The latest selection of observational data can be accessed through this link Here
This section illustrates a brief overview of a selection of some of the observational work conducted at Flarestar Observatory with the latest observations depicted at link above. Please consider any results shown here as preliminary as these are subject to change following a thorough analysis. Please consult the Scientific Publications page to find the final conclusions and/or confer with relevant organisations to acquire the latest findings.
Observation of exoplanet HAT-P-1b [2018 Aug 29] The exoplanet HAT-P-1b was observed by photometric means from Flarestar Observatory (IAU/MPC Code: 171) on 2018 August 29th. The brief report here under describes the event observed and results obtained. The exoplanet HAT-P-1b was observed by photometric means from Flarestar Observatory (IAU/MPC Code: 171) on 2018 August 29th. The brief here under describes the event observed and results obtained. On 2018 August 29th, the star ADS 16402 (also known as BD +37 4734 and HJ1832) at RA 22h 57m 46.8s , DECL. +38 40’ 28”, was monitored from Flarestar Observatory (San Gwann) in anticipation of a predicted transit event by the exoplanet HAT-P-1b. The 10.4 magnitude star system that is also a visual double star is estimated to be 453 light years away. It is classified as a G0V type star that is slightly hotter than the Sun. Prior to the observation run, calibration frames were taken in order to decrease noise inherent to the CCD camera as any subtle noise could easily mask the tiny drop in brightness. A Clear Blue-Blocking (CBB) filter was used to diminish atmospheric dispersion. The observation run commenced at 19:04 UT and was concluded at 22:58 UT. The gibbous moon rose above the horizon during the run at 19:25 UT but the CBB filter attenuated the bright moonlight. By the end of the observation session, 119 images of 90-second exposure each were acquired. These were later processed and analysed through the photometric software MPO Canopus. The data acquired showed that the observation run was successful and a transit event was recorded. The analysis of the data showed that the eclipse had a duration of 194.8 ± 12.9 minutes with a depth in magnitude of 0.0138 ± 0.0029. Mid-transit was derived to have occurred at HJD 2458360.39705 ± 0.00406 (21h 31m 45s UT). Figure 2 shows the eclipse event of HAT-P-1b as recorded from Flarestar. The light curve (graph) in black at the top shows the raw data. The middle light curve in blue shows the event where atmospheric extinction has been de-trended. The graph at the bottom shows the residuals of the light curve. The measured geometry of the system derived from the observations was in line with the Exoplanet Transit Database (ETD) catalogue. The diameter of the planet obtained from the observations of the 29th, yielded a planet radius of 1.223 (+0.122, -0.135) times as that of the radius of Jupiter with an orbital inclination of 87.51˚ (+1.32, -0.78). These results are consistent with those published on HAT-P-1b. Figure 3 shows the Observed minus Calculated (O-C) results against the epoch (time). This figure shows a trend that indicates that transit events are occurring late at a steady rate. This is possibly due to gravitational pull of another object(s) in the system. Astronomers utilise such observations to detect other planets in such systems through this technique. The figure below it shows that the transit depth in brightness as recorded from Flarestar Observatory is within the norm (dashed line) as recorded from other observatories. No marked decrease or increase in transit depth has been recorded. The upper right diagram in Figure 6 shows to scale the dimensions of the Sun and Jupiter. The lower left diagram within the same diagram depicts the geometry as extracted from catalog data whilst the one at right within the same diagram shows the interpretation according to the data as observed locally. The figure below shows an artist impression of the size of HAT-P-1b as compared with Jupiter and the Sun. HAT-P-1b orbits its parent star every 4.47 days in an orbit one-twentieth of the distance from Earth to the Sun. As a result, it has been estimated that the planet has a surface temperature of 1182 K that is far too hot to harbour any kind of life. HAT-P-1 was the largest known planet at the time of discovery in 2006. In spite of its huge size, its mass is only half that of Jupiter. |
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Observations of ASASSN-18ey (MAXI J1820+070) [March to Sept. 2018]
The transient ASASSN-18ey was first observed from Flarestar on 2018 March 20. This newly discovered transient has been the target of many observational campaigns. It was found that this transient is a low-mass X-ray binary in which the accreting object is suspected to be a black hole. Hence the variations in brightness are likely to be generated by in-falling material onto the accreting disc around the black hole. The rate of flow is rather inconsistent resulting in fast irregular fluctuations in brightness. These optical variations have also been correlated with X-ray observations. Although the flickering amplitude diminished during the last few weeks, an emergent oscillation emerged. M.Richmond through #ATEL 11596 produced a period of 3.4 hours, using observations from Flarestar. As the system evolved, further underlying periods could be discerned as oscillations became more pronounced. The lightcurves shown here depict the fast photometric fluctuations that were first observed and the later oscillations that developed later on. All observations were taken through CV band acquired from a 0.254-m SCT telescope working at f/6.3. The March 20 graph shows variation in brightness through 30 second exposures plus a download time of 11 seconds resulting in a cadence of 41 seconds (time interval between each data point). Sessions obtained later were based on 15,20 and 30 second exposures in 2X2 binned mode. Observations were reported to the AAVSO, CBA & VSNET for further analysis. The dataset of 2018 May 1st, was used in the analysis shown in Atel #11596. Other light curves from subsequent nights are depicted in no particular order. Prof. J. Patterson (CBA) issued Atel #11756 announcing a 17-hour period of ASASSN-18ey. Observations by CBA Malta (Flarestar) were used in the analysis. The position of this system is RA 18h 20' 21.95" DECL +07 11' 07.3" (2000) in the constellation of Ophiuchus. Shown here is a small subset of the light curves obtained from Flarestar. Over 65 nights of monitoring yielded a substantial amount of observations (>25K !!) for analysis. Monitoring of this star is ongoing. |
Observations of FO Aquarii [September 2018]
In response to AAVSO Alert Notice 644, the cataclysmic variable star is being observed every few nights in order to submit data for the campaign. The star is being monitored through a clear glass (C) filter using 60 second exposures. All images were taken through a 0.25-m SCT + Morovian G2-1600 CCD at -15C. More data is expected in the weeks. |
Monitoring of ASASSN-18bh
[2018 Jan.29 & 30] During the nights of January 29 and 30, the cataclysmic variable ASASSN-18bh was monitored from Flarestar. During the first night of observation on the 29th, the star was found to be at an average magnitude of 14.85 that exhibited superhump variation. On the subsequent night, the weather permitted longer monitoring times until the star reach 2 Airmass. This time, two phases of superhumps were detected that allowed the computation of P-sh as 0.0662 d +/- 0.0142 through the Lomb-Scargle algorithm. This result correlates well with that published by VSNET. |
The top-right graph on the left shows the phased lightcurve of ASASSN-18bh with the Period Spectrum for the Lomb-Scargle algorithm shown on the bottom-left corner. The weather was not so kind lately that hardly allowed the acquisition of observations during the last seven weeks. Hope that the weather will improve in the coming days.
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Participation in the PDS 110 Campaign [2017 Sept.09; 11; 13 ; 15 ; 16 ; 17]
PDS 110 is a young star in the constellation of Orion. Astronomers have found that a dust-enshrouded body eclipsed the star in 2008 & 2011, and expect that it will undergo an eclipse again in September 2017. In order to monitor the star during the event, a campaign is being conducted by the AAVSO in collaboration with other entities. It is believed that the eclipses are due to a ringed planet or brown dwarf that is orbiting the primary star. The rings around the secondary body are set to block an amount of starlight from the primary with the result that several dips in brightness are expected. Each ring will block the star's brightness in a different manner according to the density of the ring and the spaces between the rings (duration between subsequent dips) are also expected to differ. |
PDS 110 was observed from Flarestar Observatory on the above mentioned dates through V and I bands. The composite light curve shows that the eclipse did not occur at the expected dates but there remains a possibility that the event will occur later than predicted. However, a late occurrence is rather unlikely. Further monitoring will establish whether any events will happen. In case not, then the events that were earlier observed by astronomers may not be linked and thus any similar events happen on an irregular basis. In such case the ring hypothesis is likely to make way for a dust outburst that blocked the light from the star. Stay tuned for further updates. More information about the event can be accessed through the following links:
https://www.aavso.org/aavso-alert-notice-584
http://pds110.hughosborn.co.uk/
https://www.aavso.org/aavso-alert-notice-584
http://pds110.hughosborn.co.uk/
Monitoring of QR AND [2017 September 12]
QR Andromeda is a close supersoft binary star. Supersoft refers to the emission of super soft X-Rays by this binary system. This system was suggested for observation and hence monitoring has commenced for this variable star system.
The lightcurve shows that the period is rather long. AAVSO VSX states a P of 0.660451(15.8508 h) that implies that from a single location, the same phase will be facing the observer every two nights. hence there is no way that a composite lightcurve that shows the whole cycle is possible to obtain from a single longitude (unless a very long interval between observing runs is adopted). This star is quoted to vary between 11.4 and 13.2 V.
The lightcurve shows the results obtained through an all-night monitoring of the system. Exposures were of 60 seconds through a C-filter.
QR Andromeda is a close supersoft binary star. Supersoft refers to the emission of super soft X-Rays by this binary system. This system was suggested for observation and hence monitoring has commenced for this variable star system.
The lightcurve shows that the period is rather long. AAVSO VSX states a P of 0.660451(15.8508 h) that implies that from a single location, the same phase will be facing the observer every two nights. hence there is no way that a composite lightcurve that shows the whole cycle is possible to obtain from a single longitude (unless a very long interval between observing runs is adopted). This star is quoted to vary between 11.4 and 13.2 V.
The lightcurve shows the results obtained through an all-night monitoring of the system. Exposures were of 60 seconds through a C-filter.
Outburst of MASTER OT J212624.16+253827.2 [2017 AUG 28,29, 30]
The UGSU-type variable star MASTER OT J212624.16+253827.2 was reported to be in outburst and a monitoring session was carried out to obtain time series of this star system. The last outburst of this system occurred on 2013 and 2015, however it was reported that stage -A superhumps were missed. The lightcurves obtained from Flarestar Observatory show that the combined sessions show a P of 0.0927 +/- 0.0001 d. Data was analysed through MPO Canopus that employs the Fourier Analysis algorithm as developed by Dr. Harris A. All images were taken through a 10 inch SCT with an exposure of 60 seconds through a Clear Filter. |
Outburst of V701 Tauri [2017 Aug 21/22]
V701 TAU was reported to be in outburst by Eddy Muyllaert on 20170820.092 at magnitude 14.94 cv. The ASSASN Survey also reported the outburst that was recorded on 20170817.611 at mag 14.88V. In consideration that this star does not go into outburst so often, following a monitoring session to update the orbital period of the newly discovered variable star - GSC 00515-00187, the rest of the night was devoted to this interesting UGSU type star.
The star was monitored through 120 second exposures through a C filter. The resultant LC shows superhumps that are characteristic to SU UMa type variable stars. All data was sent to AAVSO & VSNET for further analysis.
V701 TAU was reported to be in outburst by Eddy Muyllaert on 20170820.092 at magnitude 14.94 cv. The ASSASN Survey also reported the outburst that was recorded on 20170817.611 at mag 14.88V. In consideration that this star does not go into outburst so often, following a monitoring session to update the orbital period of the newly discovered variable star - GSC 00515-00187, the rest of the night was devoted to this interesting UGSU type star.
The star was monitored through 120 second exposures through a C filter. The resultant LC shows superhumps that are characteristic to SU UMa type variable stars. All data was sent to AAVSO & VSNET for further analysis.
Observations of V Sagitta [2017 Aug 08 & 09]
V Sge was observed on August 8 and 9 through an all night session on the variable star. the star was monitored through two minute exposures using a V-Filter. Conditions on the second night were far from optimal as strong wind of 19 knots was registered during the observation. This have certainly influenced the outcome of the results obtained. This star is a CBSS-type variable that is made up of a close binary system. It is sustained that Super soft X-rays could be produced by this system due to high luminosity close binary interaction and by continuous nuclear burning on the surface of an accreting white dwarf (WD). |
Observations of TCP J18154219+3515598 in the constellation of Lyrae [2017 June 8 to July 20]
On the nights of June 8 and 9 a number of observations of the dwarf nova - TCP J18154219+3515598 were acquired. Images gathered through a C-filter were processed and reported in C-light (based on V band). All images up to June 14 were of 60 second integrations at a sensor temperature of -15C . Latter sessions had an exposure duration of 90 seconds. All images were calibrated through flat-field and dark frame corrections. Clouds interfered during some of the sessions, however the data still showed the superhumps of this system. All data was generated by MPO Canopus and reported to relevant associations. This data is being shown in its raw format and has been released for information purposes. The above lightcurve shows the sessions combined into one lightcurve that displays the system's brightness as it initially faded at an increasing rate. However, as Kato-san predicted, a re-brightening occurred as shown through the observations of 28 June 2017 to fade once again on 30th June.
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Observations of the nova-like variable star DQ Herulis [2017 May 28, 29 & 30]
On May 28th, 29th and 30th, DQ Herculis was observed remotely from Flarestar Observatory. The star was monitored through a 10" SCT utilising a Moravian G2-1600 CCD camera set at a sensor temperature of -15 degrees C. Exposures were of 120 Second duration taken through a clear filter. DQ Herculis (Nova Herculis 1934) was a nova that erupted in 1934 and is considered an important variable star in astrophysics. DQ Her an eclipsing binary, and is also classified as an intermediate polar. Due to the high orbital inclination of the DQ Her system, the star exhibits eclipses every 4.6hrs. One such eclipse was caught on the lightcurve. All data was sent to the AAVSO & VSNET for further analysis. |
Observations of PNV J20422233+2712111 [2017 Apr 22/23]
On 2017 April 13, H. Nishimura, Kakegawa, Shizuoka-ken, from Japan discovered a transient using Canon EOS 5D digital camera + 200-mm f/3.2 lens. This object was also independently discovered by T, Kojima (April. 13.743 UT, mag.= 10.5); Gunma-ken, Japan and by S. Kaneko (April 13.754 UT, mag.= 11.1). Online discussions on this new transient stated that this object seems to be a dwarf nova in outburst rather than a classical nova. The outburst amplitude was reported as being very large at 9 magnitudes from a probable source at the same location. The transient has been described as a likely UGWZ- subtype Cataclysmic Variable.
On April 22nd, Gianluca Masi reported that the source, designated as PNV J20422233+2712111 exhibited superhumps. On the same day, observations of the object were acquired from Flarestar Observatory and the CV variable star was monitored from 22:08 to 03:20 UT through a programmed session that acquired data automatically. Results indicate that the superhump amplitude increased from 0.1 (as reported by Masi) to 0.26 magnitude. Observations of this newly discovered variable star were sent to the AAVSO for further analysis. All images were acquired through a clear filter and had an exposure duration of 60 seconds.
On 2017 April 13, H. Nishimura, Kakegawa, Shizuoka-ken, from Japan discovered a transient using Canon EOS 5D digital camera + 200-mm f/3.2 lens. This object was also independently discovered by T, Kojima (April. 13.743 UT, mag.= 10.5); Gunma-ken, Japan and by S. Kaneko (April 13.754 UT, mag.= 11.1). Online discussions on this new transient stated that this object seems to be a dwarf nova in outburst rather than a classical nova. The outburst amplitude was reported as being very large at 9 magnitudes from a probable source at the same location. The transient has been described as a likely UGWZ- subtype Cataclysmic Variable.
On April 22nd, Gianluca Masi reported that the source, designated as PNV J20422233+2712111 exhibited superhumps. On the same day, observations of the object were acquired from Flarestar Observatory and the CV variable star was monitored from 22:08 to 03:20 UT through a programmed session that acquired data automatically. Results indicate that the superhump amplitude increased from 0.1 (as reported by Masi) to 0.26 magnitude. Observations of this newly discovered variable star were sent to the AAVSO for further analysis. All images were acquired through a clear filter and had an exposure duration of 60 seconds.
Outburst of OV Boo [2017 March 17]
The news came out that the WZ SGE-type dwarf nova OV Boötes has been seen in outburst recently. In consideration that its outbursts are far in between and is now in a bright state, the telescope was directed towards this interesting system. The lightcurve obtained shows that the object has exhibited prominent double-wave superhumps up to an amplitude of around 0.6 magnitude. OV Boo is expected to continue in a bright state but its outbursts are usually rather short with possible re-brightinings.
OV Has been observed through a clear filter from 19:50 up to 22:34 UT through a 0.25-m SCT telescope. Data points on the lightcurve were based on 30 second exposures through a total cadence of 38 seconds.
The news came out that the WZ SGE-type dwarf nova OV Boötes has been seen in outburst recently. In consideration that its outbursts are far in between and is now in a bright state, the telescope was directed towards this interesting system. The lightcurve obtained shows that the object has exhibited prominent double-wave superhumps up to an amplitude of around 0.6 magnitude. OV Boo is expected to continue in a bright state but its outbursts are usually rather short with possible re-brightinings.
OV Has been observed through a clear filter from 19:50 up to 22:34 UT through a 0.25-m SCT telescope. Data points on the lightcurve were based on 30 second exposures through a total cadence of 38 seconds.
Observation of EI UMa [ 2017 March 11]
The streak of bad weather continued, however during the intervening time, the rotational period of two asteroids were discovered. This does not mean that the observation of variable stars was diverted in favour to asteroids. Variable Stars will certainly remain on my observing menu. If fact, EI Ursa Majoris was observed on the night of March 11 from 18:07 to 00:45 UT. During this period, 235 observations were gathered through Clear-filtered images of 60 second duration with a resulting cadence of 68 seconds.
The lightcurve shows a marked decline in brightness from around magnitude 15.00 down to magnitude 15.3 with an interim flickering of around 0.1 magnitude. The gap in the middle was due to technical problems with the automated focusing routine that took some time to resolve before observations could continue. All observations were uploaded to AAVSO and CBA for further analysis.
The streak of bad weather continued, however during the intervening time, the rotational period of two asteroids were discovered. This does not mean that the observation of variable stars was diverted in favour to asteroids. Variable Stars will certainly remain on my observing menu. If fact, EI Ursa Majoris was observed on the night of March 11 from 18:07 to 00:45 UT. During this period, 235 observations were gathered through Clear-filtered images of 60 second duration with a resulting cadence of 68 seconds.
The lightcurve shows a marked decline in brightness from around magnitude 15.00 down to magnitude 15.3 with an interim flickering of around 0.1 magnitude. The gap in the middle was due to technical problems with the automated focusing routine that took some time to resolve before observations could continue. All observations were uploaded to AAVSO and CBA for further analysis.
A short observation session on YZ CNC [2017 JAN 23]
After a prolonged period of abstinence from observational work due to bad weather condition, the sky finally cleared up again for a brief time. In response to a call for observations, YZ Cancri was observed on January 23 from 19:18 to 23:00 UT. The session had to be terminated earlier than expected as cloud cover prevented further monitoring. Never the less, a usable set of observations were acquired through clear-filtered 60 second exposures.
Observations reveal that this SU UMa type variable was undergoing a normal outburst at an average magnitude of 12.85 in V-band. Further observations are anticipated weather permitting. Observations were sent to AAVSO and CBA for further analysis.
After a prolonged period of abstinence from observational work due to bad weather condition, the sky finally cleared up again for a brief time. In response to a call for observations, YZ Cancri was observed on January 23 from 19:18 to 23:00 UT. The session had to be terminated earlier than expected as cloud cover prevented further monitoring. Never the less, a usable set of observations were acquired through clear-filtered 60 second exposures.
Observations reveal that this SU UMa type variable was undergoing a normal outburst at an average magnitude of 12.85 in V-band. Further observations are anticipated weather permitting. Observations were sent to AAVSO and CBA for further analysis.
BZ CAM [2016 DEC, 21, 24, 27]
Attention was reverted to the nova-like variable BZ Cam that was as bright as a magnitude 13.0 star during some nights of observation. LC's show the characteristic flickering oscillation behaviour that is common amongst nova-like variables. Each data point represents a 60 second observation through a V-band filter. All observations were carried out through a 0.25-m SCT operating at F/6.3 and mounted on a NEQ6 Pro mount. Camera employed: Moravian G2-1600 CCD operating at -15C degrees. All observations were sent to the AAVSO and CBA for further analysis. First two lightcurves show the magnitude scale as difference in mags while the last lightcurves shows the actual brightness in V-Band. Note that JD range differs according to the duration of the session concerned. |
Paper: Lightcurve Analysis for Three Main-Belt Asteroids [Published 21 Dec 2016]
Following a peer review process, a scientific paper entitled ‘Lightcurve Analysis for Three Main-Belt Asteroids’ was accepted and published on the front page of Volume 44-1 of the Minor Planet Bulletin (MPB). The MPB is a quarterly peer reviewed open-access scientific journal that focuses on minor planets (asteroids). The above paper had the objective to acquire photometric observations of three main-belt asteroids that had no known synodic rotation periods (length of day). The asteroids under study were 1154 Astronomia (1927 CB), 3680 Sasha (1987 MY) and (6138) 1991 JH1. Differential photometry was employed to determine synodic rotation period through the acquisition of photometric data that enables the transformation of such data into lightcurves (graphs that illustrate brightness against time) that help to derive asteroid rotation periods. All observations were acquired at Flarestar Observatory (IAU/MPC Code: 171) that employed a 0.25-m f/6.3 Schmidt-Cassegrain telescope. 1154 Astronomia (1927 CB) was observed on 8 nights from 2016 May 5 to June 14. 347 photometric observations were used to find the synodic period of this asteroid that was derived as 18.1154 ± 0.0139 h with an amplitude (brightness) range of 0.39 ± 0.05 magnitudes. |
3680 Sasha (1987 MY) observed on four nights in March2016. A lightcurve made up of 329 data points showed that the asteroid’s synodic period is of 5.8145 ± 0.005 h with an amplitude of 0.30 ± 0.05 mag.
Discovered in 1991 6138 (1991 JH1) is an asteroid that is officially numbered as 6138 and is still waiting to be named. This main-belt minor planet was observed over a period of 3 nights ranging from 2016 March 27 to April 10th. 218 data points were acquired that formed the basis of the lightcurve. Lightcurve analysis (as for the above mentioned asteroids) were analysed through Fourier analysis to yield a derived synodic period of 5.4578 ± 0.006 h with amplitude of 0.30 ± 0.09 mag.
Discovered in 1991 6138 (1991 JH1) is an asteroid that is officially numbered as 6138 and is still waiting to be named. This main-belt minor planet was observed over a period of 3 nights ranging from 2016 March 27 to April 10th. 218 data points were acquired that formed the basis of the lightcurve. Lightcurve analysis (as for the above mentioned asteroids) were analysed through Fourier analysis to yield a derived synodic period of 5.4578 ± 0.006 h with amplitude of 0.30 ± 0.09 mag.
Observations of Blazar CTA 102 [4 December 2016]
Radio quasar CTA 102 (also historically known as 4C +11.69) has been reported to be currently active and is in a prolonged outburst activity at optical and gamma-ray energy bands. Visual (V) and Infra-red (Ic) observations of blazar CTA 102 were carried out from Flarestar on 4th December, 2016. Data aquired through a short session, that lasted from 17:17 UT to 19:43 UT shows that this quasar exhibited variation in brightness even on such short time scales. The lightcurves obtained were based on 90 second exposures through V and Ic bands under a maximun airmass of 1.451. All observations were obtained through a 0.25-m SCT telescope working at F/6.3. Images were obtained through a Moravian G2-1600 camera set at sensor temperature of -15 degrees C. |
Discovery of a Binary Star System in the Constellation of Libra from Malta [2016 Nov 19]
During the night of May 4/5th of 2016, time series photometry from my observatory at San Gwann was performed to determine the rotation period of asteroid 1154 Astronomia. Subsequent analysis of the acquired data indicated that a comparison star employed for aperture photometry during that night faded slightly in brightness. This indication suggested that this comparison star had to be discarded from the analysis of 1154 Astronomia and instead had to be replaced by a more stable star. A new comparison star was added while next to the discarded star, on my nightly star-chart (Figure 1), the note ‘var?’ was jotted down next to the alleged variable star. A run of clear nights enabled me to determine the rotation period of 1154 Astronomia. A paper containing the results of two other asteroids was submitted to the Minor Planet Bulletin (MPB). The MPB is a journal devoted to dissemination of research conducted through asteroid photometry. Following a peer review process, the paper was accepted for publication by the review committee and is due to appear in the next issue of MBP. On October 30th, I recalled the event about the possible variable star and after consultation with my journal, the photometry report of the night was singled out to have closer look at the data. As a start, the images of that night were analysed through the photometry analysis software - MPO Canopus that comprise an algorithm for detecting variable stars. The resultant RMS diagram picked up the star as a possible variable star candidate. Having acquired the exact coordinates of this star, the VSX database which is one of the most extensive catalogues of variable stars was consulted. A search around the location of this star yielded no known variable stars. Other professional catalogues such as GCVS, SWASP, NSVS, APASS, CRTS, ASAS-3, revealed no new results. Although the latter four had records of this star on different nights without identifying it as such, the results from the CRTS (Catalina Real-Time Transient Survey) were the most rational. However, most of the data acquired consisted of 3 data points per night at most. This has most likely hampered the automated detection routine of the survey and probably failed to hail it as a variable star as the periods derived were contradictory. The acquisition of additional survey data prompted me to carry out a thorough analysis of my data. The resultant lightcurve of this analysis is depicted in Figure 3 shows that the gradual decline was indeed real. An exchange of emails with AAVSO’s consultant Sebastian Otero, my data and all survey data were merged into one dataset to derive amore tangible periodicity solution. From the phenomenological characteristics of the light curve, it was possible to determine not only the period at P=0.441456 d (10.59744 hrs) but also its class. It turns out that this variable is an EW/RS type system. EW systems (also known as W UMa type variable stars) are eclipsing binaries with components in near contact, where their mutual gravity has distorted the stars into ellipsoids. RS systems are referred to as a class of variable stars named after the first variable star of this class – RS Canum Venaticorum (or RS CVn for short). RS CVn stars exhibit large stellar spots (like sunspots) but unlike the Sun, these spots can cover half of the star’s surface. Due to our line of sight from Earth, these stars continuously eclipse each other. However the resultant lightcurve of this EW/RS system does not replicate exactly over time and amplitude as star-spots facing our direction on one member swerve the oscillation of the lightcurve from the norm. Hence, the resultant folded (phased) lightcurve obtained contains considerable scatter due to the presence of star-spots that also have their own activity period such as the 11-year sunspot cycle on the Sun. |
The location of this newly found variable star is located in the Constellation of Libra (2.2° West of the midpoint between α and β Librae). Hence, it is not visible during the winter months. Further observations of this system are anticipated to take place during the spring period where colour photometry will reveal further details about this interesting star system. Below please find the details of this variable star that has been assigned the AAVSO Unique Identifier – AUID 000-BMC-748.
Star: GSC 05586-00371 Other IDs: UCAC4 388-064982 Position: RA 14h 55’ 43.26” ; DECL. -12° 30’ 28.3” Magnitude Range: 13.4 -13.8v VSX Link: https://www.aavso.org/vsx/index.php?view=detail.top&oid=475853 A special thanks is directed towards Sebastian Otero for his invaluable guidance and help and to the AAVSO for maintaining the VSX Database. The CRTS survey is supported by the U.S.~National Science Foundation under grants AST-0909182 and AST-1313422. [Drake, A.J. et al. First Results from the Catalina Real-time Transient Survey, 2009, ApJ, 696, 870] |
Observations of a Microlensing event – Gaia16aye [Updated: 2016, Nov 19]
The astronomical satellite GAIA has triggered an alert (designated Gaia16aye) announcing a flare event (surge in brightness) that has occurred on a normal star. As the flare signature observed was considered as uncommon occurrence on the star observed, the event was followed up by a number of observatories under OPTICON (Optical Infrared Co-ordination Network for astronomy). Observations through multiple bands since August showed achromatic changes in the star’s brightness that was consistent with a microlensing event of a distant M-type star. The red star (at mag 14.9mv and colour of B-V=1.6) gradually brightened up to a rate of 0.6 magnitude per day. The lightcurve shape and spectra obtained are similar to another microlensing event that occurred on 31st October,2006. The complex geometry of the lens has created multiple brightening events that were interpreted as caustic crossings. Astronomers are predicting more brightness variations in the coming days following another set of events in the coming weeks. They also requested data from amateur astronomers to enable them to gain continuous monitoring of this unusual event. The GAIA team has issued a call for observations to the American Association of Variable Star Observers (AAVSO) to monitor this event immediately and continuing through the end of October in order to establish the physical parameters of the gravitational lens. Observations of GAIA16aye were acquired through the Infra-red band (Ic) on a number of nights from Flarestar Observatory (Malta) and submitted to the AAVSO for onwards processing. The lightcurve shows a gradual decline consistent with the observations produced by OPTICON observatories. |
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Weather permitting, this star will be monitored through the coming weeks as astronomers are predicting a abrupt increase in brightness in the coming days.
The Light curve at the end of this section illustrates the behaviour of this microlensing event. Dark spots represent data from Gaia the GAIA survey. Additional data was supported by data from OPTICON ground-based data with each colour indicates a different observatory. The solid black line depicts the latest microlensing model as computed by Przemek Mróz. This updated lighturve is reproduced from http://www.astrouw.edu.pl/~pmroz/gaia16aye/model2.png
The Light curve at the end of this section illustrates the behaviour of this microlensing event. Dark spots represent data from Gaia the GAIA survey. Additional data was supported by data from OPTICON ground-based data with each colour indicates a different observatory. The solid black line depicts the latest microlensing model as computed by Przemek Mróz. This updated lighturve is reproduced from http://www.astrouw.edu.pl/~pmroz/gaia16aye/model2.png
Observation of the Binary Star System - V0442 CAM [2016 OCT 8th]
The binary star system was observed in order to determine the time of minimum during the eclipse. This star system was monitored from 22:27 UT to 03:28 UT through 120 second exposures. Time series imaging through a C filter revealed a brightness decrease from 13.8 to 14.2 mag (based on V) during the eclipse duration. All images were taken through a 0.25-m SCT telescope and a Moravian CCD camera operating at a temperature of -15C. Data was also submitted to AAVSO for onward processing. |
Observation of V0515 Andromeda [2016 September 21/22]
Secondary target for the night included the star V515 And. List as a DQ Herculis type, This magnetic cataclysmic variables generates a magnetic field but is weaker than the field associated with AM Herculis stars and is not strong enough to synchronize the orbits of the rotating white dwarf with the orbital period of the system. DQ's are also known as Intermediate Polars (IP). Data was submitted to AAVSO for onwards processing and analysis. This star system was observed from 23:36 to 03:16 UT through 120 second exposures through a C-Filter. This star was observed through a 0.25-m SCT telescope operating at F/6.3 with a resultant pixel scale of 0.99 arc seconds. A Moravian G2-1600 CCD camera was used to acquire the data. |
Observation of two asteroid occultation events on September 1st, 2016
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Observation Sessions on V SGE [2016 AUG, 09; 14] Discovered in 1902, V SGE is classified as a CBSS/V+E? type variable. This nova-like cataclysmic star exhibits variation in depth of eclipses from 0.6m to 1.3m. The mean brightness outside eclipses varies. It is also reported that flares with amplitudes up to 3m and small light variations with a time scale of minutes, dozens of minutes and a few days are also occasionally exhibited. Two sessions were conducted on this interesting variable star system on August 9 & 14. This star system was monitored through V (visual) and Ic (infrared) bands through 120 second exposures. The session of the 14th was carried out through V band only. The lightcurves show a continuous eclipse of the system through RAW plots produced by MPO Canopus. All images were acquired through a 10 inch SCT telescope working at F/6.3. A G2-1600 Moravian CCD camera was used at a set temperature of -15C (at 23 degrees C ambient). |
Discovery of a Variable Star in the Constellation of Aquila [July, 2016]
A previously unknown variable star was discovered from Flarestar Observatory during the month of July. The star catalogued as UCAC4 472-112478 was discovered to be a W Ursa Majoris (W UMa) type eclipsing binary. Prior to this study, the star was not known to be a star that varies in brightness. The data acquired indicates that this binary star system has an orbital period of 0.4145 +/- 0.0007 days with an amplitude (variation in brightness) of 0.43 mag. This star systemhas a total maximum brightness of 15.57 magnitude. This brightness reading implies that this star is around 6,300 times fainter than the faintest star visible with the unaided eye. Following a notification to the American Association of Variable Star Observers (AAVSO), the data was vetted by the AAVSO and has now been officially designated as AUID 000-BLY-673. The variable star is located around 5.2° due south of the bright star Altair (α AQL) in the constellation of Aquila at RA 20h 03’ 30.10” DECL +04° 12’ 30.6” (2000) This variable star system was discovered inadvertently after a variable star search was conducted at the above mentioned coordinates. Images of this area were originally acquired to investigate the rotation period of a main-belt asteroid. However, the starfield density on the image prompted me to submit the images through a routine that searches for variable stars. The search yielded a candidate star that showed some variability in brightness during a single night. Searches among professional databases did not reveal any known variable in the vicinity of the object. This negative result called for a dedicated monitoring program for a number of nights. A call for support was issued to astrophotographer Winston Grech that kindly accepted my request to submit images of the area concerned. Inadvertently, technical difficulties were encountered as astrophotographers rarely follow scientific protocol. However, Winston endorsed all my suggestions and modified his procedures at the telescope that permitted the acquisition of scientifically valuable data. Two nights out of the eighth acquired (Session #152 & #160) were supplied by Winston Grech where his observations assisted towards the refinement of the derived orbital period. Up to the 4th night of monitoring, the period and the type of the variable star concerned was yet unknown. At the time, all that could be derived was the amplitude of the variability observed. A following all-night session was crucial to yield a clue on the actual period. The use of Fourier analysis algorithm was instrumental to confirm a definite period as possible period aliases were eliminated. Analysis of the resultant lightcurve suggested that the variable star involved is a ‘W UMa’ type variable star that is thought to be a contact binary system. It is thought that these two stars previously were a detached (wide) binary system that subsequently closed in together as a result of orbital decay by angular momentum loss. Further data will be gathered in the coming months to yield further information on the system’s properties. Special thanks are directed to Winston Grech for his contribution to this collaborative project. |
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A night monitoring DQ Herculis [2016 July 05]
DQ Herculis (formerly Nova Herculis 1934) was a bright nova that erupted in December 1934. At its peak it reached magnitude 1.5 but faded beyond naked eye visibility after a few months. DQ Her is also an eclipsing binary and has been classified as an intermediate polar. Polars are CV stars where the white dwarf has a strong magnetic field that succumbs the accretion stream from the secondary star surface to the magnetic poles of the white dwarf. DQ Herculis' white dwarf rotation along with radiation along the magnetic fields causes variability at a period of 71 seconds (not shown in the LC here as integrations of 90 seconds were used). DQ is also a binary star system that goes into eclipse every 4.646 hours. The LC shows such eclipse that drops down to magnitude 16.5 mv. The session on DQ was acquired through a 10 inch SCT working at f/6.3. CCD employed is a Moravian G2-1600 model working at -15C (ambient temp stood at 22 degrees C). Over 240 C-Filtered images of 90 second integrations make up the lightcurve shown here. |
Observation of the enigmatic Star - KIC 08462852 (aka Tabby's Star) [2016 June 28]
This star is an unusual target as the nature of its variability is not really known. A drammatic fading was observed by the KIC telescope that showed aperiodic fading events.True cause is unknown but explanations range from asteroid belt collisions that blocked the starlight coming from the star; dust clouds orbiting within the Hill spheres in an asteroid-belt type setting to fragments from the remnants of a comet (and even to alien mega-structures!). Currently the variations have subsided but many astronomers are keeping a close tab on this star as it is not known when such fadings will really happen again. I felt that target is a must (even for one night). This star has also being monitored by the AAVSO. A short observation session was dedicated in order to acquire photometric observations through V and Ic (infra-red) bands. Session lasted from 20:03 to 23:35 UT through 60 second integrations in alternating mode for both filters. The resultant LC shows that this star is brighter in the Infra red than in V due to its spectral class F3IV/V that leans more towards the red than to the visual (550nm) end of the spectrum. Observations were reported to the AAVSO. LC was derived from AAVSO Lightcurve Generator. |
Observation Session: V0795 Herculis [2016 June 26, 29]
A short session on the interesting variable star system - V0795 Her was conducted between 19:13 and 21:26 UT on June 26. This star system was monitored through V (visual) and Ic (infra-red) bands through 60 seconds exposures. Due to flickering nature of this variable, the resultant lightcurves from V and Ic do not match well as in between the exposures, the star system changed in brightness. The upper lightcurve depicts the variation in light of this star system through V-Band while the figure underneath shows variations in infra-red (Ic - Band). Lightcurves have been acquired through AAVSO's V-PHOT and the combined Lightcurve was acquired through the AAVSO's Lightcurve Generator program. All images were acquired through a 10 inch SCT telescope working at F/6.3. A G2-1600 Moravian CCD camera was used at a set temperature of -15C (24 degrees C ambient). Another session, this time through a C-filter was acquired on June 29. Session lasted from 19:45 to 00:33 UT. Integrations were of 60 second duration that were taken under a maximum airmass of 1.224. Sky had a sky brightness of 18.68 magnitudes per square arc seconds that rate as moderate under local conditions. As this session, images were taken in succession through one filter, the temporal resolution of the LC is higher than those shown here for V and Ic bands. |
MPB Paper: Rotation Period Determinations for 1166 Sakuntala and 3958 Komendantov
Following a peer review process, a scientific paper entitled ‘Rotation Period Determinations for 1166 SAKUNTALA and 3958 KOMENDANTOV’ was accepted and recently published in Volume 43-3 of the Minor Planet Bulletin. This study had the objective to acquire photometric observations of two asteroids to update the synodic rotation period of 1166 Sakuntala and to determine the synodic rotational period of 3958 Komendantov. Differential photometry was employed to determine the lightcurves for these asteroids and derive their rotation periods. All observations were acquired at Flarestar Observatory (MPC Code: 171) through a 0.25- m f/6.3 Schmidt-Cassegrain telescope. During June 2015, photometric observations of 1166 Sakuntala were acquired over 5 nights during which the phase angle ranged from 6.3° to 17.3° before opposition. Asteroid Sakuntala was found to have a synodic rotation period of 6.2915 ± 0.002 h and lightcurve amplitude of 0.32 magnitudes. This coincides well with the period previously published by Malcolm (2001) that determined the period as 6.30 h. Starting on 2015 September 12, photometric observations of 3958 Komendantov were also acquired over five nights were the phase angle ranged from 6.9° to 2.5° before opposition. The derived lightcurve was based on 985 photometric observations. Prior to thus study, the rotation period of this asteroid was yet unknown. 3958 Komendantov was discovered to have a synodic rotation period of 11.2947 ± 0.0023 h with amplitude of 0.27 magnitudes. |
Three observing sessions on 1SWASP J162117.36+441254.2 [2016 June 7, 8 & 10]
Three observing sessions on the variable star 1SWASP J162117.36+441254.2 (aka 2MASS J16211735+4412541) were conducted from Flarestar Observatory. This star system was observed as lately it has gone through an outburst that brightened up the star system. Photometric measurements were based on images that had a duration of 60 seconds for the first two sessions with 120 second exposures for the 3rd session (JD 2457550). All observations were taken through a C-filter. Lightcurves shown were acquired through AAVSO's VPHOT program. This star was reported in outburst on 2016 June 03.45 UT by CRTS and was classified as a transient event at a brightness of V_CSS=13.3. It was reported that this system has an average magnitude of around 15.0 mv with an amplitude of half a magnitude.This system was previously identified by Palaversa et al. (2013) as a contact eclipsing binary of WUMa type by Palaversa et al. with a combined period of P=0.207852 days. This short period places 1SWASP J162117.36+441254.2 as an ultra-short period binary system. Results of phased lightcurves by Drake et al. (2014b) suggest that this system is rather more ellipsoidal (WD+MS) than a WUMa system (Ref: http://www.astronomerstelegram.org/read=9112) |
Short Observing session on MV Lyrae [2016 June 02]
A short observing session with a duration of 54 minutes was carried out on the night of 2/3 June. This observation opportunity was taken in between other observing programs that are currently being undertaken at Flarestar. Despite the short period of observation, MV LYR has continued with its characteristic flickering activity at least during this observing period. but at a The amplitude has somewhat decreased but the rate of flickering, as well as the average magnitude as compared to the previous session has has been maintained. The average magnitude between the two sessions differed by just 0.008 of a magnitude. 45 images of MV LYR were acquired through 60 second integrations that had an interval of 6 seconds (download time). All images were taken through a C-filter at a set CCD Camera temperature of -25° C (-43° C below ambient T.) Observation of MV Lyrae [2016 May 22]
Through an all-night session, the CV star MV LYR was observed remotely on May 22. The target situated in the constellation of Lyrae was observed through a maximum airmass of 2.7 that decreased to nearly 1 airmass by the end of the session. All observations were acquired through a 0.25-m SCT telescope working at its native focal length of 1650mm (f/6.3). All images had an exposure of 60 seconds each that were taken through a C-filter. Data has been processed through MPO Canopus and AAVSO's VPHOT program. It should be noted that MPO Canopus utilised HJD (Heliocentric) as a reference for time while AAVSO's VPHOT has adopted JD without any corrections. The lightcurve of MV LYR shows the flickering-like behaviour that is commonly exhibited by nova-like variable stars. In fact, MV is classified as a NV type variable star and is also classified as a VY Scl subtype variable. The top lightcurve has been derived through MPO Canopus that shows well the amplitude of the star concerned. However in this case, VPHOT shows the flickering behaviour better when data points are joined together through lines. |
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Observation of the CV Star - ASASSN-16dt [2016 April 26]
ASASSN-16dt was observed from Flarestar Observatory on 2016 April 26 from 18:52 to 23:40 UT through a 10 inch SCT operating at f/6.3. During the observing session, over two hundred 60-second integrations were acquired through a C-filter. Using MPO Canopus, the period derived through this session yielded a period of 0.0652 ± 0.0005 d that is consistent with what other observers are reporting. The amplitude of the object at the time of observation was 0.13 mag. |
Observation of the Cataclysmic Variable Star - IR GEM [2016 March 27; 28; 30]
IR GEM was observed from 18:33 to 21:09 UT on 2016 March 27; 18:14-20:44 UT on March 28 and 18:27-20:05 UT on March 30th. The lightcurves were based on 60 second exposures through a C -filter. Telescope employed was a 0.25-m SCT working at f/6.3. All images were acquired through a Moravian G2-1600 CCD camera set at sensor temperature of -25 C. IR GEM is classified as a UGSU type variable that can exhibit superhumps during outbursts as shown on the lightcurve. AAVSO's VSX reveals that this star has a periodicity of 0.0684 d and has a magnitude range of 11.2 - 18.7 in V-band. Lightcurves derived through AAVSO's V-Phot online program. |
Observation of the nova-like eclipsing binary - BH LYN
This cataclysmic variable star was observed remotely on 2016 February 19, 20, 25, 26 and 29 usually from dusk up to around 02:45 UT when the target hits the 30 degree altitude at 2 atmospheres. All observations were acquired through a 0.25-m SCT telescope working at its native F/6.3. Exposures were all of 120 seconds each through a C -filter. All data has been processed through MPO Canopus. BH Lynx has a listed period of 0.155875629 d (3.7410151 h) and my observations correlate well with this period. This implies that this binary systems' orbital period is rather constant as not much deviation has been observed from the published period. Nevertheless, a subtle period shift could not be excluded at this early stage and with the limited amount of information available through four sessions. The phased lightcurve shows the folded lightcurves of the five sessions that were overlapped to determine the period mentioned here. The listed magnitude range of this star varies between 13.7 - 16.3 in Blue light. My observations depict an approximate magnitude range between 15.0 down to 16.6 in V-band with a computed period of 0.15587 ± 0.00001 d. |
Discovery of two Binary Star systems in the Constellation of Perseus
These variable stars were discovered thanks to a survey that was carried out over a particular area in the sky located at 2.8 degrees west of the Double Cluster in Perseus. The variable stars were discovered on December 6th, 2015. A number of nights were dedicated to divulge the type and periodicity of these stars. Exposures were first set at 90 seconds, however 4-minute exposures were then employed to improve the signal to noise ratio. Searches conducted on many professional surveys yielded no positive results and this prompted me to submit these candidate variables to the AAVSO VSX (Variable Star database). After a period of review, these stars were acknowledged as newly discovered binary star systems. Data from the additional sessions uncovered a pattern that showed the class of variable stars under study. The periodicity was determined thanks to two sessions on each star that showed the binary system undergoing an eclipse. The lightcurves of both stars showed that they are Algol-type systems. Here are the details of the newly discovered variable stars: UCAC4 735-019611 (AUID 000-BLW-283) RA: 01h 56' 10.3231" Decl. +56 57' 56.125" Magnitude 16.1 (Range 0.55) Period= 2.1271 d ± 0.001 d Eclipse Duration: 9% Epoch JD: 2457363.377841 UCAC4 736-020428 (AUID 000-BLW-284) RA: 01h 57' 54.600" Decl. +57 08' 31.832" Magnitude 15.1 (Range 0.5) Period= 1.2295 d ± 0.0014 d Eclipse Duration: 12% Epoch JD: 2457380.464017 Additional observations are planned to gather more data about the systems’ properties. |
Observation of RZ Leonis system - 5th February 2016
RZ Leonis has just undergone its 8th recorded outburst since its discovery in 1918. Last night, part of my telescope time was dedicated to the RZ Leonis system. C-filtered photometric data based on 60-second exposures revealed post-outburst superhumps. On February 5th 2016, RZ Leonis was monitored remotely from 22:07 to 04:45 UT. The resultant lightcurve was based on 311 observations. Zero point stands at magnitude around 13.85 mv. Through these observations, the superhump period was derived as 0.0777 d ± 0.0013 d. The phased lightcurve shows a folded lightcurve to characterize the shape of the superhump cycles. All observations were acquired through a 10 inch Schmidt-Cassegrain telescope coupled to a Moravian G2-1600 CCD Camera set at a sensor temperature of -25°C. Observation of RZ Leonis system - 8th February 2016
An additional night on the star system RZ Leo was carried out on 8thFebruary. RZ Leonis was observed from 20:36 to 04:45 UT. 332 images of 60-second exposure were acquired through a 0.25-m SCT telescope.All images were taken through a C-filter. The resultant light curve for the night shows the characteristic superhumps however, their shape differed slightly as the latest observations (in grey) show a more pronounced maxima than to those acquired on February 5th. Since then, their amplitude has changed slightly from 0.24 to 0.22 magnitudes. Fourier analysis was employed to combine the light curve data of February 5th (Period=0.777 ± 0.0013 d) with data from the latest session (P=0.0780 ± 0.0011 d) to yield a more refined of period of 0.0782 ± 0.0002 days. |
Observation session on the variable star 1RXSJ064434.5+334451
This cataclysmic variable was observed remotely on January 11 from 00:30 UT up to 03:30 UT. 157 data points on the lightcurve are made up of 60 second integrations through a 0.25-m SCT telescope working at F/6.3. The LC shows well the 1.2 magnitude deep eclipse that reoccurs every 0.26937447 days. This periodicity is not static as period shifting has been observed through O-C diagrams. |
Rotation Period Determination for Asteroid 9773 (1993 MG1)
Observed in conjunction with Vladimir Benishek from the Belgrade Astronomical Observatory Serbia, Photometric observations of the Mars-crossing asteroid (9773) 1993 MG1 were conducted over seven nights in 2015 July from Malta and Serbia. A synodic rotation period of 2.74595 ± 0.00006 h and lightcurve amplitude of 0.29 ± 0.02 mag were determined from the data. Details from this observing campaign has been published in the Minor Planet Bulletin journal and can be found on the NASA Abstract Service server. |
1RXS J064434.5+334451 [Dec 06, 2015]
This CV variable was observed from 23:38 to 03:57 UT through remote operation . 60 second integrations were used to acquire the light curve. During the session, two cloud occurrences obscured the viewing of this interesting star system. Fortunately, clouds did not interfere with the viewing of the eclipse itself. All observations were taken through a C filter under a 19.00 magnitude per arc seconds sky. |
BZ CAM [Nov, 3, 11, 16]
Turned the attention to the nova-like variable BZ Cam that was as bright as a magnitude 12.8 star during the observation. The LC's show the flickering oscillation behaviour that is common amongst nova-like variables. Each data point represents a 60 second observation through a V-band filter. Sessions lasted around 3, 8 and 9 hours respectively. All observations were carried out through a 0.25-m SCT operating at F/6.3 and mounted on a NEQ6 Pro mount. Camera employed: Moravian G2-1600 CCD operating at -15C degrees. |
V592 CAS [Sept 26, 27 & Oct 5, 8]
Observed this bright nova-like variable that is currently as bright as a magnitude 12.7 star. These observations were meant to show the flickering oscillation that dominates the variability of this star. For the session of the 26th, 90 second exposures were utilised but for the subsequent sessions a shorter exposure was employed as to show better the flickering through enhanced temporal resolution. The LC beneath the October 5th entry shows the same session through strait line interpolation between data points. All observations were taken through an Astrodon V-band photometric filter. |
ASASSN-15po [Sept 11, 16, 17, 22]
This newly discovered variable was observed for a number of nights. Period is not very conspicuous, however further analysis are extected to reveal the period quite well. This star was observed at the initial stages after an outburst and thus the superhumps were of small amplitude that do not show so well at this stage. Through time, the amplitude is expected to increase that will divulge better the superhump oscillation. All observations were reported to the AAVSO and CBA for onwards anaysis. |
LQ PEG - [Aug 31; Sept 1, 2, 4, 11]
Four sessions were dedicated to observe the nova-like star, SU UMa type star - LQ Pegasi. During the sessions, superhumps were observed that had an average 3 hour periodicity. Amplitude range varied around 0.25 to 0.3 of a magnitude during the monitoring period. Observations were acquired through a 10 inch Schmidt-Cassegrain telescope coupled to a Moravian G2-1600 CCD Camera set to sensor temperature of -15°C. At the time of observation, the average magnitude of this system stood around 14.8 magnitude. CCD exposures ranged from 90 (S1) to 120 seconds (S2,S3,S4). Session 3 (Sept 2) was interrupted prematurely as clouds obscured the sky. All observations were reported to the CBA and the AAVSO. |
2015 Aug 26 - LS PEG - Session 5
This session that commenced at 18:56 UT and lasted up to 02:22 UT yielded 376 observations of this interesting and quite active variable. The near 20 minute quasi periodic oscillation could still be discerned amongst the variation in brightness. All exposures had a duration of 60 seconds. Observations were acquired under a bright sky as the gibbous moon (88% illumination) was above the horizon up to 01:40 UT. The night sky brightness was recorded at +18.15 mag/arcsec^2 at 20:28 UT. All observations of LS Pegasi were reported to the AAVSO and the CBA. |
2015 Aug 23 - LS PEG - Session 3
Shorter integrations of 60 seconds were used to throughout this session. This produced higher temporal resolution that enhanced the quality of the data. Session started from 20:39 UT and was concluded at 03:15 UT. A noticeable decline in brightness could be discerned during the end of the session. Such occurrences might reveal periodicity characteristics that could be of help to define the period of this system. 344 images were acquired during this session. |
2015 Aug 22 - LS PEG- Session 2
Another all night session on this interesting Cataclysmic Variable. This intermediate polar star was observed from 19:20 UT to 03:10 UT. Data is based on 90 second integrations and all were taken through a C filter. By the end of the session, 283 images were acquired that produced the light curve shown here. Upper lightcurve shows the raw plot through MPO Canopus while the lower graph depicts the LC as derived through Excel. Data for the latter was extracted from the data output generated through MPO Canopus. |
2015 Aug 20 - LS PEG - Session 1
First session on LS Pegasi proved to be quite interesting. This NL/VY type variable varies in brightness from 11.5 down to magnitude 14.3 in V band. During this seven and a half hour session, 199 observations were obtained. All images had a duration of 120 seconds and all were exposed through a C filter. During this session, this star had a mean magnitude of around 12.3 V , however the amplitude ranged around half a magnitude. When the LC was displayed for the first time only noise could be discerned, however further analysis revealed a different picture. A kind of semi-regular oscillation could be divulged when data points were connected. For reference, the two lightcurves depicted here have different time references as the above LC was based on HJD while the other LC displayed a non-corrected time reference. |
2015 Aug 13 - V1315 AQL
133 images were acquired for V1315 AQL. The two minute exposure regime was maintained. All images were taken through a C filter. This night produced very good seeing conditions at 2 arc seconds which is very good for my site at near sea level. Sky brightness was slightly better than the previous session conducted on August 9. Session covers a period from 19:15 UT to 00:16 UT. All data for V1315 AQL was reported to AAVSO and CBA for further analysis. |
2015 AUG 9 - V1315 AQL
An all nighter on V1315 AQL for an extended mini-campaign on this variable. Eclipses amplitude remained consistent. Again, two eclipse events were recorded. Session covered a period from 19:02 UT up to 01:30 UT. Exposures were of 2 minutes each. Light curve consists of 178 data points. Sky brightness was recorded at 18.68 mag/arcsec ^2 at 19:41 UT. |
2015 AUG 5 - V1315 AQL
Second session on this star was subjected to the mercy of passing clouds that produced some gaps in the data. The first eclipse was clouded out as a small cloud decided to park itself on the filed to spoil the fun. At least, second eclipse was covered well. Session lasted from 19:10 UT up to 01:30 UT. All images were of two minute duration through a C filter. The 65% illuminated moon was above the horizon during the first part of the session. |
2015 August 4 - V1315 AQL
An all-night session on this Cataclysmic Variable provided good harvest. I was dumbstruck by the range of magnitude drop in a very short time when the CV had gone in eclipse. Going down by around 1.8 magnitudes in a span of less than 0.02 of a day (less than 30 minutes) is incredible. Session lasted from 19:10 UT to 01:28 UT through remote acquisition. Imaging was terminated at 01:28 UT as the star reached an airmass close to two atmospheres (+/- 30 degrees above the horizon). Images were of 120 second duration through a C filter. |
2015 July 31 - V SGE Observed this CBSS-type variable that is made up of a close binary system. It is sustained that Super soft X-rays could be produced by this system due to high luminosity close binary interaction and by continuous nuclear burning on the surface of an accreting white dwarf (WD). Observations carried out on the 31st reveal an eclipse of at least 0.4 of a magnitude. Data from other sources reveal a period of 0.514195 of a day. Each point in the lightcurve represents a V-band image of 120 second duration. Data analysis was performed through MPO Canopus. Interestingly, these observations were carried out on a night of a full moon! |
2015 July 24 - V1006 CYG Observations of the cataclysmic variable - V1006 Cyg were performed during the night of 24 July 2014. This SU UMa type variable experienced a re brightening lately. However, my observations caught this variable in decline with a slight upward trend before continuing to fade during the time of observation. All images were of 180 second exposure taken under a +19.01 mag/arcsec^2 sky. |
2015 July 21 - HO DEL
Cataclysmic variables are made up of star systems that have two components – a white dwarf primary and a red dwarf secondary. The orbital distance between these two stars may be so close that it is possible that the star system can fit inside the Sun. The short distance between the two components permits mass transfer from the secondary towards the primary star via a Roche Lobe overflow. Gravitational momentum does not permit material to fall directly onto the white dwarf and hence an accretion disc is formed around it. Mass interaction within the environs of the accretion disc can brighten the disk, enough to become the brightest part of the system. The photometry of super-outbursts reveals a peculiarity, modulation in the form of a hump appearing at super-outburst maximum. The periodicity of super-humps occur at a few percent longer than the orbital period. It is thought that these are due to tidal instabilities caused by the influence of the gravitational field of the secondary on the accretion disc. The raw plot shows the observations carried out on 22nd July when HO Delphini was in super outburst. The periodicity of super-humps is clearly visible in the lightcurve. Observations were carried out through three minute exposure images acquired through a 10 inch Schmidt-Cassegrain telescope. |
2015 July 1 - UX UMA
This interesting variable was observed for 2 hours 20 minutes through 120 second integrations. The observations were subjected to the Kwee and van Woerden algorithm to determine the Time of Minimum (ToM). Results from the observations obtained on this night reveal that ToM occurred on JD 2457205.36420 +/- 0.00017. This implies that the eclipse ToM occurred 26 seconds late from the predicted minimum. During the observation period, the star faded and brightened from magnitude 13.2V to 14.5V during the eclipse. More information on this interesting system can be found here on the AAVSO website. |
2015 June 28 - WZ CEP
Photometric work on binary stars is not severely affected by bright moonlight. As weather conditions were good enough, a session to observe WZ Cep was carried out under a bright moon. Session commenced at 21:09 UT and was concluded at 00:03 UT. through 120 second integrations. Eighty three 120-second exposures for the basis of this lightcurve (LC). The LC shows a primary eclipse of this system through a V-band filter. The predicted Time of Minimum was predicted to occur at 22:18 UT at JD 2457202.42974. Observations were analysed through the Kwee and van Woerden algorithm and results show that the observed Time of Minimum occurred on JD 2457202.42470 +/- 0.00008 d. This implies a period shift of (minus) - 6 minutes 25 seconds from the predicted time. |
2015 June 21 - Asteroid 1166 Sakuntala Engaged in a solo campaign to update the rotation period of 1166 Sakuntala. As this is the first asteroidal campaign after some considerable time, this target was selected due to its relatively bright apparition as it was set to brighten as a magnitude 12 star. This 24 km asteroid was discovered on 27 June 1930 by Parchomenko. The previous published rotation rate of this asteroid was recorded as 6.3 hours and the initial session confirmed that it is likely that the actual period is quite near that of the published period. However, this could only be ascertained through more data. 2015 June 26 - Session 2
Obtained an all night session on this asteroid. Data looks good and this session confirms that indeed the rotation period is near the 6.3 hour period. However, some aliases from the Fourier analysis by MPO-Canopus software suggested other possible periods of around 6.28h, 6.45h and 6.63h and this calls for further observations. The lightcurve produced on June 26 shows a typical lightcurve of an asteroid. Further data is set to be obtained at the earliest opportunity in the next July dark window (when the bright moon is out of the way). ADDENDUM: After three further nights of observation on this asteroid. The period was established with considerable certainty. Results will be sent to the Minor Planet Bulletin for official publication. |
2015 June 22 & 23 - V404 CYG
V404 Cygni is a binary system that is made up of a normal star orbiting a black hole. This system was observed in the V band through a 10 inch Schmidt-Cassegrain on two occasions. On the night of 22 June, this system was monitored for around three hours. The light intensity of this star varied to over 1.3 magnitudes in brightness during the time of observation (see lightcurve - entitled 20150622). The variation recorded is consistent with reports that documented high irregular variations at very short time scales. One June 23, this star was monitored for a period of around an hour. Further monitoring was not possible as the session was interrupted by the presence of low clouds that clouded up the sky. The lightcurve of this session (20150623) shows that the oscillations of the light variation were not as high as that of the previous session, however the irregular behaviour persisted. Further investigation revealed that the observed variability during the time of observation occurred when the star was less active as reports issued some time later documented oscillations with high amplitude that continued to persist later on. Such a ‘hyper-dynamic’ variable star event is not a common occurrence. The two minute exposures that formed the basis of the lightcurves represent an average of the total light output that occurred during the 2 minute exposures. Professionals have reported flickering events even at 2 second integrations! All observations were reported to the AAVSO. Addendum: 2015 June 27 - V404 CYG Observed V404 Cygni system but the brightness has declined drastically since the last session. The star was observed through 3 minute exposures to compensate the reduced brightness. The observed oscillations continued but at a lesser amplitude. During this session, the 80% lit moon was above the horizon. It is not known whether the total flux from the system will increase to the brightness observed on the 22nd and 23rd. From reports published elsewhere it looks like the total brightness is set to continue to decline. All observations of V404 CYG were carried out through V band. The duration of this session was much less than anticipated as clouds rolled in that brought the session to an end. The lightcurves of V404 were derived from data submitted to the AAVSO VPHOT software. |
2015 June 10 - V1036 HER
Nights with good seeing are not ones to be missed. Hence, a good binary target for the night was chosen. The binary star system V1036 Her was subject to an observing run on June 10th. This system situated at RA 16 55 51.90 DECL +24 53 36.1, shines as a 11.6 magnitude star that dims to magnitude 12.1 in eclipse. This EW-type variable star system has a period of 0.39165 of a day. The lightcurve extracted from observations on this night shows that the system was in a fading phase when observations started. Observations ended some time after mid eclipse but this was enough to derive a good Time of Minimum (ToM). ToM's are useful to derive the Observed minus Calculated (O-C) time that can show whether a period shift occurred. All images were of 1 minute duration and were taken through a Meade 10 inch Schmidt-Cassegrain telescope. CCD Camera employed: Moravian G2-1600 operating at -20 degrees C. The Kweed and van Woerden algorithm was used to determine ToM that occurred on JD 2457184.369757 +/- 0.00007 d. |
2015 May 29 - BL DRA As a warm up to a run of scientific imaging and research, attention was directed towards the binary star system BL Draconids (RA 19h40'24" DECL +60 55' 13"). This star system has a period of 0.4026655 days and has a magnitude range of 11.9 to 12.2mv. Derived from 141 observations, the lightcurve shows the primary eclipse of the system that were extracted from 1 minute exposures through the observatory's 10 inch Schmidt-Cassegrain telescope. All images were taken through a V photometric filter. At the time of imaging, the 85% lit moon was visible throughout the whole session. Transparency stood at +18.22 mag/arcsec^2 and seeing was measured at 3.11" FWHM. Observations revealed that the Time of Minimum (ToM) occurred on JD 2457172.36190 +/- 0.00014 Days. |