2. ImageComparer A VO tool for variability searches The Team: Colin Aspin, Oliver Fraser, Nathaniel Paust, Rafael Santos

3. ImageComparer Scientific Aim: Using VO tools, perform automated image comparison to search for source variability. Example: DSS1 and DSS2. Look for stars in regions of active star formation, that have changed significantly in brightness between the two epochs. Many other applications for ImageComparer. Scientific Aim: Using VO tools, perform automated image comparison to search for source variability. Example: DSS1 and DSS2. Look for stars in regions of active star formation, that have changed significantly in brightness between the two epochs. Many other applications for ImageComparer.

4. ImageComparer

5. Design: use VO-enabled java/python to produce both a web-based interface and command line client to the tool. Oliver worked on the python code to grab images and catalogs from the web. Nathaniel worked on the source identification, photometry, and cross-matching. Rafael worked on the web UI and output page. Colin drunk coffee :) Design: use VO-enabled java/python to produce both a web-based interface and command line client to the tool. Oliver worked on the python code to grab images and catalogs from the web. Nathaniel worked on the source identification, photometry, and cross-matching. Rafael worked on the web UI and output page. Colin drunk coffee :)

6. ImageComparer Java code for Web UI:

7. ImageComparer Python code for VO web access:

8. ImageComparer Python code for VO web access:

9. ImageComparer

10. Python/pyraf code for image analysis:

11. ImageComparer

13. Future Improvements: Photometrically calibrate using web catalogs e.g. Tycho-2, UCAC, USNO-B, etc. Create VO accessible output - SQL DB? Integrate with VOEvent? Remove legacy software dependencies. Package command line software for client operation. Future Improvements: Photometrically calibrate using web catalogs e.g. Tycho-2, UCAC, USNO-B, etc. Create VO accessible output - SQL DB? Integrate with VOEvent? Remove legacy software dependencies. Package command line software for client operation.