Default search radius fails for some sources that were assigned custom apertures (bright stars, galaxies, TRAPPIST-1).

Problem description

The default search_targetpixelfile() radius of 0.0001 arcsec fails for these bright high proper motion stars with custom apertures:

EPIC ID	Campaign	new name	N Custom Aps
229002496	10	Bright Stars.gam Vir	1
236607658	111	Bright Stars.36 Oph	1
236607658	112	Bright Stars.36 Oph	1
246721980	13	Bright Stars.rho Tau	2
247599022	13	Bright Stars.tau Tau	1

Example

import lightkurve as lk

lk.search_targetpixelfile(229002496) #Current default: radius=0.0001 arcseconds

Yields: No data found for target "229002496".

Expected behavior

This source has a proper motion of ~600 mas/yr. A larger radius finds the source:

lk.search_targetpixelfile(229002496, radius=3) #arcseconds

Yields:

SearchResult containing 2 data products.

 target_name            productFilename                         description                    distance     
------------- ----------------------------------- --------------------------------------- ------------------
ktwo200084004 ktwo200084004-c101_lpd-targ.fits.gz Target Pixel Long Cadence (KTL) - C10-1 2.1207652756154594
ktwo200084004 ktwo200084004-c102_lpd-targ.fits.gz Target Pixel Long Cadence (KTL) - C10-2 2.1207652756154594

Note that these sources were assigned custom apertures owing to their large saturation bleed trails, so their TPF files get indexed by 200084004, rather than through the conventional EPIC ID 229002496.

Environment:

• lightkurve version 1.0.0 dev:
• source:

[barentsen]

One workaround we discussed is to have Lightkurve let the user know about nearby targets in the search error message. For example: No data found for target "229002496". Targets were found X arcseconds away; try increasing the search area using the `radius` keyword.

[barentsen]

(Also, it would be worthwhile to open astroquery and investigate the UserWarning raised. It doesn’t make sense.)