Marietta College Department of Physics Colloquium (11/16/12)

1. Crowdsourcing
the Solar System
Citizen Science with the Hubble Space
Telescope
Alex Viana, STScI
Marietta College, 11/16/12

2. Intro

3. I work for (my former
the boss)
Hubble.

4. Our Problem
There are ~10,000 archival solar system
images observed with HST's WFPC2.
Their current science products are not
optimized for moving targets.
We don't have a good catalog of what's in
these images.

5. Our Project
Create the high-quality science images
optimized for moving targets from every
WFPC2 solar system image.
Create a catalog of every object in every
WFPC2 solar system image.

6. Our Team
Max Mutchler (STScI) - P.I.
Dr. Susana Deusta (STScI)
Dr. Alberto Conti (STScI)
Alex Viana (STScI)
Dr. Mike Wong (Berkeley/University of
Michigan)
Dr. Pamela Gay (CosmoQuest, SIUE)
+ CosmoQuest Team

7. Background

8. I work here

9. STScI:

10. What Does STScI Do?
Hubble Space Telescope James Webb Space Telescope

11. The Hubble Space
Telescope
● Launched in 1990
● ~90 min orbit
● ~550 km
● Serviced 5 times
● Cameras:
○ WFC3
○ STIS
○ COS
○ ACS
○ NICMOS
○ FGS

12. Wide-Field Planetary
Camera 2
In service from 1993 -
2009.
Observed 120 nm -
1100 nm wavelengths.
Now at National Air
and Space Museum.

13. WFPC2 Images

14. Hubble’s
Wide Field 2 WFPC2:
(WF2) both the camera and it’s
Planetary Camera archival images are
kinda weird
(PC1)
Archival mosaics
are drizzled to WF pixel
scale -- which means PC
pixels are binned by 2X
No rejection of cosmic
Wide Field 3 rays or detector artifacts
(WF3) Wide Field 4 -- or worse, bad
rejections!
(WF4)
Also -- what is on the WF
chips? How many of the
WF chips have never
been inspected by
anyone?
*

15. Creating Better
Images
Blood from a Stone

16. Drizzling

17. Cosmic Ray Rejection

18. But solar system objects are "moving targets"
They have moons, which can look like cosmic
rays

19. *

20. *

21. Our science-ready images are mosaics which are clean, resampled, distortion-free,
and include cataloged secondary objects and features, with planetary parameters
embedded in their headers
*

22. Our science-ready images are mosaics which are clean, resampled, distortion-free,
and include cataloged secondary objects and features, with planetary parameters
embedded in their headers
*

23. Our science-ready images are mosaics which are clean, resampled, distortion-free,
and include cataloged secondary objects and features, with planetary parameters
embedded in their headers
*

24. The standard calibration pipelines are not optimized for moving targets
Single-image
cosmic ray rejection:
requires visual verification,
iteration, and masking
*

25. The standard calibration pipelines are not optimized for moving targets
Single-image
cosmic ray rejection:
requires visual verification,
iteration, and masking
*

26. Creating a
Catalog
Tagging the Solar System's Facebook ...

27. *

28. PDS Rings Node “finder chart”
*

29. In addition to providing finder charts for each observation, we’d like to actually catalog
the contents of each image -- what is actually detected (and what is the data quality)?
*

30. Bring on the
Citizen
Scientists!
I get by with a little help from my friends

31. *

32. *

33. The Software
Easier said than done ...

34. For Every Image ...
1. Run CR rejection
2. Run astrodrizzle (x2)
3. Create PNG (x2+)
4. Get and convert metadata
5. Talk to JPL Horizons via telnet
6. Convert coordinates and find delta in pixels
7. See if "pixels" fall on the image
8. Save all the relevant information to a
database
2,200 lines of pure Python

35. Everything Becomes
Complicated ...

36. Some Challenges
10k+ files --> 100k+ files
How do you know what version of your code
generated what files?
How do you know you code is working?
How do you keep track of every moon in 80k
different images?

37. Life as a
Research
Analyst
You have a bachelor of arts in math?

38. Links
Project: CosmoQuest.org
Code: github.com/acviana/MTPipeline/
Alex:
@AlexVianaPro
acviana.github.com
viana@stsci.edu

39. Acknowledgements
Thanks to the Marietta College Department of
Physics for inviting me.
Thanks Max Mutchler and Dr. Pamela Gay for
their slides.
This work is funded by STScI Hubble Cycle 18
Legacy Archival Research proposal 12142

40. Question?
Thanks so much for having me.