# Presentation: 499079

## Architecture for All-Sky Browsing of Astronomical Datasets

**Architecture for All-Sky Browsing of Astronomical Datasets**

- Astronomical Data Analysis Software & Systems XIIBaltimore, MDOctober 13-16, 2002

**http://yourSky.jpl.nasa.gov**

**Joseph C. Jacob, Gary Block, and David W. Curkendall**
**Jet Propulsion Laboratory**
**California Institute of Technology**
**with a lot of helpful advice from****Caltech Astronomy (Djorgovski, Mahabal, Brunner now at U. of I.),****IPAC (Good, Berriman), CACR (Williams), SDSC (Kremenek)**

- Space Science Applications of Information Technology Program

**Notes:**
 Contact: Joseph Jacob, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Mail Stop 126-104, Pasadena, CA 91109-8099, email: Joseph.Jacob@jpl.nasa.gov

## Outline

- Virtual Observatories
- yourSky (http://yourSky.jpl.nasa.gov)
-  User Perspective
-  Behind the Scenes
-  Graphical Front-End
- Follow-on Activities

## Virtual Observatories

- Community driven.
- Community built.
- Community access.
- Emphasis on many interoperable components developed and deployed by domain experts in different areas.
- Highly distributed, including centers for:
- Archive
- Processing
- Visualization
- Exploit high performance computation and communications assets.

**Notes:**
To address this data avalanche problem, both NASA and the NSF are funding components of the NVO.
As a community effort, the NVO will necessarily be widely distributed with components for data archive, processing and visualization developed and deployed by domain experts in different areas.
Many of these components will require high performance computing, supercomputing, high bandwidth networks, and powerful visualization capabilities.
However the real challenge facing NVO architects is Community access.            

## Transparent Use of High Performance Infrastructure

**VO Portal**

- Supercomputers

- Huge Archives

- High Bandwidth Networks

**Remote Clients: Minimal Resource Requirements**

**Notes:**
To be effective, the NVO will need to provide transparent use of these high performance computing assets and be able to both take advantage of the high bandwidth connection to these assets, but also cope with very low bandwidth network connections and light weight computing resource at the client side.

## yourSky: A Custom ‘On-the fly’ Mosaic Portal

- Custom access = user specifies dataset, location, size, resolution, coordinate system, projection, data type, and image format.
- Architecture invites growth to expand options for custom image processing – multiple background removal techniques, overlap blending recipes, multiple surveys, etc.

**Notes:**
As one example of an NVO application that fits this architecture, we developed a custom on-the-fly mosaic portal.
Our overarching goal is to provide custom access to a compute intensive service that delivers science-grade image mosaics to user’s at their desktop.
In this context, custom access means that the user specifies dataset, location on the sky, ...
So, no matter where in the sky you are looking or how big of a region you need, you can get back just the data you want as a single FITS image. No more, no less. 
You no longer have to care about the native image partitioning scheme of the dataset you are studying.

## yourSky Custom Mosaic Portal http://yourSky.jpl.nasa.gov

- yourSky Custom Mosaic Portal http://yourSky.jpl.nasa.gov

**yourSky can access all of the publicly released DPOSS and 2MASS images for custom mosaic construction.**

**Notes:**
We call our custom mosaic service yourSky and the URL is shown here.
You enter your mosaic request parameters in a simple form interface shown here.
Two of the larger astronomy archives are accessible with yourSky: 2MASS and DPOSS.
Anyway, after you enter your request parameters, hit submit and sometime later you will receive an email specifying where to download your mosaic.

## yourSky: An Architecture for Desktop Access to Parallel Mosaic Codehttp://yourSky.jpl.nasa.gov

**yourSky**: An Architecture for Desktop Access to Parallel Mosaic Codehttp://yourSky.jpl.nasa.gov

## Custom Coordinate System and Projection

- Coordinate Systems:  Galactic, Ecliptic, J2000 Equatorial, B1950 Equatorial.
- WCS projections: LIN, TAN, SIN, STG, AZP, ARC, ZPN, ZEA, AIR, CYP, CAR, MER, CEA, COP, COD, COE, COO, BON, PCO, SFL, PAR, AIT, MOL, CSC, TSC, DSS, PLT.

**Notes:**
In yourSky, this coordinate mapping is done using the WCS library.
We support galactic, ecliptic, J2000 and B1950 equatorial coordinate systems and all of the standard WCS projections.

## Custom Image Format and Data Type

- Image Format:
- FITS
- JPEG
- PGM
- PNG
- TIFF
- Raw Data

- Data Type:
- 8-bit unsigned integer
- 8-bit signed integer
- 16-bit unsigned integer
- 16-bit signed integer
- 32-bit unsigned integer
- 32-bit signed integer
- Single precision floating point
- Double precision floating point

**Notes:**
yourSky can generate output images in different image formats and with different pixel data types.
Of course, FITS will be used most often, but, support is also provided for JPEG, PGM, ... and Raw Data.
The Raw Data format supports all of these pixel data types, but the other image formats support only a subset of these.

## Graphical Front-End to yourSkyWeb-Based Pan/Zoom Engine

**All-sky browsing at medium resolution.**
**Efficient Navigation:** Either click to re-center or zoom or enter Right Ascension (longitude), Declination (latitude) and a zoom level to jump to the desired view.
**Multi-Spectral Viewing:** View gray scale image or map any member dataset to red, green, or blue for a color image.
**Catalog Overlays:** Plot catalog objects overlaid on top of the image.
**Integrated with yourSky mosaic engine:**** **Click a link to submit a yourSky mosaic request for the current view.

## Graphical Front-End to yourSkyStatus

- All sky 1/8 resolution 2MASS and DPOSS mosaics completed:
- Multiple overlapping plates constructed to minimize distortion no matter where you look.
-  Plate locations determined by HTM vertices (HTM is Hierarchical Triangular Mesh, specified by A. Szalay, JHU under AISRP funding).
-  Nearly 1012 DPOSS and 2MASS pixels reprojected on 64 processor Origin 2000!
- To finish up we will build a “resolution pyramid” -- all sky coverage at successively coarser zoom levels to facilitate zoom functionality.
- Expect the graphical front-end to be accessible at _[http://yourSky.jpl.nasa.gov](http://yoursky.jpl.nasa.gov/)_ by November 15.

## Graphical Front-End to yourSkyArchitecture

- North Polar Region

- South Polar Region

**~70° N**

**~70° S**

- Equatorial Region

**Synoptic View**

- Hierarchical Triangular Mesh
- Single tangent plane at each vertex.

- Graphical Front-End to yourSky**Architecture**

## Graphical Front-End to yourSkyCatalog Overlays

- Zoom

## Graphical Front-End to yourSkySample Screen Capture

- Graphical Front-End to yourSky**Sample Screen Capture**

## Follow-on Activities

_**Montage:**_
- yourSky is the baseline code for Montage, an ESTO-CT Round 3 Grand Challenge Project (P.I.: T. Prince).
- Collaboration between CACR, IPAC and JPL.
- Montage will improve upon yourSky:
-  **Science Quality** – Flux preservation / Background matching.
** ****Performance** – Throughput
-  **Interoperability** with NVO infrastructure.
-  **Interoperability** with TeraGrid and Information Power Grid infrastructure.
- Montage has staged code improvement deliverables through January, 2005.

## Follow-on Activities (cont.)

_**Information Power Grid**_
- NASA’s computational grid infrastructure.
- Globus enabled version of yourSky.
- Launch yourSky mosaicking code on the Grid instead of on local machine.
- Dramatic improvements in the size and number of mosaic requests we can handle.
- Use power of the Grid to extend browse capability to full 1 arcsec resolution.

**Notes:**
At JPL we also have plans to deploy a globus enabled version of yourSky, which will allow us to launch the mosaicking code on the massive computing assets that are part of the Information Power Grid, NASA’s computational grid infrastructure.
We expect that this will lead to dramatic improvements in the size and number of mosaic requests that can be handled by yourSky.

## Summary

- yourSky supports large scale data access and image mosaicking on supercomputers.
- yourSky places minimal computing requirements on the users: Web browser.
- Requests to yourSky can be made using a simple form interface, or assisted by the graphical front-end (web-based pan/zoom).
- _[http://yourSky.jpl.nasa.gov](http://yoursky.jpl.nasa.gov/)_
- Questions?