Creating a TPF and LCF¶

In this tutorial, we will learn the basics of tess_asteroids by creating a TPF and LCF for a couple of asteriods.

In [1]:

from tess_asteroids.utils import target_observability
from tess_asteroids import MovingTPF
import matplotlib.pyplot as plt
import numpy as np

from tess_asteroids.utils import target_observability from tess_asteroids import MovingTPF import matplotlib.pyplot as plt import numpy as np

Main-belt asteroid 1980 VR1¶

Let's start with main-belt asteroid 1980 VR1.

Was my target observed by TESS?¶

Firstly, we need to know if TESS observed this target and, if so, in what observing sector/camera/CCD. We can use the utils functions target_observability to find out. This might take a couple of minutes to run as it's checking all available TESS sectors.

In [2]:

target_observability("1980 VR1")

target_observability("1980 VR1")

Out[2]:

	sector	camera	ccd	dur
0	1	1	2	2.0
1	1	1	1	20.0
2	68	1	2	25.0

Looks like our target was observed by TESS in sectors 1 (camera 1, CCD 1 & 2) and 68 (camera 1, CCD 2). Great, now we can create a TPF and LCF for that data!

Creating a TPF¶

We can only create a TPF for one sector/camera/CCD at a time. Let's use sector 1, camera 1, CCD 1 as an example.

Initialising MovingTPF with from_name() will query the JPL/Horizons database for the target's ephemeris during that sector. The make_tpf() function will then retrieve the relevant pixel data, perform a background correction and define the target aperture.

In [3]:

# Initialise MovingTPF for asteroid 1980 VR1 in TESS sector 1, camera 1, CCD 1
target = MovingTPF.from_name("1980 VR1", sector=1, camera=1, ccd=1)

# Make TPF (if we wanted to save this as a .fits file, we would set save=True)
target.make_tpf()

# Initialise MovingTPF for asteroid 1980 VR1 in TESS sector 1, camera 1, CCD 1 target = MovingTPF.from_name("1980 VR1", sector=1, camera=1, ccd=1) # Make TPF (if we wanted to save this as a .fits file, we would set save=True) target.make_tpf()

Warning from TESSSpacecraft(): {message : ErfaWarning('ERFA function "dtf2d" yielded 1 of "dubious year (Note 6)"'), category : 'ErfaWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/erfa/core.py', lineno : 133, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
100%|█████████████████████████████████████████| 972/972 [00:16<00:00, 60.31it/s]

We can visualise the TPF by using the animate_tpf() function:

In [4]:

# Animate TPF (if we wanted to save this as a .gif file, we would set save=True)
target.animate_tpf()

# Animate TPF (if we wanted to save this as a .gif file, we would set save=True) target.animate_tpf()

Out[4]:

Once Loop Reflect

Understanding the contents of the TPF¶

The make_tpf() function creates an HDUList containing all of the TPF data. If we had set save=True, then this would have been written to a file.

The header of the "PRIMARY" HDU contains information about how the file was created, the observation and the target. Some of the keywords have been included for consistency with the SPOC TPFs (e.g. TICID, TEFF, LOGG, RADIUS...), but they are not relevant for an asteroid.

In [5]:

target.tpf_hdulist["PRIMARY"].header

target.tpf_hdulist["PRIMARY"].header

Out[5]:

SIMPLE  =                    T / conforms to FITS standard                      
BITPIX  =                    8 / array data type                                
NAXIS   =                    0 / number of array dimensions                     
EXTEND  =                    T                                                  
SIMDATA =                    F / file is based on simulated data                
ORIGIN  = 'STScI/MAST'         / institution responsible for creating this file 
SPOCDATE= '2021-05-11'         / original SPOC FFI creation date                
SPOCVER = 'spoc-5.0.12-20200925' / SPOC version that processed FFI data         
DATE    = '2025-06-06'         / file creation date.                            
TSTART  =   1331.0161538387586 / observation start time in BTJD of first frame  
TSTOP   =   1352.3909265609716 / observation start time in BTJD of last frame   
DATE-OBS= '2018-07-31T12:22:06.508' / TSTART as UTC calendar date               
DATE-END= '2018-08-21T21:21:46.872' / TSTOP as UTC calendar date                
CREATOR = 'tess-asteroids'     / software used to produce this file             
PROCVER = '1.2.4   '           / software version                               
FILEVER = '1.0     '           / file format version                            
TIMVERSN= 'OGIP/93-003'        / OGIP memo number for file format               
TELESCOP= 'TESS    '           / telescope                                      
INSTRUME= 'TESS Photometer'    / detector type                                  
DATA_REL=                   42 / SPOC data release version number               
OBJECT  = '1980 VR1'           / object name                                    
TICID   =  / unique tess target identifier                                      
SECTOR  =                    1 / Observing sector                               
CAMERA  =                    1 / Camera number                                  
CCD     =                    1 / CCD chip number                                
SHAPE   = '(11,11) '           / shape of TPF (row, column)                     
BG_CORR = 'linear_model'       / method used for background correction          
SL_CORR = 'all_time'           / method used for scattered light correction     
AP_TYPE = 'prf     '           / method used to create aperture                 
AP_NPIX =                 15.0 / average number of pixels in aperture           
PXTABLE =                    0 / pixel table id                                 
RADESYS = 'ICRS    '           / reference frame of celestial coordinates       
RA_OBJ  =                    0 / [deg] right ascension                          
DEC_OBJ =                    0 / [deg] declination                              
EQUINOX =               2000.0 / equinox of celestial coordinate system         
PMRA    =                  0.0 / [mas/yr] RA proper motion                      
PMDEC   =                  0.0 / [mas/yr] Dec proper motion                     
PMTOTAL =                  0.0 / [mas/yr] total proper motion                   
TESSMAG =                  0.0 / [mag] measured TESS magnitude                  
TESSMAG0=                  0.0 / [mag] TESS zero-point magnitude                
TEFF    =                  0.0 / [K] Effective temperature                      
LOGG    =                  0.0 / [cm/s2] log10 surface gravity                  
MH      =                  0.0 / [log10([M/H])] metallicity                     
RADIUS  =                  0.0 / [solar radii] stellar radius                   
TICVER  =                    0 / TICVER                                         
VMAG    =               15.707 / [mag] predicted V magnitude                    
HMAG    =                11.26 / [mag] H absolute magnitude                     
PERIHEL =                2.784 / [AU] perihelion distance                       
ORBECC  =                0.032 / orbit eccentricity                             
ORBINC  =               18.115 / [deg] orbit inclination                        
RARATE  =              -36.289 / ["/h] average RA rate                          
DECRATE =               -9.964 / ["/h] average Dec rate                         
PIXVEL  =                1.393 / [pix/h] average speed                          
CRMITEN =                    T / spacecraft cosmic ray mitigation enabled       
CRBLKSZ =                   10 / [exposures] s/c cosmic ray mitigation block siz
CRSPOC  =                    F / SPOC cosmic ray cleaning enabled               

The "PIXELS" HDU contains a table with the same columns as a SPOC TPF. Note: FLUX is the background corrected flux and QUALITY corresponds to the SPOC-assigned quality flags.

In [6]:

target.tpf_hdulist["PIXELS"].columns

target.tpf_hdulist["PIXELS"].columns

Out[6]:

ColDefs(
    name = 'TIME'; format = 'D'; unit = 'BJD - 2457000, days'; disp = 'D14.7'
    name = 'TIMECORR'; format = 'E'; unit = 'd'; disp = 'E14.7'
    name = 'CADENCENO'; format = 'I'
    name = 'RAW_CNTS'; format = '121I'; unit = 'e-/s'; disp = 'I8'; dim = '(11, 11)'
    name = 'FLUX'; format = '121E'; unit = 'e-/s'; disp = 'E14.7'; dim = '(11, 11)'
    name = 'FLUX_ERR'; format = '121E'; unit = 'e-/s'; disp = 'E14.7'; dim = '(11, 11)'
    name = 'FLUX_BKG'; format = '121E'; unit = 'e-/s'; disp = 'E14.7'; dim = '(11, 11)'
    name = 'FLUX_BKG_ERR'; format = '121E'; unit = 'e-/s'; disp = 'E14.7'; dim = '(11, 11)'
    name = 'QUALITY'; format = 'J'; disp = 'B16.16'
    name = 'POS_CORR1'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'POS_CORR2'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
)

The target aperture changes as a function of time. The "APERTURE" HDU contains the average aperture across all time. We can plot that as follows:

In [7]:

plt.imshow(target.tpf_hdulist["APERTURE"].data, origin="lower")
plt.xlabel("Column")
plt.ylabel("Row");

plt.imshow(target.tpf_hdulist["APERTURE"].data, origin="lower") plt.xlabel("Column") plt.ylabel("Row");

Finally, the "EXTRAS" HDU is a table containing columns not found in a SPOC TPF. For example:

• ORIGINAL_TIME is the original timestamp from the TESS FFI data. This timestamp is not accurate. TIME from the "PIXELS" HDU is more accurate and is the recommended value.
• CORNER1/CORNER2 are the original FFI column/row of the lower-left pixel in the TPF.
• PIXEL_QUALITY is defined by tess_asteroids to identify pixels that could have quality issues e.g. saturation
• APERTURE is the aperture as a function of time.

In [8]:

target.tpf_hdulist["EXTRAS"].columns

target.tpf_hdulist["EXTRAS"].columns

Out[8]:

ColDefs(
    name = 'ORIGINAL_TIME'; format = 'D'; unit = 'BJD - 2457000, days'; disp = 'D14.7'
    name = 'ORIGINAL_TIMECORR'; format = 'E'; unit = 'd'; disp = 'E14.7'
    name = 'RA_PRED'; format = 'E'; unit = 'deg'; disp = 'E14.7'
    name = 'DEC_PRED'; format = 'E'; unit = 'deg'; disp = 'E14.7'
    name = 'CORNER1'; format = 'I'; unit = 'pixel'
    name = 'CORNER2'; format = 'I'; unit = 'pixel'
    name = 'PIXEL_QUALITY'; format = '121I'; disp = 'B16.16'; dim = '(11, 11)'
    name = 'APERTURE'; format = '121J'; dim = '(11, 11)'
)

Creating a LCF¶

After we've made our TPF, we can extract the lightcurve using aperture photometry.

In [9]:

# Make LC (if we wanted to save this as a .fits file, we would set save=True)
target.make_lc()

# Make LC (if we wanted to save this as a .fits file, we would set save=True) target.make_lc()

Let's plot the lightcurve:

In [10]:

lc = target.lc["aperture"]

fig, ax = plt.subplots(1,1,figsize=(8,5))
ax.scatter(lc["time"], lc["flux"], color="deeppink", marker=".")
ax.set_xlabel("Time [BJD - 2457000]")
ax.set_ylabel("Flux [e-/s]")
ax.grid(ls=":")
ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");

lc = target.lc["aperture"] fig, ax = plt.subplots(1,1,figsize=(8,5)) ax.scatter(lc["time"], lc["flux"], color="deeppink", marker=".") ax.set_xlabel("Time [BJD - 2457000]") ax.set_ylabel("Flux [e-/s]") ax.grid(ls=":") ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");

We can use the quality flags from SPOC and tess_asteroids to mask cadences of lesser quality, and then we can highlight these on our lightcurve plot:

In [11]:

# Define array of bad binary digits from SPOC (as recommended in the TESS archive manual, excluding those not included in FFI data)
bad_spoc_bits = [1,3,5,6,15]
spoc_value = 0
for bit in bad_spoc_bits:
    spoc_value += 2**(bit-1)
    
# Define array of bad binary digits from tess_asteroids (any cadence with non-science or saturated pixels in aperture)
bad_bits = [2,4]
ta_value = 0
for bit in bad_bits:
    ta_value += 2**(bit-1)

# Joint quality mask
quality_mask = np.logical_and(lc["quality"] & ta_value == 0, target.quality & spoc_value == 0)

# Define array of bad binary digits from SPOC (as recommended in the TESS archive manual, excluding those not included in FFI data) bad_spoc_bits = [1,3,5,6,15] spoc_value = 0 for bit in bad_spoc_bits: spoc_value += 2**(bit-1) # Define array of bad binary digits from tess_asteroids (any cadence with non-science or saturated pixels in aperture) bad_bits = [2,4] ta_value = 0 for bit in bad_bits: ta_value += 2**(bit-1) # Joint quality mask quality_mask = np.logical_and(lc["quality"] & ta_value == 0, target.quality & spoc_value == 0)

In [12]:

fig, ax = plt.subplots(1,1,figsize=(8,5))
ax.scatter(lc["time"][quality_mask], lc["flux"][quality_mask], color="deeppink", marker=".")
ax.scatter(lc["time"][~quality_mask], lc["flux"][~quality_mask], color="black", marker="x")
ax.set_xlabel("Time [BJD - 2457000]")
ax.set_ylabel("Flux [e-/s]")
ax.grid(ls=":")
ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");

fig, ax = plt.subplots(1,1,figsize=(8,5)) ax.scatter(lc["time"][quality_mask], lc["flux"][quality_mask], color="deeppink", marker=".") ax.scatter(lc["time"][~quality_mask], lc["flux"][~quality_mask], color="black", marker="x") ax.set_xlabel("Time [BJD - 2457000]") ax.set_ylabel("Flux [e-/s]") ax.grid(ls=":") ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");

Understanding the contents of the LCF¶

The make_lc() function creates an HDUList containing all of the LC data. If we had set save=True, then this would have been written to a file.

The header of the "PRIMARY" HDU contains information about how the file was created and the target. It's very similar to the primary header from the TPF:

In [13]:

target.lc_hdulist["PRIMARY"].header

target.lc_hdulist["PRIMARY"].header

Out[13]:

SIMPLE  =                    T / conforms to FITS standard                      
BITPIX  =                    8 / array data type                                
NAXIS   =                    0 / number of array dimensions                     
EXTEND  =                    T                                                  
SIMDATA =                    F / file is based on simulated data                
ORIGIN  = 'STScI/MAST'         / institution responsible for creating this file 
SPOCDATE= '2021-05-11'         / original SPOC FFI creation date                
SPOCVER = 'spoc-5.0.12-20200925' / SPOC version that processed FFI data         
DATE    = '2025-06-06'         / file creation date.                            
TSTART  =   1331.0161538387586 / observation start time in BTJD of first frame  
TSTOP   =   1352.3909265609716 / observation start time in BTJD of last frame   
DATE-OBS= '2018-07-31T12:22:06.508' / TSTART as UTC calendar date               
DATE-END= '2018-08-21T21:21:46.872' / TSTOP as UTC calendar date                
CREATOR = 'tess-asteroids'     / software used to produce this file             
PROCVER = '1.2.4   '           / software version                               
FILEVER = '1.0     '           / file format version                            
TIMVERSN= 'OGIP/93-003'        / OGIP memo number for file format               
TELESCOP= 'TESS    '           / telescope                                      
INSTRUME= 'TESS Photometer'    / detector type                                  
DATA_REL=                   42 / SPOC data release version number               
OBJECT  = '1980 VR1'           / object name                                    
TICID   =  / unique tess target identifier                                      
SECTOR  =                    1 / Observing sector                               
CAMERA  =                    1 / Camera number                                  
CCD     =                    1 / CCD chip number                                
SHAPE   = '(11,11) '           / shape of TPF (row, column)                     
BG_CORR = 'linear_model'       / method used for background correction          
SL_CORR = 'all_time'           / method used for scattered light correction     
AP_TYPE = 'prf     '           / method used to create aperture                 
AP_NPIX =                 15.0 / average number of pixels in aperture           
BAD_BITS= '[1,3,7] '           / bits excluded during aperture photometry       
PXTABLE =                    0 / pixel table id                                 
RADESYS = 'ICRS    '           / reference frame of celestial coordinates       
RA_OBJ  =                    0 / [deg] right ascension                          
DEC_OBJ =                    0 / [deg] declination                              
EQUINOX =               2000.0 / equinox of celestial coordinate system         
PMRA    =                  0.0 / [mas/yr] RA proper motion                      
PMDEC   =                  0.0 / [mas/yr] Dec proper motion                     
PMTOTAL =                  0.0 / [mas/yr] total proper motion                   
TESSMAG =               14.884 / [mag] measured TESS magnitude                  
TESSMAG0=                20.44 / [mag] TESS zero-point magnitude                
TEFF    =                  0.0 / [K] Effective temperature                      
LOGG    =                  0.0 / [cm/s2] log10 surface gravity                  
MH      =                  0.0 / [log10([M/H])] metallicity                     
RADIUS  =                  0.0 / [solar radii] stellar radius                   
TICVER  =                    0 / TICVER                                         
VMAG    =               15.707 / [mag] predicted V magnitude                    
HMAG    =                11.26 / [mag] H absolute magnitude                     
PERIHEL =                2.784 / [AU] perihelion distance                       
ORBECC  =                0.032 / orbit eccentricity                             
ORBINC  =               18.115 / [deg] orbit inclination                        
RARATE  =              -36.289 / ["/h] average RA rate                          
DECRATE =               -9.964 / ["/h] average Dec rate                         
PIXVEL  =                1.393 / [pix/h] average speed                          
CRMITEN =                    T / spacecraft cosmic ray mitigation enabled       
CRBLKSZ =                   10 / [exposures] s/c cosmic ray mitigation block siz
CRSPOC  =                    F / SPOC cosmic ray cleaning enabled               

The "LIGHTCURVE" HDU contains all of the data. For example:

• FLUX and FLUX_ERR are created from the TPF using aperture photometry.
• MOM_CENTR1/2 are the measured flux-weighted centroids of the target.
• QUALITY is the original SPOC assigned quality flag.
• AP_QUALITY is defined by tess_asteroids to identify cadences that could have quality issues e.g. saturated pixels.

In [14]:

target.lc_hdulist["LIGHTCURVE"].columns

target.lc_hdulist["LIGHTCURVE"].columns

Out[14]:

ColDefs(
    name = 'TIME'; format = 'D'; unit = 'BJD - 2457000, days'; disp = 'D14.7'
    name = 'TIMECORR'; format = 'E'; unit = 'd'; disp = 'E14.7'
    name = 'ORIGINAL_TIME'; format = 'D'; unit = 'BJD - 2457000, days'; disp = 'D14.7'
    name = 'ORIGINAL_TIMECORR'; format = 'E'; unit = 'd'; disp = 'E14.7'
    name = 'CADENCENO'; format = 'I'
    name = 'QUALITY'; format = 'J'; disp = 'B16.16'
    name = 'FLUX'; format = 'E'; unit = 'e-/s'; disp = 'E14.7'
    name = 'FLUX_ERR'; format = 'E'; unit = 'e-/s'; disp = 'E14.7'
    name = 'TESSMAG'; format = 'E'; unit = 'mag'; disp = 'E14.7'
    name = 'TESSMAG_ERR'; format = 'E'; unit = 'mag'; disp = 'E14.7'
    name = 'FLUX_BKG'; format = 'E'; unit = 'e-/s'; disp = 'E14.7'
    name = 'FLUX_BKG_ERR'; format = 'E'; unit = 'e-/s'; disp = 'E14.7'
    name = 'MOM_CENTR1'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'MOM_CENTR1_ERR'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'MOM_CENTR2'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'MOM_CENTR2_ERR'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'RA'; format = 'E'; unit = 'deg'; disp = 'E14.7'
    name = 'DEC'; format = 'E'; unit = 'deg'; disp = 'E14.7'
    name = 'AP_QUALITY'; format = 'I'; disp = 'B16.16'
    name = 'FLUX_FRACTION'; format = 'E'; disp = 'E14.7'
    name = 'CORNER1'; format = 'I'; unit = 'pixel'
    name = 'CORNER2'; format = 'I'; unit = 'pixel'
    name = 'EPHEM1'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'EPHEM2'; format = 'E'; unit = 'pixel'; disp = 'E14.7'
    name = 'RA_PRED'; format = 'E'; unit = 'deg'; disp = 'E14.7'
    name = 'DEC_PRED'; format = 'E'; unit = 'deg'; disp = 'E14.7'
)

Near-Earth asteroid 2013 OS3¶

Let's now have a look at near-Earth asteroid 2013 OS3:

In [15]:

target_observability("2013 OS3")

target_observability("2013 OS3")

Out[15]:

	sector	camera	ccd	dur
0	20	2	1	10.0
1	20	2	2	1.0
2	20	2	3	6.0
3	20	1	2	3.0
4	20	1	3	0.0
5	93	2	3	4.0
6	93	1	2	4.0

This asteroid passed through five camera/CCD combinations during sector 20! That's because it moves much faster across the TESS detectors due to its proximity to Earth (and hence TESS). Notice that sector 20, camera 2, CCD 3 has duration of 0.0 days - this just means it was observed for less than a day on this CCD.

In [16]:

# Initialise MovingTPF for asteroid 2013 OS3 in TESS sector 20, camera 2, CCD 3
target = MovingTPF.from_name("2013 OS3", sector=20, camera=2, ccd=3)

# Make TPF
target.make_tpf()

# Animate TPF
target.animate_tpf()

# Initialise MovingTPF for asteroid 2013 OS3 in TESS sector 20, camera 2, CCD 3 target = MovingTPF.from_name("2013 OS3", sector=20, camera=2, ccd=3) # Make TPF target.make_tpf() # Animate TPF target.animate_tpf()

Some of the requested pixels are outside of the FFI science array (1<=row<=2048, 45<=col<=2092), but they will be set to NaN in your TPF.
Warning from TESSSpacecraft(): {message : ErfaWarning('ERFA function "dtf2d" yielded 1 of "dubious year (Note 6)"'), category : 'ErfaWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/erfa/core.py', lineno : 133, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).
100%|█████████████████████████████████████████| 291/291 [00:06<00:00, 47.88it/s]
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).

Out[16]:

Once Loop Reflect

Notice that this asteroid has a more elongated shape. Due to the speed with which it moves across the TESS detector, the flux gets smeared along the trail during the long exposures. In a few of the frames, the asteroid reaches the edge of the TPF, so we are probably losing some of the target's flux. That's no problem, we can create a larger TPF to ensure we capture all of the flux! (Note: The first cadence of this TPF is filled with NaN values because these are non-science pixels.)

In [17]:

# Make TPF - larger shape
target.make_tpf(shape=(15,15))

# Animate TPF
target.animate_tpf()

# Make TPF - larger shape target.make_tpf(shape=(15,15)) # Animate TPF target.animate_tpf()

Some of the requested pixels are outside of the FFI science array (1<=row<=2048, 45<=col<=2092), but they will be set to NaN in your TPF.
Warning from TESSSpacecraft(): {message : ErfaWarning('ERFA function "dtf2d" yielded 1 of "dubious year (Note 6)"'), category : 'ErfaWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/erfa/core.py', lineno : 133, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Column(s) >= 2093 '), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 56, line : None}
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).
100%|█████████████████████████████████████████| 291/291 [00:09<00:00, 29.29it/s]
Warning from prf.evaluate(): {message : LKPRFWarning('`targets` contains collateral pixels: Row(s) > 2048)'), category : 'LKPRFWarning', filename : '/Users/atuson/miniforge3/lib/python3.10/site-packages/lkprf/tessprf.py', lineno : 62, line : None}
The PRF model contained nans in the first frame (cadence number 591). The model was replaced with that from the following frame (cadence number 592).

Out[17]:

Once Loop Reflect

That looks better, the target is more comfortably within the bounds of the TPF now.

In [18]:

# Make LC
target.make_lc()

lc = target.lc["aperture"]

# Joint quality mask
quality_mask = np.logical_and(lc["quality"] & ta_value == 0, target.quality & spoc_value == 0)

fig, ax = plt.subplots(1,1,figsize=(8,5))
ax.scatter(lc["time"][quality_mask], lc["flux"][quality_mask], color="deeppink", marker=".")
ax.scatter(lc["time"][~quality_mask], lc["flux"][~quality_mask], color="black", marker="x")
ax.set_xlabel("Time [BJD - 2457000]")
ax.set_ylabel("Flux [e-/s]")
ax.grid(ls=":")
ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");

# Make LC target.make_lc() lc = target.lc["aperture"] # Joint quality mask quality_mask = np.logical_and(lc["quality"] & ta_value == 0, target.quality & spoc_value == 0) fig, ax = plt.subplots(1,1,figsize=(8,5)) ax.scatter(lc["time"][quality_mask], lc["flux"][quality_mask], color="deeppink", marker=".") ax.scatter(lc["time"][~quality_mask], lc["flux"][~quality_mask], color="black", marker="x") ax.set_xlabel("Time [BJD - 2457000]") ax.set_ylabel("Flux [e-/s]") ax.grid(ls=":") ax.set_title(f"Asteroid {target.target} in Sector {target.sector} Camera {target.camera} CCD {target.ccd}");