visualizing appropriate photometric apertures

[jpdeleon]

We have a lot of TFOP datasets that have very close neighboring stars. I wanted to check from which star the signal comes from by limiting the range of apertures in the pipeline. For example,

ta = TFOPAnalysis(target='toi06240.01', 
                  date=230811, 
                  tid=0, 
                  cids=[4,5,6], 
                  dataroot='./photometry', 
                  aperture_lims=(0, 2),    # small aper 
                  # aperture_lims=(3, 7),        # big aper
                 )

Here I superpose the selected apertures with the centroids to visualize if the aperture fully encapsulates the centroid spread.

import matplotlib.pyplot as pl
from matplotlib.patches import Circle
import astropy.units as u
import pandas as pd

def plot_apertures(starid, band_id=0, unit="arcsec", rlim=7, pix_scale=0.44, ax=None):

    d = ta.distances[starid]*u.arcmin.to(u.arcsec)
    apers_in_pix = ta.phs[band_id]._ds.aperture.data[:rlim]
    centroids = ta.phs[band_id]._ds.centroid[:,starid,]
    dx,dy = centroids.T*pix_scale

    if unit=="arcmin":
        dx*=u.arcsec.to(u.arcmin)
        dy*=u.arcsec.to(u.arcmin)
        d *=u.arcsec.to(u.arcmin)

    if ax is None:
        fig, ax = pl.subplots()
        ax.set_title(f'star ID={starid} (d={d:.1f} {unit} = {round(d/pix_scale)} pix)');
    ax.scatter(dx+d,dy+d)
    #get centroid median and place apertures there
    mx, my = np.median(dx+d), np.median(dy+d)
    ax.plot(mx, my,'ko', label=f"dx,dy=({mx:.1f},{my:.1f}) {unit}", ms=10, lw=5)
    ax.plot(d, d,'rx', ms=10, lw=5)
    for index,p in enumerate(apers_in_pix):
        ls = '--' if index%2 else '-'
        r = p*pix_scale
        if unit=="arcmin":
            r *= u.arcsec.to(u.arcmin)
        circle = Circle((mx, my), r, facecolor='none',
                        edgecolor='k', linewidth=3, alpha=0.5, ls=ls)
        ax.add_patch(circle)

    ax.set_xlabel(f'dx ({unit})')
    ax.set_ylabel(f'dy ({unit})')
    ax.legend()
    return ax

#plot the target and the nearest neighbor
idx = pd.Series(ta.distances).sort_values().argsort().index.tolist()
fig, ax = pl.subplots()
plot_apertures(idx[0], ax=ax, rlim=3);
plot_apertures(idx[1], ax=ax, rlim=3);

In this case, is it correct that aperture_lims=(0, 2) can be used to avoid flux contamination from the nearby star?