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)