align: Align One Epoch with Another

In esplint/IRACpm: Apply Distortion Correction to SPITZER IRAC Data

Description

Aligns output of calc_all_ch12 of one epoch to another with a simple median ra and dec shift. This can only correct small offset.

Usage

align(data1, data2, ra, dec, exclude, ERROR=75, SNR=30)

Arguments

data1	Output of calc_all_ch12 for the epoch to be shifted.
data2	Output of calc_all_ch12 for the epoch that is the reference.
ra	two component vector for RA boundaries. Will only shift sources within this bound
dec	two component vector for DEC boundaries. Will only shift sources within this bound
exclude	logical with length(data1[,1]). TRUE for sources that have known large motions between epochs.
ERROR	Sources with errors below this limit are also exclude from calculations of offsets. Default 75 mas.
SNR	Sources with SNR below this limit are also exclude from calculations of offsets. Default 30.

Details

Shifts with the following steps: (1) Identifies sources that are not excluded manually or with ERROR/SNR. (2) Identifies all sources that fit the RA and DEC boundaries. (3) Makes a two sigma clip for large motions (4) shifts data1 to align with data2 with independent RA and DEC shifts. Uses the internal functions correct_set, select_bright, and cut_error.

Value

Returns data1 with RA and DEC shifted.

Author(s)

Taran Esplin

Examples

data(E1,E2)
#plot((E2[,1:2]-E1[,1:2])*3600,pch=20,cex=.1,xlim=c(-0.3,0.3),
#  ylim=c(-0.3,0.3))
E2n <- align(E2,E1,c(48,55),c(21,35),rep(FALSE,length(E1[,1])),75,15)
#dev.new()
#plot((E2n[,1:2]-E2[,1:2])*3600,pch=20,cex=.1,xlim=c(-0.05,0.05),
#  ylim=c(-0.05,0.05))

esplint/IRACpm documentation built on May 16, 2019, 8:52 a.m.