Post on 11-Jan-2016
Testing and Fine-Tuning HANDS’ Automated Photometric Pipeline
Austin Barnes
OceanitMentor: Russell Knox
Advisors: Rita Cognion and Curt LeonardHome Institution: Harvard University
2009
Overview
• Problem: Space Situational Awareness
• Solution: Introduction to HANDS
• Automated Photometric Pipeline
– Calibration Star Correlator
• Recommendations
• Goal of Photometric Pipeline
Problem: Space Situational Awareness
• >19,000 objects larger than 10 cm known to orbit the planet at ~17,000 mph
• >300,000 objects between 1 and 10 cm
• February 2009 satellite collision Nasa Orbital Debris Program Office:
www.orbitaldebris.jsc.nasa.gov
Solution: HANDS
• Network of deployable robotic telescopes
• Capable of:– Astrometry– Photometry
High Accuracy Network Determination System
Automated Photometric Pipeline
SatelliteImage
Aperture Photometry
Reduced Satellite Image
Star FieldImage
Calibration Star
Correlator
Reduced Star Field
Image
Calibration Images
Calibration Star Correlator• 276 stars found• 35 matched by
position to stars in Landolt catalogue with known magnitudes
Image Credit: Kawailehua Kuluhiwa
Determining ToleranceM
agni
tude
Off
set:
Land
olt
– O
bser
ved
Angular Separation (arcsec): Landolt – Observed
Average Magnitude Offset
Automated Photometric Pipeline
SatelliteImage
Aperture Photometry
Reduced Satellite Image
Star FieldImage
Calibration Star
Correlator
Reduced Star Field
Image
Calculate Extinction
Coefficients
Calibration Images
Calculating Extinction CoefficientsSlope = Extinction Coefficient
Y-Intercept = Instrumental Magnitude Offset
Airmass
Mag
nitu
de O
ffse
t:
Land
olt
– O
bser
ved
Recommendations– Reject outliers based on deviation of ~0.8 mag from average– Allow ≥3 arcseconds of angular separation (up to 5)
Average Magnitude Offset
Mag
nitu
de O
ffse
t:
Land
olt
– O
bser
ved
Angular Separation (arcsec): Landolt – Observed
Calculating Extinction CoefficientsSlope = Extinction Coefficient
Y-Intercept = Instrumental Magnitude Offset
Airmass
Mag
nitu
de O
ffse
t:
Land
olt
– O
bser
ved
Calculating Extinction CoefficientsSlope = Extinction Coefficient
Y-Intercept = Instrumental Magnitude Offset
Airmass
Same Plot
Using
Outlier Rejection
Mag
nitu
de O
ffse
t:
Land
olt
– O
bser
ved
Automated Photometric Pipeline
SatelliteImage
Aperture Photometry
Reduced Satellite Image
Star FieldImage
Calibration Star
Correlator
Reduced Star Field
Image
Calculate Extinction
Coefficients
StandardizedLight Curves
and Measurementsof Tracked Objects
Calibration Images
Goal of Pipeline
• Catalogue standardized magnitudes of detected objects
• Identify and differentiate each object
• Identify when particular objects change
Time
Acknowledgments• Thank you to:
– Rita Cognion, Curt Leonard, Russell Knox, James Frith, Kawailehua Kuluhiwa, Brooke Gibson, and the rest of the Oceanit Ohana
– Dave Harrington, Mike Foley, Mark Pitts– Lisa Hunter, Nina Arnberg, Mike Nassir, Mark
Hoffman– Aunty Lani LeBron, Akamai Workforce Initiative, and
the rest of the Maui 2009 Interns
The 2009 Maui Akamai Internship Program is funded by the University of Hawaii, the Department of Business, Economic Development, and Tourism, the National Science Foundation Center for Adaptive Optics (NSF #AST - 9876783).
Questions?
Nasa Orbital Debris Program Office: www.orbitaldebris.jsc.nasa.gov
Using Extinction Coefficients
• Equation for Standardized Satellite Magnitude:Ms = Mi – k*X + C
Ms = Standardized Satellite Magnitude
Mi = Instrumental Magnitude
k = Extinction coefficient (slope of fitted line)
X = Airmass (1 directly overhead, increases towards horizon)
C = Instrumental Offset (Y-intercept of fitted line)