TY - JOUR
T1 - TRIPPy: Trailed Image Photometry in Python
AU - Fraser, Wesley
AU - Alexandersen, Mike
AU - Schwamb, Megan E.
AU - Marsset, Michaël
AU - Pike, Rosemary E.
AU - Kavelaars, J. J.
AU - Bannister, Michele T.
AU - Benecchi, Susan
AU - Delsanti, Audrey
PY - 2016/5/27
Y1 - 2016/5/27
N2 - Photometry of moving sources typically suffers from a reduced
signal-to-noise ratio (S/N) or flux measurements biased to incorrect low
values through the use of circular apertures. To address this issue, we
present the software package, TRIPPy: TRailed Image Photometry in
Python. TRIPPy introduces the pill aperture, which is the natural
extension of the circular aperture appropriate for linearly trailed
sources. The pill shape is a rectangle with two semicircular end-caps
and is described by three parameters, the trail length and angle, and
the radius. The TRIPPy software package also includes a new technique to
generate accurate model point-spread functions (PSFs) and trailed PSFs
(TSFs) from stationary background sources in sidereally tracked images.
The TSF is merely the convolution of the model PSF, which consists of a
moffat profile, and super-sampled lookup table. From the TSF, accurate
pill aperture corrections can be estimated as a function of pill radius
with an accuracy of 10 mmag for highly trailed sources. Analogous to the
use of small circular apertures and associated aperture corrections,
small radius pill apertures can be used to preserve S/Ns of low flux
sources, with appropriate aperture correction applied to provide an
accurate, unbiased flux measurement at all S/Ns.
AB - Photometry of moving sources typically suffers from a reduced
signal-to-noise ratio (S/N) or flux measurements biased to incorrect low
values through the use of circular apertures. To address this issue, we
present the software package, TRIPPy: TRailed Image Photometry in
Python. TRIPPy introduces the pill aperture, which is the natural
extension of the circular aperture appropriate for linearly trailed
sources. The pill shape is a rectangle with two semicircular end-caps
and is described by three parameters, the trail length and angle, and
the radius. The TRIPPy software package also includes a new technique to
generate accurate model point-spread functions (PSFs) and trailed PSFs
(TSFs) from stationary background sources in sidereally tracked images.
The TSF is merely the convolution of the model PSF, which consists of a
moffat profile, and super-sampled lookup table. From the TSF, accurate
pill aperture corrections can be estimated as a function of pill radius
with an accuracy of 10 mmag for highly trailed sources. Analogous to the
use of small circular apertures and associated aperture corrections,
small radius pill apertures can be used to preserve S/Ns of low flux
sources, with appropriate aperture correction applied to provide an
accurate, unbiased flux measurement at all S/Ns.
KW - methods: data analysis
KW - methods: numerical
KW - techniques: photometric
UR - https://arxiv.org/abs/1604.00031
U2 - 10.3847/0004-6256/151/6/158
DO - 10.3847/0004-6256/151/6/158
M3 - Article
SN - 0004-6256
VL - 151
JO - Astronomical Journal
JF - Astronomical Journal
IS - 6
M1 - 158
ER -