Astrophotography by Anthony Ayiomamitis

Differential Photometry

A variable star, as its name suggests, is a star whose magnitude varies intrinsically, in contrast to eclipsing binaries whose magnitude varies as a result of one star in the binary system eclipsing the other. True variables are one of five types, namely Mira stars, semiregular stars, cepheids, eruptive variables and, finally, cataclysmic variables. Minimum to maximum magnitude can range from days to many months with some variables displaying irregular periods.

A popular method for the study of variable stars, particularly short-term variables, is by the use of the technique known as "differential photometry". Rather than measure the (variable) magnitude of a variable star on an absolute scale, measurements are made over time relative to one or more non-variable star(s) and these differences are then plotted so as to study and illustrate the relative or differential change in magnitude. Due to the very large number of variables stars, the field of differential photometry represents one of the key fields in astronomy whereby the amateur astronomer can make a meaningful and long-lasting contribution to both science and astronomy.

More recently, the search for extrasolar planets (over 925 discovered so far) has identified yet another interesting application for the practice of differential photometry whereby the minute drops in magnitude of a star hosting an exoplanet are studied. Further details for the interested party are available here.

Note: For an excellent article on exoplanets, see S&T (Feb/2006: 28-34) and Astronomy Magazine (Oct/2006: full issue). Similarly, for an excellent article on observing variable stars, see Astronomy Magazine (Nov/2007: 56-59). Finally, for an article on "hot Jupiters", see Astronomy Now (April/2010: 40-41).


Exoplanet Light Curves
CoRoT-1b in Mon

2010-02-04     ----------
CoRoT-2b in Aql

2008-06-06     2012-07-28
CoRoT-4b in Mon

2009-02-05     ----------
GJ 1214b in Oph

2010-06-29     2011-04-23
2012-06-25     ----------
HAT-P-1b in Lac

2009-09-03     ----------
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HAT-P-3b in UMa

2008-06-15     2011-03-24
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HAT-P-4b in Boo

2010-04-22     ----------
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HAT-P-5b in Lyr

2008-05-28     2011-06-23
2012-07-09     ----------
HAT-P-7b in Cyg

2008-06-03     ----------
HAT-P-8b in Peg

2009-08-27     ----------
HAT-P-10b in Ari

2008-10-09     ----------
HAT-P-12b in CVn

2009-05-13     ----------
HAT-P-14b in Her

2011-06-18     ----------
HAT-P-16b in And

2013-11-07     ----------
HAT-P-18b in Her

2011-05-13     ----------
HAT-P-19b in And

2011-11-19     ----------
HAT-P-20b in Gem

2011-12-02     ----------
HAT-P-22b in UMa

2013-03-04     ----------
HAT-P-23b in Del

2011-08-30     2012-07-20
HAT-P-25b in Ari

2012-01-02     ----------
HAT-P-32b in And

2012-09-12     ----------
HAT-P-37b in Dra

2013-06-09     ----------
HD189733b in Vul

2008-06-27     2012-07-07
HD 209458b in Peg

2008-09-02     2013-09-23
KELT-3b in LMi

2013-03-09     ----------
Qatar-1b in Dra

2012-07-04     ----------
Qatar-2b in Vir

2013-04-11     ----------
TrES-1b in Lyr

2008-07-08     ----------
TrES-2b in Dra

2008-05-15     2012-05-29
TrES-3b in Her

2008-05-03     2011-05-20
TrES-4b in Her

2008-06-07     2013-06-29
TrES-5b in Cyg

2013-08-06     ----------
WASP-1b in And

2008-09-06     2013-11-09
WASP-2 in Del

2012-07-30     ----------
WASP-3b in Lyr

2008-06-13     2012-07-05
WASP-10b in Peg

2008-08-28     ----------
WASP-11b in Ari

2008-10-09     ----------
WASP-12b in Aur

2011-01-14     2011-12-03
WASP-14b in Boo

2010-05-01     ----------
WASP-24b in Vir

2010-04-22     ----------
WASP-33b in And

2013-10-28     ----------
WASP-43b in Sex

2012-01-14     ----------
WASP-48b in Cyg

2011-07-07     ----------
WASP-52b in Peg

2013-10-20     2013-10-27
WASP-58b in Lyr

2013-07-24     ----------
XO-1b in CrB

2009-06-04     ----------
XO-2b in Lyn

2008-11-25     ----------
XO-3b in Cam

2008-11-20     ----------
XO-5b in Lyn

2010-03-25     ----------

Exoplanet Light Curves
HAT-P-13: Campaign for the search of the double planetary system HAT-P-13(b,c)
HAT-P-13b in UMa

2010-03-26
(OOT)
HAT-P-13b in UMa

2010-03-28
(full transit)
HAT-P-13b in UMa

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HAT-P-13b in UMa

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HAT-P-13b in UMa

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HD 213597: STEREO mission chance discovery of substellar companion
HD 213597b in Aqr

2011-08-20
(Ingress)
HD 213597b in Aqr

2011-08-25
(Ingress)
HD 213597b in Aqr

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HD 213597b in Aqr

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HD 213597b in Aqr

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Kepler Mission Exoplanet Candidate Light Curves
KOI-256b in Cyg

2011-07-08     2011-08-17
2011-08-28     ----------


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PAWM: Pro-Am White Dwarf Monitoring Project
WD0004+330 in And

2011-09-13     2011-09-14
WD0005+511 in Cas

2011-09-16     ----------
WD0134+833 in Cep

2011-09-17     ----------
WD2111+498 in Cyg

2011-09-12     ----------
WD2134+293 in Cyg

2011-08-18     2011-08-19
WD2147+280 in Peg

2011-09-01     ----------
WD2148+286 in Peg

2011-09-03     2011-09-04
WD2256+249 in Peg

2011-09-02     ----------
WD2309+105 in And

2011-09-16     ----------
WD2329+407 in And

2011-09-10     ----------
WD2341+322 in Peg

2011-09-11     ----------

Constellation Variable Star Light Curves
Andromeda
GSC 2290:1195

2012-10-05     ----------
GSC 2792:1770

2013-11-17     ----------
GSC 2792:1914

2013-11-07     2013-11-17
GSC 2815:1216

2013-10-21     ----------
GSC 2843:1999

2011-11-21     ----------
AB And

2007-11-08     ----------
GP And

2007-11-08     2012-12-01
GZ And

2007-12-03     ----------
V460 And

2011-12-01     ----------
V524 And

2012-10-01     ----------
V528 And

2013-09-08     2013-10-24
V544 And

2013-10-15     2013-10-21
Aquarius
GSC 0513:0624

2012-09-01     ----------
CY Aqr

2010-08-25     ----------
Aquila
GSC 1061:1651

2013-07-29     ----------
GSC 1076:0158

2012-08-05     ----------
NSVS 14243430

2012-07-06     ----------
Aries
GSC 1220:1131

2013-10-12     2013-11-08
Auriga
GSC 3755:0845

2012-01-03     ----------
Bootes
GSC 0914:0684

2013-05-01     ----------
GSC 2566:1398

2011-06-01     ----------
GSC 3043:0463

2012-06-16     ----------
GSC 3489:0868

2011-05-31     2011-06-16
TZ Boo

2008-05-27     ----------
YZ Boo

2011-05-25     ----------
V336 Boo

2012-06-11     ----------
Camelopardalis
GSC 4537:0689

2013-10-23     ----------
GSC 4556:1113

2013-04-27     ----------
BL Cam

2008-11-25     2011-11-28
2013-10-18     ----------
V435 Cam

2013-10-23     ----------
USNO-B1.0 1531-0149458

2013-10-18     ----------
Canes Venatici
GSC 3031:0307

2013-04-28     2013-04-29
2013-05-26    
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Canis Minor
GSC 0191:1282

2011-03-14     ----------
Cassiopeia
CW Cas

2012-09-23     ----------
NU Cas

2012-09-08     ----------
PS Cas

2012-09-09     ----------
V471 Cas

2012-09-02     ----------
V473 Cas

2012-09-04     ----------
V523 Cas

2007-12-02     ----------
V1031 Cas

2012-09-24     ----------
V1040 Cas

2012-09-08     ----------
V1107 Cas

2012-08-28     ----------
V1115 Cas

2012-09-02     ----------
V1138 Cas

2012-09-04     ----------
V1139 Cas

2012-09-09     ----------
Cepheus
GSC 3986:1266

2012-09-03     ----------
GSC 4464:0924

2012-08-04     ----------
GSC 4464:2476

2012-08-04     ----------
GSC 4500:0083

2012-08-06     ----------
NW Cep

2012-09-03     ----------
V789 Cep

    2013-07-23 ----------
V792 Cep

2013-06-17     2013-07-23
Coma Berenices
GSC 1442:1358

2011-04-22     ----------
Corona Borealis
AU CrB

2013-04-13     ----------
AV CrB

2013-05-14     ----------
Cygnus
GSC 2696:1396

2012-06-26     ----------
GSC 3934:1904

2012-06-22     ----------
EM Cyg

2013-05-26     ----------
XX Cyg

2010-08-28     ----------
V700 Cyg

2012-08-25     ----------
V798 Cyg

2013-07-25     ----------
V1191 Cyg

2012-09-05     ----------
V1193 Cyg

2013-08-06     ----------
V2455 Cyg

2012-06-28     ----------
Draco
GSC 3553:0845

2013-06-09     ----------
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GSC 4196:1784

2013-06-19     ----------
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----------     ----------
GSC 4237:0482

2013-06-20     2013-06-21
2013-06-24     2013-10-19
2013-10-22     2013-10-26
GSC 4237:0636

2013-06-20     2013-06-21
2013-06-24     2013-10-19
2013-10-26     ----------
GSC 4552:1498

2011-03-25     ----------
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LW Dra

2012-06-21     ----------
Hercules
GSC 1566:2802

2013-06-14     ----------
GSC 2043:1201

2011-05-06     ----------
GSC 2049:1164

2013-05-31     ----------
GSC 2080:0986

2012-06-10     ----------
GSC 2083:0228

2013-06-15     ----------
GSC 2083:1184

2013-06-15     ----------
GSC 2108:1564

2012-06-09     ----------
GSC 3074:0114

2011-03-19     ----------
GSC 3490:0814

2011-03-26     ----------
AH Her

2013-05-31     ----------
DY Her

2012-07-08     ----------
V879 Her

2013-06-15     ----------
V1086 Her

2012-06-29     ----------
V1116 Her

2012-06-02     2013-06-22
V1267 Her

2013-06-15     ----------
Hydra
KZ Hya

2011-02-08     ----------
Lacerta
IU Lac

2012-09-21     ----------
KZ Lac

2012-09-26     ----------
V441 Lac

2012-09-21     ----------
Leo
GSC 4923:0693

2011-04-03     ----------
Leo Minor
GSC 2996:0677

2013-03-09     ----------
GSC 2996:0858

2013-03-09     ----------
Libra
EH Lib

2011-04-23     ----------
Lynx
GSC 2496:0118

2013-04-12     ----------
SZ Lyn

2007-12-12     ----------
Lyra
GSC 3123:1050

2013-07-27     ----------
RR Lyr

2012-08-24/26     ----------
V400 Lyr

2013-08-11     ----------
V401 Lyr

2013-08-11     ----------
V507 Lyr

2013-08-24     ----------
V574 Lyr

2013-08-19     ----------
V579 Lyr

2013-08-01     ----------
V580 Lyr

2013-08-12     ----------
V582 Lyr

2013-07-27     ----------
V591 Lyr

2013-08-14     2013-09-08
V593 Lyr

2011-05-21     ----------
V596 Lyr

2013-08-23     ----------
Ophiuchus
GSC 0435:3806

2013-06-17     ----------
Pegasus
GSC 1147:0973

2013-03-13     ----------
GSC 1158:0921

2011-12-03     ----------
GSC 1716:1598

2012-10-07     ----------
NSVS 11672463

2012-09-07     ----------
BX Peg

2012-09-25     ----------
DY Peg

2007-12-01     2012-09-27
KW Peg

2012-09-25     ----------
U Peg

2007-12-07     ----------
V498 Peg

2013-08-13     ----------
Perseus
GSC 2861:0970

2013-10-11     2013-10-13
2013-10-26     ----------
Pisces
DW Psc

2012-11-13     ----------
GSC 0612:0771

2012-09-29     ----------
GSC 1750:1237

2012-09-28     ----------
Sagitta
GSC 1594:2234

2013-07-20     2013-09-05
2013-09-07     ----------
GSC 1621:1643

2013-07-18     ----------
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DL Sge

2013-07-20     ----------
Serpens
GSC 0933:0651

2013-06-16     ----------
GSC 1489:0914

2013-06-02     ----------
GSC 1489:1053

2013-06-02     ----------
GSC 5018:1085

2011-04-24     ----------
Triangulum
AX Tri

2013-10-25     2013-11-02
RZ Tri

2012-12-10     ----------
Ursa Major
GSC 3004:0870

2013-04-14     2013-04-17
GSC 3428:1497

2011-04-21     ----------
GSC 3441:1256

2013-03-04     ----------
GSC 3810:1553

2012-11-14     ----------
GSC 3832:0152

2012-06-03     ----------
GSC 3850:0137

2013-04-30     ----------
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GSC 3851:0240

2013-05-02     ----------
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GSC 4145:0857

2013-04-25     2013-05-24
----------     ----------
GSC 4145:0919

2013-04-19     2013-04-25
2013-05-04     2013-05-24
GSC 4145:0930

2013-04-19     2013-04-25
2013-05-04     2013-05-24
GSC 4163:0984

2013-04-26     ----------
AE UMa

2013-04-10     2013-04-11
GW UMa

2011-02-11     ----------
RV UMa

2013-04-30     ----------
UX UMa

2013-05-25     ----------
Ursa Minor
GSC 4417:0394

2011-06-17     ----------
YZ UMi

2012-06-13     ----------
Virgo
QV Vir

2011-03-12     ----------
Vulpecula
GSC 2194:2001

2013-07-19     2013-09-16
2013-10-23     ----------
DR Vul

2012-08-19     ----------
KN Vul

2012-08-22     ----------