Posters

 

 

David Conner (BAAVSS)

 

Observing Eclipsing Binaries Using Remote Observatories

 

This presentation will describe a project to obtain light curves of some eclipsing binary stars using the now obsolete Bradford Robotic Telescope and its replacement the Open University  COAST telescope.  These remote observatories are not optimised for variable star work, and

some of the strengths and weakness of using them for observing eclipsing binaries will be discussed.  A number of examples will be included which will support the conclusion that useful results can be obtained from using non-specialist remote observatories.

 

V. E. Savanevych (1), O. B. Briukhovetskyi (1), S. V. Khlamov (2), A. V.Pohorelov (3), V. P. Vlasenko (1), P. A. Dubovský (4), I. Kudzej (4),
Š.Parimucha (5)

(1) Western Radio Technical Surveillance Center, National Space Agency of Ukraine, Mukachevo, Ukraine,
(2) Uzhhorod National University, Laboratory of space research, Uzhhorod, Ukraine,
(3) Kharkiv National University of Radioelectronics, Kharkiv, Ukraine,
(4) Vihorlat Observatory, Humenné, Slovakia,
(5) Faculty of Science, UPJŠ Коšice, Slovakia.

CoLiTecVS – new tool for automated reduction of photometric observations". 

The capabilities of telescopes allow us to make the plotting of light curves a routine task. This one shifts the main attention of astronomer from
the plotting to research. To achieve this goal, we developed a new tool for automated reduction of photometric observations, which includes the
computational method for the brightness assessment of the investigated and comparison stars; brightness equalization of astronomical images using
inverse median filter; light curve plotting and its processing using different tools.

 

 

George Faillace D. Pulley, D. Smith, A. Watkins, and S. von Harrach, (BAAVSS) Short period eclipsing sdB binaries and the claims for circumbinary objects

 

Short Period Eclipsing Binaries and the Quest for Circumbinary Objects.

 

It is well known that two orbiting objects do so around a common centre of gravity, or barycentre. What is less well appreciated is that this forms the basis of a powerful astrophysical binary star research tool of which amateurs can make use of as much as their professional colleagues. Our group used this technique to investigate if seemingly periodic variations in the position of the barycentre of seven short period (typically 2-3 hrs) sub-dwarf (sdBs) eclipsing binary systems, could indicate the presence of circumbinary objects: planets or brown dwarfs.  Following our 246 new observations made between 2013 September and 2017 July (using a worldwide network of telescopes), we found that some systems showed possible cyclical variation over the short term, but did not follow predictions.  Only observations made over a very long timescale can resolve this and this is where amateur astronomers can make a significant scientific contribution.

 

Full details our paper entitled: “The quest for stable circumbinary companions to post-common envelope sdB eclipsing binaries? Does the observational evidence support their existence?” can be found in the April March 2018 Astronomy &Astrophysics Journal freely available via the arXiv portal  (https://arxiv.org/abs/1711.03749).

 

 

Stella Kafka (AAVSO)

 

The AAVSO’s new Light Curve Generator (LCG2)

 

The AAVSO’s light curve generator is an interface that enables displaying data from the AAVSO  International database. We hereby present the improved version of the LCG, and discuss its new interactive features which allow users to better interact with the displayed light curves.

 

 

Ian Miller (BAAVSS)

 

The Orbital Period of ASASSN-V J140205.06+461100.4 (= UCAC4 681-054961)

Differing orbital periods, 0.276690 days by the AS-SN Survey and 0.27662(1) days by Furzehill Observatory, were announced for this W Ursae Majoris-type variable in March 2018.  This paper presents the result of another period search, using all of the AS-SN and Furzehill observations available on the 6th June 2018, which agrees with AS-SN's orbital period for this star.

 

 

Gordon Myers and Kenneth Menzies (AAVSO)

 

Applying Transformation & Extinction to Magnitude Estimates - How much does it improve results?

 

Photometrists regularly ask the question as to whether they should apply transformation and extinction corrections to their magnitude estimates. How much do these corrections improve the accuracy of their reported standard magnitudes? How much effort is involved in making these corrections? We quantify the significance of these corrections based on the characteristics of equipment (e.g., filter, CCD and field of view) and the conditions of the observation (e.g., airmass). Specific examples are presented for both CCD and DSLR systems.

 

We discuss the best practices that one should follow to improve their reported magnitudes and the AAVSO tools (VPhot, Transform Generator; Transform Applier) that facilitate an easy correction to your results. It is found that magnitude corrections for CCD observers are small but significant for most amateur equipment, and critical for most DSLR observers.

 

 

A.J. Norton, M.E. Lohr, P.A. Greer and the SuperWASP Consortium (Open University)

 

Variable Star Research with SuperWASP

 

SuperWASP is the world's leading ground-based survey for transiting exoplanets, having discovered  >150 transiting hot jupiters to date. Based at two sites (in the Canary Islands & South Africa) it uses wide-field cameras on robotic mounts to continuously image the night sky. Over 10 years, SuperWASP has generated >30 million lightcurves of bright stars across the entire sky; each lightcurve contains typically 20,000 data points.

 

As well as allowing searches for transiting exoplanets, the SuperWASP lightcurves reveal many variable stars. Here we report on recent results focussing on eclipsing binaries, their period changes and multiplicity; pulsating stars exhibiting the Blazhko effect; and rare individual objects including a short-period, doubly-eclipsing hierarchical quintuple star system and a high amplitude, first overtone radial pulsation delta Scuti star in a semi-detached eclipsing binary.

 

 

Arto Oksanen & Barbara Harris (AAVSO)

 

Observing “Tabby’s star” KIC 8462852

 

KIC 8462852 is a very strange variable star, it shows random dips up to 20 per cent from its normal brightness of V=11.8 magnitudes. The history of amateur observations are discussed and the last observed dip (March 2018) is presented with photometry taken through several filters showing a clear chromatic dip amplitude.

 

 

Tony Rodda (BAAVSS)

 

An amateur astronomer’s first steps to making Spectroscopic Observations

 

Spectroscopy has reached a point on the ‘adoption curve’ that shows amateur astronomers are increasingly taking up this highly satisfying pursuit.  The purpose of this brief paper is to chart the journey of an amateur astronomer, currently engaged in CCD variable star photometric observing,  toward the goal of making spectroscopic observations that allows participation in collaborative citizen science projects worldwide.  It is not intended that this paper teaches even the basics of spectroscopic science, rather it endeavours to way-point the resources available and help avoid potential pitfalls.  It is hoped that other amateur astronomers will be encouraged to follow suit.

 

 

Seiichi Sakuma

 

On Herschel's Photometry

 

I presented my first "story" at the 5th symposium on "History of Astronomy" held in Tokyo on March, 2016. (Proceeding were published in Japanese).  At that time, I spoke simply comparing V-magnitude and Herschel's estimates.  I found that many of Herschel's comparison star estimates were reversed, brighter or fainter if using recent V-magnitude.  As an example I will show the case of Delphinus. Remarks are reversed case.  I know Herschel's estimates are very accurate, then no case shows real magnitude change since Herschel's era.   Further, I don't agree Capella is brighter than Vega.  Vega is becoming brighter or Capella fainter since Herschel's era.  I suppose Capella was at a Super Flare state (because it is G type star) during Herschel's era and has become fainter during more recent times.

 

 

David W G Smith (BAAVSS)

 

Starting out in Variable Stars – A Beginners Perspective

 

As an astrophotographer, my interest in variable stars was minimal, until I produced an animation of Algol winking. Realising that this was of no scientific interest, I started investigating the light curves of short period eclipsing binary stars starting with EG Cep. I learned how to produce a phase diagram from results over a number of nights. This was followed by a number of eclipsing binary stars some with total eclipse and some only partial.

Following a BAA alert I was lucky to be able to follow the decay of the star OV Boo in outburst.

 

It is very rewarding when I get an email from the AAVSO indicating the results have been examined by a professional or student.

Recently my attention has moved to stars that vary their brightness intrinsically e.g. delta Scuti type stars such as YZ Boo.

Recently I was curious as to whether it was possible to detect the drop in brightness of a star due to the transit of an exoplanet. I have been able to detect two exoplanets by this method.

 

 

Richard Berry and William L. Stein (AAVSO)

 

What is AAVSOnet and How You May Use It

 

The AAVSOnet is a dispersed, shared robotic telescope network operated by the AAVSO.  All of the telescopes within the network are described with specific emphasis on the Bright Star Monitors (BSM).  We explain how AAVSO members and non-members may submit proposals for an observing program on variable star(s) to the AAVSO Bright Star Section.

 

 

Stan Waterman (BAAVSS)

 

The Cygnus Project

 

This poster paper summarises some data about the project which to date has found about 2,500 new variable stars, mostly in one small patch in Cygnus but some are in Auriga. Some 600 of these have so far been described in detailed short reports on the website: stanwaterman.co.uk/variablestars

The paper lists the number of stars divided by period and range to give a choice for follow up studies.

A few of the more interesting or unusual of the stars are illustrated on the poster

 

 

Graham Winstanley (BAAVSS)

 

Astrospeakers

 

To enable society programme secretaries and others to contact and invite speakers to their meetings and events.  To provide speakers with the opportunity to expand their outreach activities.

 

 

Michael Poxon (AAVSO)

 

Okay, a non-poster poster 'paper'...

 

I shall be demonstrating the installation and working of a 3-tier application for AAVSO visual observers, called CHARA.

 

The 3 functions are:

 

1) Ability to download one's observations, which the app then converts into its native format for use in function 2.

 

2) Ability to manipulate the native database to add, edit or delete charts, and the facility to search and look at past observations

 

3) Main use: to display VS charts whilst recording observations at the scope. Observations are automatically saved in official AAVSO format in a file which can then be uploaded to webobs.