Welcome on the homepage of the VVS Working Group Variable Stars (VVS WVS).

The Working Group Variable Stars is one of the working groups of the Vereniging Voor Sterrenkunde (VVS), a Belgian amateur astronomical association. The Working Group Variable Stars groups VVS members interested in observing and studying objects that vary in brightness, most of these objects are variable stars but also active galactic nuclei and GRBs among others are included.

On these webpages you'll find information on the working group, the objects of interest, observing techniques, how to report observations, an online DB containing our observations, an online light curve generator etc.

The sudden outburst of GK Per has not reached his expected maximum brightness. Because this outburst was earlier then expected it was possible that GK Per wouldn't reach his maximum brightness. The maximum that was observed in our workgroup is magnitude 12.1. The maximum found in the AAVSO DB is 11.9. This is much fainter then the previous outbursts which reached magnitude 10. Meanwhile GK Per has reached again his minimum brightness of somewhat fainter then magnitude 13. It is always possible that GK Per will undergo some re-brightening. So keep on watching this star!

GK Per (Nova Per 1901) is since 10 september 2008 undergoing again an outburst. The last time it went in outburst was on 05/12/2006. This old nova shows regular outburst with an interval of 3 years. But with the last two outburst this tendency is not longer true. Between the last two outbursts, the time interval isn't even two years. It will also be possible that the maximum magnitude of magnitude 10 won't be reached. As always with variable stars, everything is possible. Keep on watching!
Charts for observing GK Per are free to download at the AAVSO website trough the VSP : http://www.aavso.org/observing/charts/vsp/
Information about how to observe and report the observations can you find in the left section of our website.
All GK Per observations dating back to 1979 are available from our online databank.

IAUC 8934 announced the discovery of a nova in Cygnus.

The nova has been discovered by the Japanese observers Koichi Nishiyama and Fujio Kabashima on two 20 second unfiltered CCD images taken on Apr. 10.728 UT. The discoverers used a 105mm (f/5.6) photolens. Their images show the nova at magnitude 7.7. Nothing is visible on images made on Apr. 3.717 UT en Apr. 7.727 UT with a limiting magnitude of resp. 12.5 and 12.7.

The nova has also been discovered independently by the Chinese observers Z.-w. Jin and X. Gao on several 60s images taken with a EOS-350D camera equiped with a 200 mm f/2.8 telelens. The images with a limiting magnitude of ~15 were taken at Xingming Observatory, Mt. Nanshan on Apr. 10.831 UT. Nothing is visible on images taken on Apr. 8.831 UT with a limiting magnitude of ~14.

According to E. Guido en G. Sostero (Remanzacco, Italy), a Palomar Oschin Schmidt telescope plate taken on 1995 Aug. 3 shows a star with red magnitude 18 on the position of the nova. According K. Kadota (Ageo, Saitama-ken, Japan) also the USNO B1.0 catalogue contains a star at position R.A. 19h43m02s.039, Dec. +32o19'13".84 with red magnitudes 15.5 and 16.3. The epoch for these magnitudes is evidently from the Palomar Sky Survey plates.

In CBET 1334 K. Ayani, Bisei Astronomical Observatory (BAO) and K. Matsumoto, Osaka Kyoiku University announced that low resolution spectra taken with the 1.01 BAO telescope shows prominent broad Balmer emission lines, which indicate that the object is a nova in its early phase of outburst.

N. N. Samus, Institute of Astronomy, Moscou, announced in IAUC 8934 that the nova was assigned the variable-star designation V2491 Cyg.

The position as measured by Koichi Nishiyama en Fujio Kabashima using a 40cm reflector:
R.A. = 19h 43m 01.96s, Decl. = +32d 19' 13.8" (J2000.0)

More details are given in IAUC 8934 and CBET 1334.

Reported VVS observations
V2491 Cyg observations
V2491 Cyg light curve
V2491 Cyg spectra

Information for observers
Charts for observers
AAVSO VSP Charts (Chart code cfr upper right hand box):
V2491 Cyg, FOV 3° (b-scale)
V2491 Cyg, FOV 3° (b-scale), reversed

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

From April 10th to April 13th 2008, the AAVSO and BAA organised a joint meeting in Cambridge, UK. A number of VVS members attended this excelent meeting. The meeting started at Thursday evening with a dinner in New Hall. After the dinner the old telescopes of the Cambridge Institute of Astronomy could be visited.
The scientific paper sessions were scheduled on Friday and Saturday. After the banquet on Saturday, Arne Henden presented the AAVSO awards. BAA VSS Director Roger Pickard received the award of honorary AAVSO membership, Arto Oksanen received a Gamma-Ray Burst Award for discovering the optical afterglow of GRB 071010B. Arne Henden also presented the observer awards, our member and founder Frans Van Loo received the 25000 visual observations award. Gary Poyner received the Charles Butterworth award from the VSS Director Roger Pickard.
On Sunday a trip to Stonehenge and Avebury was organised.
An extensive report on this meeting will be published in Heelal.
Pictures are online available.

CBET 1291 followed by IAUC 8927 announced the discovery of a nova in Cygnus.

The nova has been discovered by Hiroshi Kaneda on nine 4-s unfiltered images taken on Mar 7.801 UT, using a digital camera equiped with a 105mm f/2.5 telephoto lens. Nothing was visible on images taken on October 5th 2007, Januari 1st 2008 and February 18th. The limiting magnitude was ~10.5.
Nothing is visible on DSS plates within 20" of this nova to mag 13.0.

CBET 1291 mentions that following the announcement of a possible nova on the Central Bureau for Astronomical Telegrams' unconfirmed-objects webpage, numerous additional claims of independent discovery have been received.
The first report came from Zhang-wei Jin and Xing Gao, Xingming Observatory, Mount Nanshan, China. They discovered the nova using a Canon EOS 350D camera equiped with a 200 mm f/2.8 telephotolens (7-cm objective) on Mar. 7.881 UT and reported a mag ~8.1. Their images taken on Mar. 2 and 5 don't show the nova. The images are available via http://www.xjltp.com/XM08AD.htm.
Refer to CBET 1291 and IAUC 8927 for detailes information.

In IAUC 8928 N. N. Samus, Institute of Astronomy, Russian Academy of Sciences announced that the nova has been assigned the variable-star designation V2468 Cyg.

Position of the nova measured by K. Kadota (Ageo, Japan) using a 25cm reflector:
19h 58m 33.39s +29d 52' 06.5" (J2000)

Reported VVS observations
V2468 Cyg observations
V2468 Cyg light curve

Information for observers
Charts for observers
AAVSO VSP Charts (Chart code cfr upper right hand box):
N Cyg 08 (for usage with binoculars)
N Cyg 08, FOV 5.8° (upside-down, for usage without zenith prism)
N Cyg 08, FOV 5.8° (reversed, for usage with zenith prism)
N Cyg 08, FOV 1° (d-scale)
N Cyg 08, FOV 1° (d-scale), reversed

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

CBET 1181 announces the discovery of a nova in Vul. After V458 Vul, this is the second nova discovered in the Vulpecula constellation this year.

Hiroshi Kaneda from Japan discovered the nova on three 4-s unfiltered images taken on Dec 25.35 UT using a Nikon D40 digital camera equiped with a 105mm f/2.5 telelens. At the moment of discovery the nova was at magnitude ~8.7. Nothing is visible within 20" arround this nova on DSS plates. Also on images taken by Kaneda on earlier dates, nothing is visible with a limiting magnitude of 10-11.
Akihiko Tago discovered the nova independently on images taken on Dec. 26.38 UT using a Canon 20D digital camera and Pentax 105mm f/3.2 lens. The magnitude of the nova was ~8.3.

De position of the nova as measured by K. Itagaki on CCD frames made using a 60cm f/5.7 reflector:
19h 48m 08.84s +21d 15' 27.6" (J2000)

N. N. Samus en E. Kazarovets, Institute of Astronomy, Russian Academy of Sciences, announced that this nova is being given the designation V459 Vul.

Reported VVS observations
V459 Vul observations
V459 Vul light curve

Information for observers
Charts for observers
Charts can be plotted with the AAVSO Variable Star Plotter: V459 Vul

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

HS 2331+3905 is a unique cataclysmic variable never observed in outburst before. Up to now the star does not have an official GCVS designation yet, the name HS 2331+3905 refers to the Hamburg Quasar Survey catalogue.

Hiroyuki Mehara discovered the outburst at V = 14.59 on Sep. 4.775 UT and announced it via VSNET (vsnet-alert 9530). M. Uemura, A. Arai, M. Sasada en O. Nagae, KANATA team, Hiroshima University could confirm the outburst soon after the discovery (vsnet-alert 9531). In the following 24 hours the star brightened up to magnitude 9. In quiesence the star is about magnitude 16.5.

HS 2331+3905 is probably a member of the WZ Sge stars. WZ Sge stars show outburst with a very large amplitude, but the outburst are rare. This star is a very interesting one since the white dwarf in the system shows ZZ Ceti pulsations (Araujo-Betancor et al., 2005, A&A 430, 629).

Reported VVS observations
HS 2331+3905 observations
HS 2331+3905 light curve

Information for observers
Charts for visual observers
AAVSO VSP charts (chart code 070905):
HS 2331+3905 (b-scale)
HS 2331+3905 (c-scal)
HS 2331+3905 (d-scale)
HS 2331+3905 (e-scale)

HS 2331+3905, reversed (b-scal)
HS 2331+3905, reversed (c-scale)
HS 2331+3905, reversed (d-scale)
HS 2331+3905, reversed (e-scale)



More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

In IAUC 8863 N. N. Samus, Institute of Astronomy, Russian Academy of Sciences, announced that this nova has been given the designation V458 Vul.

CBET 1027 announced the discovery of a possible nova in Vulpecula by Hiroshi Abe. Abe discovered the nova on images taken on Aug. 8.54 UT using a Canon EOS Kiss Digital Camera with a 35-mm f/2.8 Pentax lens.
The nova was of magnitude 9.4 at the time of discovery. The 30s exposures gave a limiting magnitude about 11.5. Nothing was visible on Abe's images taken on July 23 and 31 and Aug. 4.

De position measured by K. Kadota on CCD images taken with a 25cm f/5 reflector:
19h 54m 24.64s +20d 52' 51.9" (J2000)

Kadota adds that the USNO-A2.0 catalogue contains a star of r=18.1 and b=17.6 on position 19h 54m 24.66s +20d 52' 51.7".

Reported VVS observations
N Vul 07 observations
N Vul 07 light curve

Information for observers
Charts for visual observers:
AAVSO VSP charts (chart code 070902):
N Vul 07 (b-scale)
N Vul 07 (c-scale)
N Vul 07 (d-scale)
N Vul 07 (e-scale)

N Vul 07, reversed (b-scale)
N Vul 07, reversed (c-scale)
N Vul 07, reversed (d-scale)
N Vul 07, reversed (e-scale)

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

R CrB, the prototype of the R Coronae Borealis stars shows a decline for the first time since february 2003. Unpredictable sudden fadings is the most prominent feature of these stars. R CrB may fade up to 8 magnitudes in a few weeks. In 2003 R CrB faded in about 3 weeks from 6th magnitude to 13th magnitude. The star returned to maximum brightness by May 2003. The current fading started arround July 7th. It is uncertain whether the star will show a deep minimum or not. Currently the star can be easily observed using binoculars, later on a telescope may be required. R CrB can be easily located.
More information on R CrB can be read in the AAVSO Variable Star of the Month, January 2000.

Reported VVS observations
R CrB observations
R CrB light curve
More observations are available through our online DB or light curve generator.

The 2003 fading : R CrB 2003 light curve

Information for observers
Charts voor visual observers
AAVSO charts are available:
R CrB AAVSO charts

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations



Luc Janssens imaged R CrB on July 24th at 23h53 UT. R CrB is approximately equally bright as the 7.4 magnitude comparison star just NW of R CrB.

Click to enlarge.
Image: Luc Janssens (Nikon D70, Nikor 80-200mm op 80mm, f/2.8, 15sec, iso 1600)

The KNVWS and VVS Working groups Variable Stars gathered for a Variable Stars Day on 12 May 2007. The location for the meeting was the Jan Paagman Sterrenwacht, Ostaderstraat 28, Asten, Netherlands (approx. 20 km east of Eindhoven, NL).

Pictures and presentations of the Variable Stars Day are now online available.

Thanks to the KNVWS-WVS for organising this meeting!

click to enlarge
At the VVS membership meeting held in Gent on April 14th two variable star observers received the Galilei awards. The Galilei awards are presented to VVS members who made significant contributions to the VVS.

Wim Pessemier (right) received the bronze Galilei Award for his dedicated efforts in the local astronomical youth club JVS Sirius and for his contributions of Variable Star Observations. The bronze Galilei award is presented to a youngster as an incentive.

The Silver Galilei award was presented to Johan Van Der Looy (left). Using his binoculars Johan observes mainly variable stars. During the past 15 years he reported about 44000 variable star observations. Johan regularly writes articles for Heelal, the monthly magazine of the VVS. He also gives presentations during the meetings of the VVS WVS and the VVS/JVS weekend.

Akihiko Tago discovered a possible nova in Cygnus on March 15th. He found a "new" star of magnitude 7.4 on images taken with a Canon 20Da digital camera (+ 70-mm f/3.2 lens; limiting magnitude 13.2 +/- 0.2). Nothing was visible at the same position on images of March 12th with a limiting magnitude of 12.
Low resolution spectra obtained with the 1.01 meter telescope of the Bisei Astronomical Observatory (BAO) and low resolution spectra obtained with the 2 meter NAYUTA telescope of the Nishi-Harima Astronomical Observatory confirm the nova nature.

The nova has been given the official designation V2467 Cyg.

K. Nishiyama and T. Sakamoto, Bisei Spaceguard Center, reported following position:
R.A. = 20h 28m 12.52s, Decl. = +41o 48' 36.5" (2000.0)

A red USNO-catalogued star is located at position R.A. = 20h 28m 12.505s, Decl. +41o 48' 36.69s (red mag 18.5).

References:
CBET 890, CBET 891, IAUC 8821

Reported VVS observations
The Belgian weather prevented observations during the first week following the discovery announcement.
V2467 Cyg observations
V2467 Cyg light curve

Information for observers
Charts for visual observers
AAVSO VSP charts:
V2467 Cyg (FOV = 1°, faintest comp star = 13.7)
V2467 Cyg (FOV = 0.5°, faintest comp star = 15.3)

V2467 Cyg, reversed (FOV = 1°, faintest comp star = 13.7)
V2467 Cyg, reversed (FOV = 0.5°, faintest comp star = 15.3)

Older AAVSO VSP charts, still usefull to locate the nova:
V2467 Cyg (FOV = 3°, faintest comp star = 9.6)
V2467 Cyg (FOV = 2°, faintest comp star = 9.6)

V2467 Cyg, reversed (FOV = 3°, faintest comp star = 9.6)
V2467 Cyg, reversed (FOV = 2°, faintest comp star = 9.6)

BVRI sequence for CCD observers
Following preliminary sequence for CCD observers is available from the AAVSO FTP site: AAVSO BVRI sequence.


More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

Recent observations show a brightening of GK Per (Nova Per 1901).
This old nova displays an outburst pattern resembling those of dwarfnovae. The duration of GK Per's outbursts are however longer than those of dwarfnovae. Usually the rise to maximum brightness takes about one month.
The last outburst of GK Per dates back to the second half of 2004. That outburst was somewhat unusual, the rise to maximum brightness took about 2 months and happened in two stages with a minor fading in between. This is clearly shown in our light curve.
The recurrence time of the outbursts is usually about 3 years. The current brightening comes somewhat earlier than expected and it is unclear whether GK Per will show a normal outburst.


Reported VVS observations
GK Per observations from 1 dec 2006 on
GK Per light curve from 1 juni 2004 on

All GK Per observations dating back to 1979 are available from our online DB.

Information for observers
Charts for visual observers
AAVSO charts are available.
Please use these charts to observe this star:
AAVSO charts

More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

BV sequence for CCD observers
Following sequence for CCD observers is available from the AAVSO website: AAVSO BV sequence.

After a re-brightening phase which started in July 2006, V2362 Cygni is rapidly fading.
In CBET 769, U. Munari et al. announced that the current decline started around Nov. 30.2 UT. The light curve is very similar to the one of V1493 Aql (Nova Aql 1999). Light curves of both novae composed with observations from the VVS WVS members are available at the links below. Note that the time scale and magnitude scale is different. The re-brightening phase for V2362 Cygni took much longer than for V1493 Aql. The amplitude of the re-brightening is only slightly larger for V2362 Cyg. Observations are available from our online database or directly via the links given below. More information on this nova can be found on the AAVSO website.

Reported VVS observations
V2362 Cyg observations
V2362 Cyg light curve

Compare the light curve with the one of V1493 Aql:
V1493 Aql observations
V1493 Aql light curve

Information for observers
Charts for visual observers
The AAVSO has a chart available.
Please use this chart for your observervations:
d-chart
reversed d-chart

AAVSO VSP chart up to magnitude 15
reversed AAVSO VSP chart up to magnitude 15

BVRI sequence for CCD observers
Following sequence for CCD observers is available from the AAVSO FTP site: AAVSO BVRI sequence.
More information on observing variable stars and reporting observations:
Observing variable stars
Reporting observations

BVRI sequence for CCD observers
Following sequence for CCD observers is available from the AAVSO FTP site: AAVSO BVRI sequence.

The Variable Stars Day organised on Saturday 13 May 2006 was very succesful.
About 20 participants gathered at the Europlanetarium in Genk, among them colleagues from the Dutch KNVWS WVS and one from the German BAV. We were pleased to have AAVSO Director Dr. Arne Henden as guest lecturer on our meeting.

Pictures and presentations (partly) of the Variable Stars Day are now online available.

Thanks to all participants, speakers, everyone who helped organising this meeting and the Europlanetarium for providing the meeting room.

N. N. Samus, Russian Academy of Sciences, announced in IAUC No. 8698 that the nova has been assigned the official designation V2362 Cyg.
The same IAUC reports also that low resolution spectra taken by several Japanese observers suggest a classical nova caught at or slightly before its maximum light.

The AAVSO released improved charts to observe the nova:
http://www.aavso.org/cgi-bin/searchcharts3.pl?name=n%20cyg%2006.

Observations made by the VVS WVS observers can be plotted with the VVS WVS light curve generator or retrieved from the VVS WVS online DB using the starname V2362 Cyg.

The discovery of the nova by H. Nishimura (Miyawaki, Kakegawa, Japan) had been announced by the Central Bureau of Astronomical Telegrams (CBAT) in IAUC No. 8697.

Nishimura found the new object (mag 10.5) on two Kodak T-Max 400 films taken on Apr. 2.807 UT using a Pentax 6x7 camera (+ 200-mm f/4.0 lens; 60-s exposures).
Nothing was present at this location on his films taken on Mar. 28 (limiting mag 12) or on earlier patrol films back to Oct. 2001.
On request of the AAVSO R. Miles (Stourton Caundle, Dorset, Engeland) confirmed the existence of the object with a CCD image taken on Apr. 4.995. Miles reported a magnitude of V = 8.5 +/- 0.3 and following precise position:

R.A. = 21h11m32.34s, Decl. = +44o48'03".9 (uncertainty +/- 0.3", equinox 2000.0).

Miles states that nothing is visible at this location on a Digitized Sky Survey image.

The recurrent nova RS Oph went in outburst for the first time since 1985.

The outburst has been discovered by the Japanese observers Kiyotaka Kanai (Gunma,Isezaki-shi) and Hiroaki Narumi (Ehime,Kita-gun) and was reported on the VSNet-Alert mailing list. H. Narumi estimated the brightness on Feb. 12.829 UT at magnitude 4.5 and K. Kanai somewhat later at magnitude 4.6.

The previous outburst dates back from 28th Januari 1985 when RS Oph reached a maximum magnitude of 5.4. The recurrence time (time interval between outbursts) differs a lot from one outburst to the other. Other outbursts have been observed in 1898, 1933, 1958, 1967 and 1985. The behavior during the outbursts is surprisingly similar in nature.

Typically RS Oph brightens from minimum (around magnitude 11.5) to maximum in less than 24 hours. The star fades in 3 stages, during the first ~40 days the star fades at about 0.1 magnitudes per day, followed by a slower decline at about 0.02 mag/day during 40 a 50 days. During the last stage the star fades again more quickly at about 0.05 mag/day. The duration of the complete outburst takes about 100 - 120 days. During quiescence the star displays variations with an amplitude of 1 to 3 magnitudes.

Only 2 observations of the 1985 outburst could be reported by Frans Van Loo to the VVS WVS. Hopefully this time more VVS WVS observers will be able to observe this interesting object.

Please use the most recent AAVSO charts to make your observations. The charts are available here.

More information on RS Oph:
AAVSO VSOTM May 2000
AAVSO Alert Notice 335