Mitaka in Stereoscopic Domes Mitaka is used in some stereoscopic domes for scientific live shows for the public. 4D2U Dome Theater in NAOJ, Mitaka Campus (Mitaka, Tokyo, Japan) Kurobe Yoshida Science Museum (Kurobe, Toyama, Japan)

12 Download Mitaka is free and open source software and anyone can download it for personal use or educational use. For uses in planetariums or museums, please contact the 4D2U Project. System Requirements OS CPU RAM Graphics Card Display Resolution Hard Disk Space Windows 10/8.1/8/7/Vista/XP Pentium4 1.8 GHz or better 512 MB or more GeForce 3 or better 1024x768 pixels or more 150 MB or more Mitaka Website:

13 Virtual Reality (VR) Mitaka supports VR Head Mounted Display: Oculus Rift and HTC Vive Oculus Rift CV1 Mitaka VR demonstration with Oculus Rift Poster of Mitaka VR ( Model: Professor Kokubo) One can experience Mitaka in VR space!

14 Virtual Reality (VR) Supports HTC Vive Can walk around up to 3m x 4m area (Room Scale) Can operate with VR controllers Operation with VR controller Zooming-in: Pinch-out Zooming-out: Pinch-in You can experience this version of Mitaka in Practicum time this evening Operate Mitaka for VR with VR controllers by yourself!

15 Summary Mitaka is software for visualizing the Universe, from the Earth to the edges of the known Universe, with observational data and theoretical models Mitaka is free and open source software

16 Demonstration Next, let me show you a short demonstration

17 Workshop / Practicum

18 What to do? Here, instead of a workshop that specializes in Mitaka software, I ll carry out a more general one What to do in my workshop/practicum today is to make a Milky Way texture map from the Gaia DR1 data with Python Generated Milky Way map can be used for various purposes (Of course, it can be used in Mitaka software)

19 Gaia satellite Gaia is a space observatory of ESA for astrometry It will observe over 1 billion stars for 5 years and determine their 3-dimensional positions It is the successor to the Hipparcos satellite Gaia s first data release (DR1) was released on September last year

20 Gaia DR1 About 1 billion of stars were observed Among them, parallaxes of 2 million of stars were obtained The 2-dimensional positions on the celestial sphere and magnitude were obtained for all of the 1 billion stars. Those are sufficient for our purpose.

21 Restriction in DR1 data There are some restrictions in Gaia DR1 data: No color information There are some areas where number of observations are not enough. (In particular, around the Galactic center, they look like dark streaks) Because of the first point, we will make a monochrome Milky Way map. These points will be resolved in the DR2 which is scheduled at the end of this year

22 How to do? Since Milky Way is an appearance of an aggregation of stars in the Galaxy, in principle, a Milky Way map can be generated by summing up the intensities of light from individual stars one by one Here, we simply do this with Gaia DR1 data by generating an all-sky mean intensity map There are 200 billion stars in the Milky Way galaxy. 1 billion stars are enough to make Milky Way map?

23 Results This is the result, not photograph 1 billion stars are enough to reproduce a beautiful Milky Way map

24 Results Close-up of the Galactic center region Dark streaks Details of the Galactic center region are reproduced There are some dark streaks around here, as already mentioned

25 Outline 1. Introduction to Python and Jupyter Notebook 2. Downloading Gaia DR1 data 3. Extracting minimum necessary data 4. Generating intensity maps 5. Generating a cube map 6. Convert to a sphere map Section 1 will be finished in this workshop time The remainder will be done in the practicum time

26 1. Introduction to Python and Jupyter Notebook The first section is an introduction to basics of Python and Jupyter Notebook To proceed in the notebook, enter Python codes in code cells and run them step by step. Here, `Copy and Paste is OK because of the restricted time.

27 2. Downloading Gaia DR1 data Gaia DR1 data is available at: For gzipped CSV format, there are total of 5,231 files! Unfortunately, the ftp site would not be available currently, but fortunately, we can download them automatically using Python instead of clicking all the links to data files on the above site one by one, by hand.

28 3. Extracting necessary data Each data file contains data of about 220,000 stars. For each star, there are 57 types of data (ra, dec, parallax, etc.). For our purpose, only 3 data (Galactic longitude l, Galactic latitude b, and magnitude of star) are necessary. Therefore, we extract these minimum necessary data and save them into other files.

29 4. Generating intensity maps To make Milky Way map is to make the mean intensity map of starlight Here, we make the intensity map in the cube map configuration Star North Galactic Pole One of the planes Galactic Center Cell Cube Observing point O Stars are observed at the center of the cube O through one of the 6 planes of the cube O On each plane, intensities of light from stars are summed up on cells Mean intensity map is obtained on each plane of the cube

30 5. Generating a cube map Intensity maps Development view of the cube Cube map The obtained mean intensity maps are converted to a cube map image with Gamma correction

31 6. Convert to a sphere map Cube map Sphere map Finally, the cube map is converted to a sphere map, which can be used in Mitaka

32 Mapping Area Because of the restricted time, we cannot make the entire Milky Way map within the Practicum time. We can make it within the region shown in red below. However, one can make the entire map at a later date

33 Let s start workshop Open the Jupyter Notebook file named Introduction.ipynb First, copy it into your local folder and then open it in Jupyter Notebook If you cannot find in Jupyter Notebook home try the following: 1. Open command prompt 2. Move to your folder using cd command 3. Type jupyter notebook there