exoclock

Qatar-4b (LOW)

Discovered by: Alsubai et al. 2017

The Star
Simbad
GAIA
2MASS		 Qatar 4
DR2 385697172809355392
J00192622+4401395
RA 00:19:26.2245 DEC +44:01:39.484
Parallax
3.011 mas		 P.M. RA
0.985 mas/y		 P.M. DEC
-8.866 mas/y
MagV
13.6		 MagR
13.68		 MagI*
12.636		 MagJ
12.03		 MagH
11.631		 MagK
11.519
MagG
13.411		 MagGBP
13.892		 MagGRP
12.783
*Calculated from GAIA magnitudes.

Ephemeris - Verified True
Kokori et al. 2025
Mid-time
2459316.76367 ± 0.00011 BJDTDB
Period
1.80536404 ± 3.1e-07 days
Transit Parameters
Alsubai et al. 2017
Rp/Rs
0.138 ± 0.003		 a/Rs
7.1 +0.5 -0.5
 i
87.5 +1.6 -1.6 deg
e
-		 ω
- deg
DepthR*
25.42 mmag		 Duration*
2.14 hours
*Calculated from the other parameters, using PyLightcurve.
**Adjusted based on the space observations.

Limb Darkening Parameters
Alsubai et al. 2017
Teff
5215.0 +50.0 -50.0 K
 Log(g)
4.53 +0.06 -0.06 cm/s2
 Fe/H
0.1 +0.08 -0.08 dex
ExoClock Status
Observing Priority LOW
Minimum aperture 10.08"
Total Observations (Recent) 138 (29)
O-C 1.03 ± 0.17 minutes
ExoClock Observations (Recent) 123 (29)
Space Observations (Recent) 12 (0)
ETD Observations (Recent) 0 (0)
Literature Mid-times (Recent) 3 (0)
Kepler Rp/Rs -
TESS Rp/Rs 0.1367 ± 0.0012

Qatar-4b


ExoClock Observations
Planet
Observation Date		 Observer
Observatory		 Telescope
Camera / Filter / Exp [s]		 O-C
minutes
Qatar-4b (LOW)
2025-12-27		Matthieu Bachschmidt
Gonachon		Celestron C11
SBIG ST8XME / AstrodonExoPlanet-BB / 120.0		1.71 ± 1.07
Qatar-4b (LOW)
2025-12-27		Tommaso Dittadi
TD-TRO		Ritchey-Chretien
Moravian G2-1600 / R / 240.0		0.69 ± 0.99
Qatar-4b (LOW)
2025-12-27		Stefano Lora
MarSEC		Ritchey Chrétien
Moravian G2 Mark II / R / 150.0		-1.3 ± 2.02
Qatar-4b (LOW)
2025-12-27		Manfred Raetz
privat observatory Herges-Hallenberg		SCT 280/1850 (C11 with Starizona reducer)
Moravian Instruments G2-1600 / AstrodonExoPlanet-BB / 120.0		-3.2 ± 1.43
Qatar-4b (LOW)
2025-12-25		Michael Nezel
Celle Observatory		CDK 14
QHY 268M / I / 180.0		2.17 ± 1.09
Qatar-4b (LOW)
2025-12-07		samuel Diaz Lopez
Tomas Lopez (AstroCamp)		SCA260
ASI2600MM / rpr / 180.0		1.78 ± 1.17
Qatar-4b (LOW)
2025-11-28		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-0.32 ± 1.43
Qatar-4b (LOW)
2025-11-19		Snaevarr Guðmundsson
Ness Observatory		Meade LX 200 ACF Schmidt-Cassegrain
SBIG STL 11000M / AstrodonExoPlanet-BB / 120.0		0.17 ± 0.92
Qatar-4b (LOW)
2025-11-10		Salvador Miquel Romero
Vedat Observatory		Meade SN10 F/4.1
SBIG ST8XME / Clear / 300.0		-3.36 ± 3.31
Qatar-4b (LOW)
2025-11-09		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-1.89 ± 0.91
Qatar-4b (LOW)
2025-10-11		Pieter Vuylsteke
Marvel (La Palma)		ASA Ritchey
ZWO 6200mm / rpr / 200.0		3.55 ± 0.91
Qatar-4b (LOW)
2025-10-02		Pieter Vuylsteke
Marvel (La Palma)		ASA Ritchey
ZWO 6200mm / rpr / 200.0		3.38 ± 0.63
Qatar-4b (LOW)
2025-10-02		Lionel Rousselot
Private observatory Vierzon		Newton 250/740
ZWO 533 monochrome / Lum / 180.0		2.44 ± 0.66
Qatar-4b (LOW)
2025-10-02		Arushi Nath
Arushi Nath		12" Ritchey- Chretien Pro
ASI 2600 Mono Camera / R / 180.0		1.98 ± 1.87
Qatar-4b (LOW)
2025-09-24		Harri Kiiskinen
Hankasalmi observatory		RCOS Carbon Tube Ritchey-Chrétien Telescope
SBIG STX-16803 / R / 60.0		1.2 ± 1.87
Qatar-4b (LOW)
2025-09-24		David Molina
AnunakiObservatory		APO80
KAF8300 / Clear / 180.0		-3.7 ± 4.46
Qatar-4b (LOW)
2025-09-23		Simon Dawes
William James II		Celestron Edge11 HD
Risingcam Monochrome SONY imx571 / Lum / 300.0		-2.89 ± 1.87
Qatar-4b (LOW)
2025-09-14		Pieter Vuylsteke
Marvel (La Palma)		ASA Ritchey
ZWO 6200mm / rpr / 200.0		2.79 ± 0.66
Qatar-4b (LOW)
2025-09-05		Wilfried Hartmann
Observatory Stargate, Austria		Skywatcher 8" f/4
QHY MiniCam8 Mono / R / 91.0		1.49 ± 2.02
Qatar-4b (LOW)
2025-08-17		Gerold Holtkamp
Gerold Holtkamp		Newtonian
QHY268M / Lum / 120.0		3.13 ± 1.44
Qatar-4b (LOW)
2025-08-17		Tommaso Dittadi
TD-TRO		Ritchey-Chretien
Moravian G2-1600 / I / 240.0		1.84 ± 1.58
Qatar-4b (LOW)
2025-08-17		Lionel Rousselot
Private observatory Vierzon		Newton 250/740
ZWO 533 monochrome / Lum / 180.0		1.32 ± 0.86
Qatar-4b (LOW)
2025-08-17		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		1.1 ± 0.81
Qatar-4b (LOW)
2025-08-16		Jeff Rodriguez
Moeller Observatory		Planeware PW1000
ZWO ASI 294MMpro / V / 60.0		0.34 ± 0.56
Qatar-4b (LOW)
2025-08-08		Tommaso Dittadi
TD-TRO		Ritchey-Chretien
Moravian G2-1600 / R / 240.0		2.01 ± 1.87
Qatar-4b (LOW)
2025-08-08		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-1.16 ± 1.34
Qatar-4b (LOW)
2025-07-30		Antonino Brosio
ABObservatory		Skywatcher Newton Quattro 300P
Atik 383 L / Clear / 240.0		2.47 ± 1.87
Qatar-4b (LOW)
2025-07-30		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-1.39 ± 0.92
Qatar-4b (LOW)
2025-07-20		Arushi Nath
Arushi Nath		12" Ritchey- Chretien Pro
ASI 2600 Mono Camera / R / 180.0		0.14 ± 1.44
Qatar-4b (LOW)
2024-12-20		Deborah Smith
Complejo Astronomico Los Coloraos, Gorafe		C9.25
QHY9 / R / 210.0		1.86 ± 1.73
Qatar-4b (LOW)
2024-11-03		Matthieu Bachschmidt
Gonachon		Celestron C11
SBIG ST8XME / AstrodonExoPlanet-BB / 120.0		0.04 ± 1.14
Qatar-4b (LOW)
2024-10-25		Robert Roth
TURMX Observatory		CFF Telescopes 160mm APO
ZWO ASI6200MM Pro / Lum / 120.0		1.25 ± 0.85
Qatar-4b (LOW)
2024-10-24		Adrian Jones
Private Observatory (I64)		Meade ACF 30cm
QSI 583 / Lum / 200.0		-0.6 ± 1.22
Qatar-4b (LOW)
2024-09-28		Massimiliano Mannucci
Osservatorio Astronomico Margherita Hack		Celestron C14
SBIG ST10 XME / R / 240.0		-0.61 ± 1.18
Qatar-4b (LOW)
2024-09-17		John Collins
JC_Wrexham		Meade LX200GPS
ASI-290m / rpr / 60.0		-3.57 ± 2.02
Qatar-4b (LOW)
2024-09-08		Enrique Arce
Vallbona Observatory		Ritchey Chretien
ZWO ASI 294 MM PRO / Lum / 300.0		-0.14 ± 1.24
Qatar-4b (LOW)
2024-08-30		Alberto Tomatis
Alto-Observatory		RC
QHY 268M / Lum / 67.0		1.53 ± 1.44
Qatar-4b (LOW)
2024-08-21		Matthieu Bachschmidt
Gonachon		Celestron C11
SBIG ST8XME / AstrodonExoPlanet-BB / 120.0		2.42 ± 1.58
Qatar-4b (LOW)
2024-08-21		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 120.0		-0.8 ± 1.17
Qatar-4b (LOW)
2024-08-12		Claudio Lopresti
Claudio Lopresti		Mak-Newton
CCD Sbig ST10xme / Lum / 240.0		1.88 ± 2.02
Qatar-4b (LOW)
2024-08-11		A.Rosich, JM. Llenas ||
Observatori de Pujalt		PW CDK20
ZWO ASI 2600MM Pro / gpr / 180.0		1.1 ± 1.44
Qatar-4b (LOW)
2024-08-11		Alberto García Sánchez
Rio Cofio		MEADE LX200 Classic
SBIG ST8-XME / Clear / 160.0		0.92 ± 1.27
Qatar-4b (LOW)
2024-08-02		Esteban Reina
Observatori de Masquefa		Meade LX200
ZWO ASI 294 MM Pro / R / 120.0		-4.77 ± 2.3
Qatar-4b (LOW)
2024-07-14		Martin Crow
Burnham Observatory		Celestron C9.25
SX694 mono / Clear / 240.0		3.84 ± 1.34
Qatar-4b (LOW)
2024-07-05		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-2.81 ± 2.74
Qatar-4b (LOW)
2024-01-12		Ivo Peretto
MarSEC Marana Space Explorer Center		R-C
Moravia G2-1600 MkII / R / 150.0		-0.63 ± 1.73
Qatar-4b (LOW)
2024-01-03		Snaevarr Guðmundsson
Ness Observatory		Meade LX 200 ACF Schmidt-Cassegrain
SBIG STL 11000M / R / 120.0		-5.07 ± 1.58
Qatar-4b (LOW)
2023-12-25		Giuseppe Marino
Gruppo Astrofili Catanesi		Newtonian
SBIG ST-7 XME / Clear / 300.0		5.36 ± 1.43
Qatar-4b (LOW)
2023-12-16		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 120.0		1.57 ± 0.71
Qatar-4b (LOW)
2023-12-16		Francesco Scaggiante
Gruppo Astrofili Salese "GALILEO GALILEI"		NEWTON 410/1710
Player One Astronomy Poseidon-M Pro (IMX571) / R / 120.0		-3.28 ± 2.16
Qatar-4b (LOW)
2023-12-05		Snaevarr Guðmundsson
Ness Observatory		Meade LX 200 ACF Schmidt-Cassegrain
SBIG STL 11000M / R / 120.0		-2.74 ± 1.24
Qatar-4b (LOW)
2023-11-17		Claudio Lopresti
Claudio Lopresti		Meade LX200 12"
CCD Sbig ST9xe / I / 180.0		-0.8 ± 1.44
Qatar-4b (LOW)
2023-11-08		Emanuele Pavoni
Leavitt Observatory		RC
QHY268 / R / 150.0		2.54 ± 1.37
Qatar-4b (LOW)
2023-10-30		Nikola Antonov
Meshtitsa		Sky-Watcher Explorer PDS
ASI 533MM Pro Mono CMOS / V / 60.0		-0.45 ± 2.59
Qatar-4b (LOW)
2023-10-18		Bryan Martin
Tiger Butte Observatory Remote		AG Optical IDK
ZWO ASI 294 / Lum / 180.0		4.37 ± 1.87
Qatar-4b (LOW)
2023-10-01		Marco Stefanini
Osservatorio Aldebaran		Celestron C14
QHY294M Pro / Lum / 150.0		-2.0 ± 1.44
Qatar-4b (LOW)
2023-09-22		Mark Salisbury
POST		Orion Optics ODK
SBIG ST-10 XME / Clear / 240.0		0.1 ± 0.4
Qatar-4b (LOW)
2023-09-21		Manfred Raetz
privat observatory Herges-Hallenberg		SCT 280/1850 (C11 with Starizona reducer)
Moravian Instruments G2-1600 / AstrodonExoPlanet-BB / 120.0		1.32 ± 0.95
Qatar-4b (LOW)
2023-09-03		Simon Dawes
William James II		Celestron Edge11 HD
Risingcam Monochrome SONY imx571 / Lum / 300.0		4.37 ± 1.73
Qatar-4b (LOW)
2023-08-25		samuel Diaz Lopez
Tomas Lopez (Astrocamp)		N-AG8
ASI533MM / AstrodonExoPlanet-BB / 120.0		-0.73 ± 1.28
Qatar-4b (LOW)
2023-08-25		Ramon Naves
Montcabrer		Meade LX200 12" ACF
Moravian G4-9000 / Clear / 180.0		-1.79 ± 1.58
Qatar-4b (LOW)
2023-07-28		Dim Stouraitis
Galilaios		SCT
SXVF-H9 Starlight-Xpress / R / 180.0		0.02 ± 1.58
Qatar-4b (LOW)
2023-06-30		Adam Popowicz
Otivar dome2		Newton 12" ASA
ASI ZWO 1600MM / R / 240.0		-3.11 ± 2.02
Qatar-4b (LOW)
2022-12-18		Adam Popowicz
Otivar dome2		Newton 12" ASA
ASI ZWO 1600MM / R / 240.0		-0.3 ± 1.58
Qatar-4b (LOW)
2022-11-23		Vikrant Kumar Agnihotri
Cepheid Observatory India		GSO Ritchey–Chrétien
SX-35 TRIUS mono (KAF11002) / Lum / 120.0		0.13 ± 3.31
Qatar-4b (LOW)
2022-11-20		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		-0.88 ± 0.76
Qatar-4b (LOW)
2022-11-10		Jean-Claude MARIO
Observatoire de la Cabergue		T 500 Cassegrain "Arp 83"
ASI 6200 MM / Clear / 240.0		-0.88 ± 0.45
Qatar-4b (LOW)
2022-10-14		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 180.0		0.57 ± 2.16
Qatar-4b (LOW)
2022-10-13		Adam Popowicz
Otivar dome2		Newton 12" ASA
ASI ZWO 1600MM / R / 240.0		1.39 ± 5.18
Qatar-4b (LOW)
2022-10-05		Alessandro Marchini
Astronomical Observatory University of Siena		Mak-Cas 0.3m f/5.6
Sbig STL-6303 / R / 300.0		-1.41 ± 1.58
Qatar-4b (LOW)
2022-10-05		Jacques Michelet
Claix		GSO Ritchey-Chrétien
QSI-632 / R / 180.0		-1.69 ± 1.08
Qatar-4b (LOW)
2022-09-06		Giovanni Calapai
Home Astronomical Observatory		Celestron 11 Schmidt-Cassegrain
Atik 314L+ / R / 120.0		0.06 ± 1.87
Qatar-4b (LOW)
2022-08-28		David Molina
Anunaki Observatory Z51		Schmidt Cassegrain
SBIG ST-9xe / Clear / 120.0		-0.63 ± 1.01
Qatar-4b (LOW)
2022-08-27		David Arnot
OSO PIRATE		PlaneWave Instruments CDK24 24 inch (610 mm) f/6.5 Corrected Dall-Kirkham Astrograph
FLI ProLine KAF-16803 / R / 80.0		-2.25 ± 0.98
Qatar-4b (LOW)
2022-08-09		David Molina
Anunaki Observatory Z51		Schmidt Cassegrain
SBIG ST-9xe / Clear / 120.0		0.67 ± 0.86
Qatar-4b (LOW)
2022-08-09		Kevin Hills
Tacande		ASA 0.5m f/3.6 astrograph.
QHY 600M with IMX 455 chip / R / 60.0		0.53 ± 0.86
Qatar-4b (LOW)
2022-08-01		Claudio Lopresti
Claudio Lopresti		Mak-Newton
CCD Sbig ST10xme / Lum / 180.0		3.2 ± 4.32
Qatar-4b (LOW)
2022-07-03		Eric Miny
BLOIS SOLOGNE ASTRONOMIE OBSERVATORY		Newton T305
QSI 683WS / Lum / 180.0		-1.08 ± 2.59
Qatar-4b (LOW)
2022-01-27		Ian Sharp
Ham Observatory		Celestron C9.25 Edge HD
Starlight Xpress Trius Pro SX694 / R / 120.0		-4.29 ± 2.16
Qatar-4b (LOW)
2021-12-13		Francesco Scaggiante
Gruppo Astrofili Salese "GALILEO GALILEI"		NEWTON 410/1710
Custom made with KAF-1603ME CCD sensor / R / 120.0		3.2 ± 1.73
Qatar-4b (LOW)
2021-12-13		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 120.0		0.61 ± 0.72
Qatar-4b (LOW)
2021-12-13		Dominique DANIEL
La Montjoie		Celestron CGX C8 XLT
Camera CMOS ZWO ASI294MC pro (color) / Clear / 240.0		-2.13 ± 3.46
Qatar-4b (LOW)
2021-12-11		Aziz Ettahar Kaeouach
High Atlas Observatory		PlaneWave CDK 12.5
Zwo asi 294 mm pro / Lum / 120.0		1.56 ± 1.3
Qatar-4b (LOW)
2021-11-23		Stephen Futcher
Hampshire Astronomical Group, Clanfield		Ritchey-Chrétien (SX-46)
Starlight Xpress SX-46 / R / 120.0		0.9 ± 0.86
Qatar-4b (LOW)
2021-11-05		Valère Perroud
Observatoire de Duines		RC 10
Moravian G2-4000 / Lum / 180.0		-3.36 ± 1.87
Qatar-4b (LOW)
2021-10-29		Taewoo Kim
Deokheung Optical Astronomy Observatory		NYSC 1m Telescope
FLI PL-16803 or PI SOPHIA-2048B / R / 180.0		-0.83 ± 1.01
Qatar-4b (LOW)
2021-10-27		Thomas Mollier
Tomastro		Newtonian
ZWO ASI1600MMC / Clear / 120.0		0.7 ± 1.3
Qatar-4b (LOW)
2021-10-27		Jacques Michelet
Claix		GSO Ritchey-Chrétien
QSI-632 / Clear / 180.0		-0.31 ± 1.44
Qatar-4b (LOW)
2021-10-27		Didier Laloum
Observatoire Privé du Mont (OPM)		RC 8 GSO
Atik 383L+ / AstrodonExoPlanet-BB / 150.0		-1.89 ± 1.3
Qatar-4b (LOW)
2021-10-26		Robert Roth
TURMX Observatory		CFF Telescopes 160mm APO
ZWO ASI6200MM Pro / Lum / 120.0		-1.08 ± 1.15
Qatar-4b (LOW)
2021-10-18		Claudio Lopresti
Claudio Lopresti		Meade LX200 12"
CCD Sbig ST9xe / Lum / 180.0		-0.57 ± 3.46
Qatar-4b (LOW)
2021-10-17		Giorgio Baj
M57		Ritchey-Chretien
Sbig STT1603 ME / Clear / 180.0		1.83 ± 2.02
Qatar-4b (LOW)
2021-10-17		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 120.0		-1.77 ± 0.58
Qatar-4b (LOW)
2021-08-31		Kevin Hills
Tacande		ASA 0.5m f/3.6 astrograph.
QHY 600M with IMX 455 chip / R / 90.0		-0.38 ± 0.86
Qatar-4b (LOW)
2021-07-16		Dim Stouraitis
Galilaios		SCT
SXVF-H9 Starlight-Xpress / R / 90.0		1.06 ± 1.58
Qatar-4b (LOW)
2020-12-24		John Savage
Z42 Rushay Farm Observatory		Celestron 14Edge
ZWO ASI6200MM / R / 180.0		2.12 ± 1.3
Qatar-4b (LOW)
2020-11-18		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Lum / 120.0		-0.79 ± 0.86
Qatar-4b (LOW)
2020-11-07		Lorenzo Betti
Osservatorio Polifunzionale del Chianti		RC-80cm
Moravian G4 - KAF 09000 / V / 90.0		-1.39 ± 0.58
Qatar-4b (LOW)
2020-11-02		Taewoo Kim
Deokheung Optical Astronomy Observatory		NYSC 1m Telescope
FLI PL-16803 or PI SOPHIA-2048B / R / 120.0		-1.54 ± 0.58
Qatar-4b (LOW)
2020-09-13		Manfred Raetz
privat observatory Herges-Hallenberg		SCT 280 /1790 (Celestron C11 with reducer)
Moravian Instruments G2-1600 / Clear / 120.0		0.03 ± 1.01
Qatar-4b (LOW)
2020-08-25		Anaël Wünsche
Observatoire des Baronnies Provençales		Astelco2
ZWO ASI6200 / Clear / 120.0		1.24 ± 0.43
Qatar-4b (LOW)
2020-08-25		Alberto Tomatis
Alto-Observatory		RC
STL 6303 / Lum / 240.0		0.09 ± 0.72
Qatar-4b (LOW)
2020-08-25		Vojtěch Školník
Hvezdarna Valasske Mezirici		Meade LX90 ACF
Meade DSI II / Clear / 180.0		-0.05 ± 1.01
Qatar-4b (LOW)
2020-08-25		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.2 ± 0.86
Qatar-4b (LOW)
2020-07-28		Francois Regembal
HRTobs		Astrosib RC360
SBIG STX 16803 / Lum / 60.0		-0.16 ± 1.3
Qatar-4b (LOW)
2020-07-10		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		3.5 ± 1.15
Qatar-4b (LOW)
2020-07-10		Marc Bretton
Observatoire des Baronnies Provençales		Astelco 800mm
ZWO ASI6200 / Clear / 120.0		-0.25 ± 0.72
Qatar-4b (LOW)
2020-01-07		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.2 ± 1.87
Qatar-4b (LOW)
2019-11-21		Ferran Grau Horta
Ca L'Ou		Meade ACF 16''
FLI Proline PL1001 / Clear / 300.0		0.04 ± 1.87
Qatar-4b (LOW)
2019-11-12		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.08 ± 1.44
Qatar-4b (LOW)
2019-10-16		Mario Morales-Aimar
Observatorio de Sencelles MPC K14		10" Meade Schmidt Cassegrain
SBIG ST7-XME / Clear / 500.0		3.61 ± 1.3
Qatar-4b (LOW)
2019-10-07		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.11 ± 1.15
Qatar-4b (LOW)
2019-10-06		Anaël Wünsche
Observatoire des Baronnies Provençales		Astelco
FLIPL230 / Clear / 120.0		2.43 ± 0.43
Qatar-4b (LOW)
2019-10-06		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.16 ± 0.72
Qatar-4b (LOW)
2019-09-17		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-1.83 ± 1.15
Qatar-4b (LOW)
2019-08-21		Dim Stouraitis
Galilaios		SCT
SXVF-H9 Starlight-Xpress / R / 60.0		-0.73 ± 1.3
Qatar-4b (LOW)
2019-07-23		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-3.0 ± 1.01
Qatar-4b (LOW)
2019-01-20		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		-0.36 ± 1.15
Qatar-4b (LOW)
2019-01-02		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		2.29 ± 1.58
Qatar-4b (LOW)
2018-12-24		Yves Jongen
Rasteau Observatory		Plane Wave CDK 17"
SBIG STXL 11002 / Clear / 120.0		2.46 ± 0.86
Qatar-4b (LOW)
2018-01-24		Anaël Wünsche
Observatoire des Baronnies Provençales		Astelco
FLIPL230 / Lum / 120.0		0.22 ± 0.43
Qatar-4b (LOW)
2017-09-05		Marc Deldem
Les Barres Observatory		Celestron C8
SBIG ST8-XME / Clear / 150.0		-2.23 ± 1.73
Qatar-4b (LOW)
2016-12-30		Claudio Lopresti
Claudio Lopresti		Makutov-Cassegrain
CCD Sbig ST8xme / R / 240.0		-0.02 ± 2.02

Space Observations
Planet
Observation Date		 Mission O-C
minutes
Qatar-4b (LOW)
2022-10-29		TESS1.58 ± 1.24
Qatar-4b (LOW)
2022-10-27		TESS-0.48 ± 1.3
Qatar-4b (LOW)
2022-10-25		TESS0.93 ± 1.18
Qatar-4b (LOW)
2022-10-23		TESS-1.18 ± 1.14
Qatar-4b (LOW)
2022-10-20		TESS1.17 ± 1.28
Qatar-4b (LOW)
2022-10-18		TESS-1.44 ± 1.28
Qatar-4b (LOW)
2022-10-16		TESS-0.24 ± 1.44
Qatar-4b (LOW)
2022-10-09		TESS0.62 ± 1.3
Qatar-4b (LOW)
2022-10-07		TESS0.65 ± 1.73
Qatar-4b (LOW)
2022-10-05		TESS1.64 ± 1.44
Qatar-4b (LOW)
2022-10-04		TESS1.6 ± 1.27
Qatar-4b (LOW)
2022-10-02		TESS-2.3 ± 1.14

Literature Mid-times
Planet
Observation Date		 Reference O-C
minutes
2018-07-17 Mallonn et al. 2019 -1.41 ± 1.48
2017-11-13 Wang et al. 2021 -0.29 ± 1.02
2016-09-06 Alsubai et al. 2017 -2.16 ± 0.66
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