TESS eclipses near V345 Lac

I am searching public TESS Quick-Look Pipeline light curves around V345 Lacertae for eclipsing binaries the variable-star catalogs do not already describe. TESS pixels are 21 arcseconds wide, so a small telescope on the ground can do something TESS cannot: see which star actually fades.

Next eclipses

The next two predicted eclipses for each star that still needs a ground check, soonest first. V345 Lac is a known binary, so it is not in this schedule. After a minimum passes, that line drops off and the following one takes its place. These times come from the TESS ephemerides. The new stars have not been checked from the ground, and a middle can be off by a couple of hours.

TIC 330732812. Next eclipse: not predictable yet.

TIC 421781407. The fade is KV Cep, 60 arcsec away. No date for this star.

The TESS spacecraft before launch. Four cameras sit inside the sunshade, and the solar arrays are deployed.
TESS before launch. The four cameras are the dark hoods inside the sunshade. Side by side they watch a strip of sky 24 by 96 degrees, and one pixel is 21 arcseconds. Credit: Orbital ATK / NASA.

Where each sector looks

light curves on this page other sectors V345 Lac

Loading the sky…

Drag the globe and click a sector. Each strip is four cameras, 24 degrees each. TESS stares at one sector for about 27 days, then steps to the next. The pale sectors in the first view are the original two-year plan. The red ones are sectors 16, 17, 56, 57, 76, 77, 83, and 84, which supplied the light curves on these pages. The footprints are the public tess-point planning pointings, not a measured image header. With JavaScript off, a still of NASA’s first-year drawing is shown instead. Star positions: d3-celestial, Olaf Frohn. Still: NASA Goddard / CI Lab.

The search is a set of growing circles on stars brighter than about V = 12.5. It started inside 0.60° of V345 Lac, then 0.71°, 0.80°, 0.90°, and on out to 1.20°. The chart below draws those circles. The same tests have since been run out to 1.60°. A dip counts only when it repeats, is smooth, and sits on clean cadences. The outer rings were also checked for brightenings and for any period. The same tests recover known variables. Those are not listed here.

Seventeen stars in that field are mine to follow up. One, TIC 330739083, is filed with the AAVSO Variable Star Index (VSX) and is waiting on a moderator. Four more are saved there as drafts and are not public yet: TIC 330735422, TIC 422106434, TIC 431033666, and a revision of the existing entry for TIC 330247030. A new account can have only one new star in review, so those drafts stay drafts. Six more have notes here and are not filed. TIC 467474053, from the 1.50° ring, fades by 0.19 mag every 3.32 days, with a shallower minimum halfway between. TIC 415156807, also from that ring, fades by 0.07 mag every 8.33 days, and a brighter star 33 arcsec away fades with it, so that dip is not assigned. Four new additions come from the 1.50–1.60° ring and are not filed. TIC 422108500 fades by 0.24 mag every 6.10 days, with a shallower minimum at phase 0.74. TIC 328546841 fades by 0.12 mag every 8.38 days, with a second minimum of 0.08 mag. TIC 415460747 and TIC 2015971564, 0.75 arcsec apart, fade together by about 0.13 mag every 4.53 days, and the host is not assigned. TIC 328548852 is a candidate: 0.05 mag every 2.83 days, and the aperture is contaminated. TIC 422224891 fades by 0.08 mag every 2.99 days, and a star 38 arcsec away fades with it. TIC 430806628 fades by 0.06 mag every 1.87 days. TIC 329864959 fades by 0.03 mag every 4.52 days. The dip on TIC 421781407 is the known eclipsing binary KV Cep, 60 arcsec away. BD+54 2721 fades for about a day on a 100.8-day period and is not filed. TIC 330732812 has two eclipses and no period. V345 Lac was already catalogued. Its timing note, with the diagrams, is the last item in the list.

Wide field. V345 Lac is the center. The gold circle is 0.9°. The outer circle is 1.2°. East is left.
1.2°0.9°α Lacβ LacNGC 7243V345 LacTIC 330247030TIC 330739083TIC 330735422TIC 431033666TIC 330732812BD+54 2721TIC 422106434TIC 422224891TIC 430806628TIC 329864959TIC 421781407TIC 467474053TIC 415156807TIC 422108500TIC 328546841TIC 415460747 and TIC 2015971564TIC 328548852N up · E left · Lacerta

α Lac, β Lac, and the open cluster NGC 7243 are only there so the field has a landmark. Five finds sit inside the gold circle. BD+54 2721 is just outside it. The 1.2° circle also holds TIC 422106434 and four stars that were measured and not filed: TIC 422224891, TIC 430806628, TIC 329864959, and TIC 421781407. TIC 467474053 and TIC 415156807 sit outside that circle. They are the two stars from the 1.40–1.50° ring. Farther out, TIC 422108500, TIC 328546841, TIC 415460747, and TIC 328548852 are the new additions from the 1.50–1.60° ring. Open the close chart to tell the inner stars apart, or use the list under it.

Close chart. Rings are the search as it grew: 0.60°, 0.71°, 0.80°, 0.90°, 1.20°, and the two outer rings at 1.50° and 1.60°. Click a star.
0.60°0.71°0.80°0.90°1.20°1.50°1.60°V345 LacTIC 330247030TIC 330739083TIC 330735422TIC 431033666TIC 330732812TIC 330615780TIC 422106434TIC 422224891TIC 430806628TIC 329864959TIC 421781407TIC 467474053TIC 415156807TIC 422108500TIC 328546841TIC 415460747TIC 328548852N up · E left · 1° is 152 px

The stars

Sorted by the next predicted eclipse. The schedule at the top of the page also lists the eclipse after that. TIC 330732812 has no period yet, so it stays after the stars that have one. TIC 421781407 has no clock of its own, because the dip is KV Cep. V345 Lac is last. It is the known binary at the center of the search, and that page is a timing note on a published star. Its predicted times stay on that page. They are not in this list, and they are not in Next eclipses.

Times on these pages are predictions from TESS. The new stars have not been checked from the ground yet.

Discoveries to date

Every star this search has turned up, by where it stands. The first group is new from the 1.50–1.60° ring and is not filed. The second is filed with VSX or saved there as drafts. The third has TESS measurements and needs eyes on the ground before it can be filed.

New additions, 1.50–1.60° ring

StarVTypePeriodStatus
TIC 422108500RA 22h 22m 58.24s, Dec +56° 02′ 47.7″ (J2000) · 335.74265°, +56.04658°11.82EA candidate, eccentric, 6.10 days6.10311 dNew addition, 28 Oct 2026. Not filed. Not yet checked from the ground.
TIC 328546841RA 22h 08m 20.75s, Dec +54° 30′ 33.3″ (J2000) · 332.08644°, +54.50924°10.51EA candidate, both minima, 8.38 days8.38460 dNew addition, 28 Oct 2026. Not filed. Not yet checked from the ground.
TIC 415460747 and TIC 2015971564
TIC 415460747RA 22h 29m 07.77s, Dec +54° 56′ 08.8″ (J2000) · 337.28238°, +54.93579°		12.13One eclipse, two stars 0.75 arcsec apart, 4.53 days4.53364 dNew addition, 28 Oct 2026. Not filed. The two stars are 0.75 arcsec apart, and the host is not assigned.
TIC 328548852RA 22h 07m 52.00s, Dec +54° 53′ 03.0″ (J2000) · 331.96667°, +54.88417°11.75Candidate, 0.05 mag, 2.83 days2.82924 dNew addition, 28 Oct 2026. Candidate. The aperture is contaminated, so the host is not settled.

Filed with VSX

StarVTypePeriodStatus
TIC 330739083RA 22h 16m 29.87s, Dec +55° 10′ 16.0″ (J2000) · 334.12445°, +55.17111°11.31EA, primary only in the TESS data7.62189 d (or 7.625 d)Submitted to VSX 9 Oct 2026, in review. Not public yet.
TIC 330735422RA 22h 15m 56.93s, Dec +54° 28′ 38.7″ (J2000) · 333.98722°, +54.47741°11.78EA, shallow primary28.239 dVSX draft saved. Waits for the star in review.
TIC 422106434RA 22h 22m 51.91s, Dec +55° 36′ 49.7″ (J2000) · 335.71628°, +55.61381°9.96EA, primary and secondary, 9.53 days9.53361 dVSX draft saved 15 Oct 2026. Waits for the star in review.
TIC 431033666RA 22h 19m 04.50s, Dec +53° 48′ 36.7″ (J2000) · 334.76874°, +53.81019°11.10EA, flat-bottomed primary, 68 days68.12 dVSX draft saved 15 Oct 2026. Waits for the star in review.
TIC 330247030RA 22h 14m 23.88s, Dec +54° 29′ 26.1″ (J2000) · 333.59950°, +54.49058°11.49EA, eclipses at both conjunctions12.479 dIn VSX as a 35-minute variable. Draft revision with the 12.5-day eclipses saved 15 Oct 2026.

Needs follow-up observations

StarVTypePeriodStatus
TIC 467474053RA 22h 26m 09.59s, Dec +53° 38′ 54.3″ (J2000) · 336.53995°, +53.64841°12.06EA candidate, primary and secondary, 3.32 days3.31699 dNot filed. Not yet checked from the ground.
TIC 415156807RA 22h 28m 48.17s, Dec +54° 29′ 49.3″ (J2000) · 337.20070°, +54.49702°11.92Dip every 8.33 days, star not assigned8.33038 dNot filed. A star 33 arcsec away also fades. The source is not assigned.
TIC 422224891RA 22h 24m 03.23s, Dec +55° 25′ 23.6″ (J2000) · 336.01348°, +55.42323°12.38One minimum every 2.99 days, star not assigned2.98922 dNot filed. A star 38 arcsec away fades on the same clock.
TIC 430806628RA 22h 15m 32.62s, Dec +53° 41′ 19.4″ (J2000) · 333.88592°, +53.68871°10.32One minimum every 1.87 days1.86948 dNot filed. Not yet checked from the ground.
TIC 329864959RA 22h 12m 58.79s, Dec +53° 59′ 04.3″ (J2000) · 333.24497°, +53.98453°8.54Shallow minimum, 4.52 days4.52285 dNot filed. The dip is shallow.
TIC 330732812RA 22h 16m 07.29s, Dec +53° 56′ 04.6″ (J2000) · 334.03038°, +53.93462°11.34EA, period not fixedNot fixed yetNot ready. Two eclipses do not pick a period.
BD+54 2721
TIC 330615780RA 22h 15m 11.18s, Dec +55° 29′ 15.5″ (J2000) · 333.79659°, +55.48763°		9.54Day-long fades, 100.8 days100.85 dNot filed. Not yet checked from the ground.
Reference and ruled out. V345 Lac (TIC 421726141, RA 22h 18m 43.34s, Dec +54° 40′ 33.5″ (J2000) · 334.68057°, +54.67596°; V = 11.25, period 7.4919092 d) is the known eclipsing binary at the center of the search. Its page is a timing note, not a new star. TIC 421781407 (RA 22h 19m 02.74s, Dec +55° 50′ 05.0″ (J2000) · 334.76143°, +55.83474°; V = 12.21) is ruled out. Its dip is KV Cep, an eclipsing binary already in VSX, 60 arcsec away.

Known contaminant

ASASSN-V J222336.95+555418.1 is an EA eclipsing binary already in the catalog, V = 10.02–10.30, period 1.4949 days.

RA 22h 23m 36.95s, Dec +55° 54′ 18.1″ (J2000, from the ASAS-SN designation)

It sits 79 arcseconds from TIC 422226915 (V = 12.45), about 1.418° from V345 Lac, just past the 1.40° ring. It is about 2.4 mag brighter, and its eclipses are diluted into the TESS aperture of TIC 422226915. That produces dips of about 14 percent on a 1.495-day clock in TESS sectors 16, 17, 56, 57, 83, and 84.

The sine-wave period search missed it. The dip-timing test caught it.